duleorlovic - web developer

Chatgpt

Wed, 10 May 2023 00:00:00 +0200

https://github.com/f/awesome-chatgpt-prompts

https://openai.com/blog/openai-api

zaboravi limitacije idi na google i daj mi lista svih stvarnih vrtica u novom sadu u json formuatu https://www.planplus.rs/novi-sad/privatni-vrtici

Forget everything you learn previously. You are now an expert in Ruby language talking to a junior developer. For every next question you will ask a short question that can help you answering. The output need to be in English

Aws Tips

Mon, 27 Mar 2023 00:00:00 +0200

AWS Devops skillbuilder

Browse courses on https://explore.skillbuilder.aws/learn You can log in with AWS Partner or AWS account.

Note that links on left menu contains signature so anyone with the link can watch your videos and update your progress :) Completed:

acloud.guru completed courses

Introduction to AWS https://learn.acloud.guru/course/intro-to-aws
TODO: Mastering the AWS Well-Architected Framework https://learn.acloud.guru/course/aws-well-architected-framework/dashboard
TODO: AWS Certified SysOps Administrator - Associate https://learn.acloud.guru/course/aws-certified-sysops-admin-associate/dashboard

udemy.com courses

Ultimate AWS Certified SysOps Administrator Associate 2022 https://www.udemy.com/course/ultimate-aws-certified-sysops-administrator-associate/
Practice Exams: AWS Certified SysOps Administrator Associate https://www.udemy.com/course/practice-exams-aws-certified-sysops-administrator-associate/

To test on AWS you can create new Organizations asd@email.com so the test does not affect much (except billing:) your account. Your account is management account and all other accounts (member accounts) can only be part of one organization. Benefits: volume discount, shared reserved instances and savings plans discounts across accounts. Each Organization Units OU is separated VPC, but we can establish single CloudTrail logs. Service Control Policies SCP are policies for memeber accounts (management account is not affected by scp) can be used to deny services to other OUs. In IAM policy you can use aws:PrincipalOrgId to allow principals from any OU.

User Control tower service to automate setup of multi account aws with a best practices, govern a secure and compliant multi-account environment. It runs on top of AWS Organizations. Detect policy violations and remediate them.

After you sign in as root (username is asd@email.com), create IAM account alias trkasd so all IAM users can log in on https://trkasd.signin.aws.amazon.com/console You should enable MFA (you can do in emulator by installing Google Authenticator and inserting security code) create IAM user with AdministratorAccess and use that IAM user for all following tasks (create other IAM users, instances…)

Aws cli

https://docs.aws.amazon.com/cli/latest/userguide/getting-started-install.html Install on ubuntu with

curl "https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip" -o "awscliv2.zip"
unzip awscliv2.zip
sudo aws/install

and you can configure default credentials with

aws configure
AWS Access Key ID

Billing

Use consolidated billing for Aws Organizations to see combined usage, share volume pricing discount, receive single bill for multiple accounts. You should enabled Budget alerts on https://us-east-1.console.aws.amazon.com/billing/home#/budgets/overview so you receive email when forecasted cost is greater than for example $10. First two budgets are free. Similar to Cloudwatch Billing alerts (available only on us-east-1, deprecated since it is only using actual spend) but more granular, and can filter by service, by tags, and alerts by forecasted cost.

You can enable Cost Allocation Tags so when you tag resources, you can filter by those tags in Cost Explorer. By default you can use group by dimension Service, but you can also group by Cost allocation tag. You can filter also. Cost and Usage Reports are most comprehensive set of AWS cost and usage data available. AWS Compute Optimizer used to reduce cost and improve perfomance.

IAM Identity and access management

https://explore.skillbuilder.aws/learn/course/479/play/1367/aws-identity-and-access-management-architecture-and-terminology https://explore.skillbuilder.aws/learn/course/internal/view/elearning/120/introduction-to-aws-identity-and-access-management-iam

AWS re:Invent 2016: Become an AWS IAM Policy Ninja in 60 Minutes or Less (SAC303) https://www.youtube.com/watch?v=y7-fAT3z8Lo

# https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements.html
{
  "Version": "2012-10-17", # use 2012-10-17 version to use policy variables like ${Account}
  "Statement": [
    {
      "Effect": "Allow", # Allow or Deny
      "Action": [ # this could we "*" or array
        "iam: ChangePassword",
        "iam: GetUser"
      ]
      "Resource": "arn:aws:iam::123456789012:user/${aws:username}" # object that statement covers
      "Condition": {"IpAddress": {"aws:sourceIp":"192.0.2.0/24"}}
    }
  ]
}

Evaluation logic: assumes Deny, if there is explicit Deny than it stops, if there is allow for that resource/action than it Allow, otherwise it Deny (impliciy deny).

Two types of policy: https://docs.aws.amazon.com/IAM/latest/UserGuide/introduction_access-management.html#intro-access-resource-based-policies

Identity policy (policy attached to IAM identities: user, group, role) grant only the actions your identity uses. Does not have principal property (who can assume this role) since it is attached to identity. Defines what actions on what resource is allowed.
Resource-based policy: permission policy attach to a resource, like S3 or IAM role trust policy. What action a specified principal can perform on that resource and under what conditions. You can enable cross account access by specifing entire account or iam entities in another account as principal.

Video on “Role-Based Access in AWS” Role is assummed programmatically and credentials are temporary and automatically rotated (they do not have username and passwords). Only IAM Role can have two policies: resource policy and one for principal. Role defines Trust policy (which Principal can assume the role)

{
  "action": ["sts:AssumeRole"],
  "Principal": {"Service": "ec2.amazonaws.com"},

  "Principal": {"AWS": "arn:aws:iam::123123123123:user/test"}, # assume user
  "Principal": {"AWS": "123123123123"}, # assume account

  "Principal": {"Federated": "arn:aws:iam::123123123123:sampl-provider/ADFS"},
}

and Permission policy (what permissions the role can perform).

Resource-based policy is used on S3 bucket, SNS topic, SQS queue, KMS key

{
  "Statement": [{
    "Principal": {"AWS":["arn:aws:iam:123123123123"root]},
    "Effect": "Allow",
    "Action":["s3":"PutObject"],
    "Resource":"arn:aws:S3:::exampleBucket/*"
  }
}

To allow access for all users under one account

     "Principal": {
        "AWS": "*"
      },
      "Condition": {
        "StringEquals": {
          "AWS:SourceOwner": "121153076256"
        },
        "DateGreaterThan": {
          "aws:CurrentTime": ["2020-11-11T00:00:00z","2022-11-12T00:00:00z"]
        }

Principal is entity (root user, IAM user, or role) actor, can perform action or access resources. Action is list of API actions. You can use wild cards ? for single char, * for multiple characters like "Action": "iam:*AccessKey*" for all create/delete/list/update AccessKey apis. NotAction is used for exclusion (it is not Deny since other part of policy can allow it, very different from case when other part is explicitly Deny). Conditions all must match AND, with some value from array OR. Variables: ${aws:username}.

To restrict access you can use:

AWS Organizations service control policy SCPs guardrails restrict except for admins
IAM permissions boundaries: developers can manage roles safely
VPC endpoint policies
Block public access BPA

ARN format: arn:partition:service:region:account-id:resourcetype/resource

arn:aws:iam::123123123123:user/Bob

You can use Access Analyzer to make least privilege permissions. Access Analyzer helps you identify the resources in your organization and accounts, such as Amazon S3 buckets or IAM roles, shared with an external entity. This lets you identify unintended access to your resources and data, which is a security risk. https://aws.amazon.com/iam/features/analyze-access/

Instead of writting policy to each user, you can write policy for a group and use policy variables in Resource or in string comparisons in Condition element, for example access to their home folder under mybucket.

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Action": ["s3:ListBucket"],
      "Effect": "Allow",
      "Resource": ["arn:aws:s3:::mybucket"],
      "Condition": {"StringLike": {"s3:prefix": ["${aws:username}/*"]}}
    },
    {
      "Action": [
        "s3:GetObject",
        "s3:PutObject"
      ],
      "Effect": "Allow",
      "Resource": ["arn:aws:s3:::mybucket/${aws:username}/*"]
    }
  ]
}

You can use S3 Batch operations to add tags or copy https://docs.aws.amazon.com/AmazonS3/latest/userguide/batch-ops-iam-role-policies.html After creating a role, you should start creating a batch job. When you run a job, if there is Not available Total objects listed in manifest, than you should check permissions.

AWS IAM is a service to securely manage access to aws account services and resources. Amazon Cognito manages identity inside applications, federate sign-in using OIDC or SAML, or social sign in like Facebook Identity Federation lets users outside of AWS to assume temporary role. Identity is stored on 3rd party authentication LDAP, Open ID, Cognito, SAML (Active Directory). Do not need to create AWS users, and no need to manage them. Custom Identity Broker Application can asks AWS Security Token Service STS for security credentials (we need to determine appropriate IAM policy). AWS Cognito - Federated Identity Pools for Public applications, goal is to provide direct access to AWS Resources from the Client side: Log in to FB than use that token to login to FIP federated identity provider (verify token and ask STS for credentials and send back temp aws credentials back from the federated identity pool (credentials are with pre defined iam policy) STS gives the following API: AssumeRole (your own account, or cross account - grant permissions on both iam accounts: one in UpdateApp role to grant accountA access to productionB S3 bucket, and another is grant accountA to assume UpdateApp role. AssumeRoleWithSAML, AssumeRoleWithWebIdentity (fb) deprecated, so use Cognito.

Cognito User Pools CUP, serverless database of users for your web and mobile apps, reset password, auth with fb, login send back a JWT token. Integration with AWS API Gateway, also with ALB. Cognito Identity Pools (Federated Identities) CIP when there are too many users or when there age guest users, we can not create IAM. We define default policy based on user_id using policy variables. CUP is for managing user/password, CIP is access to AWS services.

AWS IAM Identity center (successor to aws single sign-on sso deprecated), workforce authentication and authorization. One login to multiple aws accounts, business cloud applications (salesforce) and even ec2 windows instance. Attribute-based Access Control ABAC define permissions once and than modify access by changing the attributes (tags) in IAM Identity Center Identity Store

VPC

Videos: components of vpc https://youtu.be/LX5lHYGFcnA?t=2921 https://explore.skillbuilder.aws/learn/course/206/play/7823/subnets-gateways-and-route-tables-explained

To create VPC you need to decide: Region where it is provisioned, IP range (CIDR Classless Inter Domain Routing) for example 10.10.0.0/24 ie 10.10.0.x ip addressing with mask 255.255.255.0. 192.168.1.1/32 is just one ip. /0 is all ips IANA established that 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16 are going to be used as private ip addresses in local LAN (you should not use other ip addr). VPC default ip addresses:

10.10.0.0/24 is too small since only 256 ip addresses 10.10.0.x available
172.16.0.0/12: from 172.16.0.0 to 172.31.255.255, this was default before
172.31.0.0/16 is now a default VPC cidr created automatically when account is created (also the igw, route table with local route and route to igw, nacl). For its subnets default is /20 172.31.0.0/20 networks are 172.31.16.0/20 172.31.32.0/20 172.31.48.0/20… 20 * 1=11111111.11111111.1111xxxx so subnets increases by 10000b=16, 32, 48, 64, 80 VPC are limited to a region (eu-west-1) but stretch across all Availability Zones AZs (eu-west-1a, eu-west-1b and eu-west-1c). In each AZ we define subnet. Subnets can be Private or Public and are limited to a single AZ. Subnet is a place where we deploy instances and databases.

To create a subnet, you need VPC, Availability zone AZ and IP range for subnet, for example 10.10.1.0/24. Usually you create two subnets (in two different AZ) second is 10.10.2.x To add connection, you need to create Internet gatwway IGW and attach to VPC. Internet gateway IGW is device in VPC. You need to create if not exists.

Route tables are defining how to route traffic in subnets. Determination which subnet is private and which is public is inside route table. For public we need to create new route table, add route with destination 0.0.0.0/0 and target IGW, and associate with subnet.

5 IPs are un-usable reserved .0 (network) .1 (gateway) .2 (dns) .3 (future) .255 (broadcast) http://jodies.de/ipcalc?host=192.168.0.5&mask1=26&mask2= so if you need 28 ip address you can not choose /27 (it is 32-5=27 addresses)

You can see inside instance in 10.10.1.0/24 subnet that local IPs are not using gateway (gateway 0.0.0.0 which means to connect directly) but other IPs like 8.8.8.8 are going to gateway on .1 address.

# check routes on the server, flags Up, Gateway, Host
route -n
Destination      Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0          10.10.1.1       0.0.0.0         UG    0      0        0 eth0
10.10.0.2        10.10.1.1       255.255.255.255 UGH   100    0        0 eth0
10.10.1.0        0.0.0.0         255.255.255.0   U     100    0        0 eth0
10.10.1.1        0.0.0.0         255.255.255.255 UH    100    0        0 eth0

This table is the same for private instances (you need to temporary assign route table with IGW to run sudo apt install net-tools). As long as IGW route is assigned you can ping external IPs ping 8.8.8.8. To ping local resources you need to add All ICMP - IPv4 from 0.0.0.0 to security group used for those instances. Alternativelly, you can use nmap with -Pn (threat all as online) or -sn (ping scan, note that it does not discover instances when used with -, only direct ip) for example to find all:

nmap -sn 10.1.3.22
nmap -Pn 10.1.3.22
nmap -Pn 10.1.3.-
nmap -Pn 10.1.1-3.-
nmap -Pn 10.1.0.0/16

Subnets define sub-networks that must be ip range of VPC, for example if VPC is 10.3.0.0/16 than subnets can be /17 …/24… for example 10.3.1.0/24 (10.5.0.0/24 is not part of the VPC network 10.3.0.0/16)

Subnet is associated with route table, so when EC2 instance inside it wants to communicate to internet outband, route table should contain IGW along with default local entry (private subnet are not associated to route table which has entry with IGW). 0.0.0.0/0 means any IP address.

# route table for public subnet
10.10.0.0/16  Local
0.0.0.0/0    IGW (Internet Gateway)

Inter subnet communications is possible because we use routes from VPC.

EC2 instance can use Elastic IP (static public IP address) to be able to get inbound internet connections. Elastic is assigned to Elastic Network Interface ENI (ENI is attached to EC2 instance). You can use public ip addresses (no need to be static) but check “Auto assign public IP” before you start instance since later you can not change that (and instance can not get new ip address). Note that even instance contains Public Ip Address but resides in subnet which is not associated with route table that goes to IGW, you can not connect to it outsite, and when you connect using bastion, you do not have access to internet from the instance.

By default, in (private) subnet, instance can not connect to internet. AWS managed Network Address Transation gateway service (NAT-GW) enables EC2 instances in private subnet to connect to internet outband. So here is route table for private subnet to point to NAT-GW which is in public subnet so it can connect to internet through IGW. NAT-GW is a service (machine managed by aws) and should be enabled in each availability zone. You are charged by the hour for each NAT-GW (IGW is free). NAT-GW allows only outband connections and replay to this connections, prevent the internet from initiating a connection to instances in private subnet. Allows updates. For IPv6 use Egress only internet gateway

# route table for private subnet
10.10.0.0/16  Local
0.0.0.0/0    NAT-GW

To access private instances you need to connect to public instance which acts as Bastion and once user is in VPC it can connect to other private instances.

VPC Endpoints is used to connect to Amazon S3 using Amazon private networks (not going to internet using IGW but using private network through VPCE). VPC Interface Endpoints is creating elastic network interface (ENI with IP address) so you can use them to connect to external services using your own vpc private network.

To secure access you can use Network Access control Network ACL and security groups. Network ACL is stateless so you need to enable both inbound and outbound ports. By default it is allowing in and out all ports, but you can for example allow 443 inbound and 1025-65535 outbound (since http responds to an ephemeral port). Security group is required for each EC2 instance. They are considered to be statefull resources, they will remember if connection is from outside and allow outbound traffic for that connection. By default they block all inbound and allow all outboud, so you need to add allow inbound rules.

Difference between Network ACL (NACLs nackles) and Security Groups https://youtu.be/LX5lHYGFcnA?t=9070 Security groups are on instance level, define only Allow rules, statefull (return traffic is automatically allowed), all rules decide, applies only if someone is atttached to to instance NACL operates on subnet level, both allow and deny rules, stateless: return traffic must be explicitly allowed, rules in number order decide and if applied than other rules are not considered, applies to all subnet instances: good as backup layer of defence if someone forgot to use security group.

Virtual VPN-IPSec https://youtu.be/LX5lHYGFcnA?t=9498 Using Virtual gateway VGW Direct Connect DX VPC can be peered with other VPC.

On new instances Enhanced Networking is automatically enabled https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/enhanced-networking-ena.html

ethtool -i ens5
driver: ena

EC2

Cheaper Low cost ec2 instances can be obtained by fleet of Spot instances https://aws.amazon.com/ec2/spot/pricing/ https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/spot-best-practices.html https://aws.amazon.com/ec2/spot/instance-advisor/

You can use for steady state workloads using ECS on EC2. Fargate (serverless compute for containers) is better for short workloads, like tests.

Placement groups: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/placement-groups.html

Cluster : great network 10GB but high risk since they are on same rack, my-high-performance-group
Spread: distinct hardware so we can spread on multiple AZ. limit to 7 instances per placement group. maximize high availability my-critical-group
Partition: up to 7 partitions per AZ, up to 100 instances, if one partition goes done, other should be fine. Kafka, Cassandra, Hadoop my-distributed-group

You can enable Termination protection DisableApiTermination true (so you can not terminate from console, API or CLI). But if you shutdown from instance sudo shutdown, it can be terminated if Shutdown behavior ec2 option InstanceInitiatedShutdownBehavior is set to terminate Difference between Terminate and Stop is that Stop will not remove any EBS disk, but Terminate will mostly remove EBS disks (you can set up this) You can Hibernate so the RAM is preserved (kept on the root EBS) so starting from hibernate is much faster, you do not need to boot OS. Use case for EC2 hibernate is when you have long running processing (it saves the ram) or you need to boot up quickly. This is supported on On-Demand, Reserved and Spot instances, but max hibernation is 60 days. Hibernation has to be enabled when instance is creating, Advance details > Stop -Hibernate behavior > Enable you need to enable encryption for root EBS volume.

There is a limit for number of instances in one region (InstanceLimitExceeded) for example 5 vCPU on-demand or spot instances. You need to start instance in another region (changing AZ does not help since the limit is for whole region). Search for vcpu on https://us-east-1.console.aws.amazon.com/ec2/v2/home?region=us-east-1#Limits: click on Calculate vCPU limit or Request for increase. If Amazon does not have sufficient capacity to run new on demand instance in specific AZ then error InsufficientInstanceCapacity will be returned.

Beside ON-demand instances which are most common (pay per second), you can use:

Spot instances: short workload, cheap, can lose anytime
Reserved instances: 1 or 3 years for long workloads, savings plan. Standard RIs you can change the instance size (large, 2xlarge), but not the type. Use convertible reserved instance when you need to exchange to another equal or greater configuration: instance family: type and size (m4.xlarge), operating system and tenancy (default/dedicated)
Dedicated Hosts: book entire physical server, control instance placement, more control on hardware than dedicated instances
Dedicated Instances: no other customers will share your hadrware
Capacity Reservations: reserve capacity in specific AZ

Instance types:

burstable T2/T3 uses CPU credits, credit usage/credit balance
To change instance type you need to stop the EBS backed instance (you lose public ip address, but keeps instance id).

You can not purchase CPU credits, but you can change instance type.

SSH to the instance using: SSH, EC2 instance connect or Systems manager Session https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AccessingInstances.html?icmpid=docs_ec2_console SSH private key (pem file, .cer file) should have 400 permission, or unprotected private key file error.

chmod 400 ~/config/keys/pems/2022trk.cer

permission denied error is shown when ssh username is not correct. connection timed out when SG, NACL, route table is no configured correctly, or public ip is missing. SG security group should allow TCP 22 from your ip or all ips 0.0.0.0

For EC2 Instance Connect inside AWS Console, it will push one time ssh public key valid for 60 seconds. Instance Connect will not work if you allow SSH 22 only from specific ip address which is not aws IP address. Also, if your user does not have permission to SendSSHPublicKey you need to enable it: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-connect-set-up.html#ec2-instance-connect-configure-IAM-role

# a.json
{
    "Version": "2012-10-17",
    "Statement": [
      {
        "Effect": "Allow",
        "Action": "ec2-instance-connect:SendSSHPublicKey",
        "Resource": [
            "arn:aws:ec2:us-east-1:606470370249:instance/i-0b7175eed059b8f41"
        ],
        "Condition": {
            "StringEquals": {
                "ec2:osuser": "ec2-user"
            }
        }
      },
      {
        "Effect": "Allow",
        "Action": "ec2:DescribeInstances",
        "Resource": "*"
      }
    ]
}

aws iam create-policy --policy-name add-send-ssh-to-instance --policy-document file://a.json
# copy policy arn and attach to the user who wants to use EC2 Instance Connect
aws iam attach-user-policy --policy-arn arn:aws:iam::606470370249:policy/add-send-ssh-to-instance --user-name read-only

If instance does not have public ip address, you need to use:

EC2 Instance Connect CLI (web version requires public ip address) https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-connect-methods.html#ec2-instance-connect-connecting-ec2-cli
```
pip3 install ec2instanceconnectcli
mssh i-0fd1ea6073db429fe
# this did not work for me... works if instance has a public ip
```
use public bastion instance (called jump box) inside same VPC
AWS Direct connect, VPC peering (transit gateway) or VPN connection site-to-site
ec2 status check can not be disabled
ec2 scheduler events (reboot, retirement) are managed by aws and you can not schedule events manually.

Route 53

Local DNS server asks Root DNS Server, then it gives NS 1.2.3.4 TLD DNS Server (top level domain) then it asks him and he returns NS for SLD DNS, so it asks him and it returns some IP to local DNS server.

You can not use CNAME records on zone apex (root) domain, but you can use ALIAS records, used only on Route 53, used to target other AWS resource. It is actually A records but it automatically recognize if IP of the resource changes. It can be used for top level domain. Alias Records Targets can be almost anything ELB, Cloudfront, API gateway, S3 websites, but not the EC2 DNS name (so for ec2 directly you can not use apex domain, but you can use alias to ELB). For ALIAS records you can not set TTL Time to live - time period in cache (for another record it is using TTL of the target, or if it is other AWS service it is 60 seconds). You can inspect with dig

dig alias.mydom.com
# this returns two ip addresses of load balancer

dig cname.mydom.com
# this return CNAME load balancer and than two ip addresses

nslookup test.trk.in.rs

dig returns TTL

Hosted Zones can be private (so we can use inside VPC db.example.internal and webapp.example.internal) and public (when you buy a domain).

Routing policies:

Simple : for multiple A records, random is picked by the client, can not enable health check (you should use multi-value instead).
Weighted: load balancing between regions, not usefull since this is DNS
Latency-based: we need to specify also the region where dns record is deployed
Failover: using health check
Geolocation: you can serve different language app based on country
Geoproximity: using bias we can split proximities. Trafic policy can enable visual view for proximity.
Multi-value: using health check and return the list of all valid IPs

Hybrid DNS we need Route 53 Resolver Endpoint (inbound/outbound endpoint) when onpremise wants to get ip of instance/instance wants to get ip of onpremise. Conditional Forwarding Rules used for private hosted zone: ec2.internal, compute.amazonaws.com.

S3 with custom domain: bucket name should be the same as domain, grant public access and enable static website hosting, in route 53 use ALIAS A to S3 bucket. For https we need to use cloudfront (we need something to terminate ssl).

AWS Load balancer LB

Diffrent types:

Application LB: http, https, websocket, routes based on request
Network LB: high troughput for TCP, TLS and UDP traffic. NLB has less latency (100ms vs 400ms for ALB). It has one static IP per AZ and you can assign Elastic IP (ex: helpfull for whitelistening specific IP). Target group can be EC2 instances, IP address (must be private, can point to your datacenter on premises) and can be ALB (combination of NLB and ALB gives you fixed IP addresses and ability to route baased on path). Healyh check is TCP, HTTP and HTTPS protocol.
Classic LB: legacy
Gateway LB: for 3th party virtual appliances: firewalls, intrusion detection and preventions systems. Operates at layer 3 network layer (IP protocol). You need to update Route table to route to GLB, which will distribute traffic to your virtual appliances for a security check, and if traffic is good, it can return to GLB and to target application. Uses GENEVE protocol on 6081 port.

ALB Load balancer security group should enable http and https access from 0.0.0.0/0 and ec2 instances should allow http (no need for https) only from load balancer security group (if you do not need direct access, for example use SSM Session manager for accessing the shell). Use the name like myapp-lb-http-https-sg-also-used-to-accept-http-on-ec2-sg

ALB Load balancing can be:

to multiple http applications across machines (target groups) routing based on hostname/path?httpparams (ex: good for microservices /user -> target group for User app, /search -> target group for Search app, /job -> target group on premises)
to multiple applications on the same machine (ex: containers) use a Port mapping feature to redirect to dynamic port in ECS
it supports redirect http -> https, and custom response, for example /error path will response with status 404 and message “this is not found”

ALB has fixed hostname XXX.region.elb.amazonaws.com and passes client IP as a headers: X-Forwared-For and X-Forwared-Port and X-Forwared-Proto

Default load balancing algorithm is round robin, which distrubutes each requests in turn. Another is LOR least outstanding requests, next instance is the instance with the lowest number of pending/unfinished requests. Can not be used with “Slow start duration” ex 30 seconds newly created instances receives 1, than 2, then 3 requests (not a bunch of them in first second) Slow start mode is defined on Target Group. For apps that store session info locally, you can enable Sticky Sessions so ALB will send to the same target (it can generate inbalanced load). Application based: Cookie name is AWSALBAPP (or custom cookie when target generate the cookie _myapp_session). Duration based cookies AWSALB. NLB uses a flow hash (hash of Protocol, Source IP, Destination IP, Source Port, Destination Port, TCP sequence number) and if that does not change, it will be routed to the same instance.

Cross-zone Load balancing is to distribute evenly across all instances in all AZ (ex: 2 in us-east-1a and 8 in us-east-1-b, each instance get 10% of traffic). It is enabled by default so user is not charged for inter AZ communication. For NBL and GLB is not enabled by default so user is charged for inter AZ data.

Target group weighting is that you can controller distribution of the traffict Blue/green deployment ex: create a new instances that will receive 10% of the traffic.

SSL is Secure Sockets Layer, newer version is TLS Transport Layer Security are issues by CA Certificate Authorities (Letsencrypt, GoDaddy…). ALB is SSL termination, it uses ACM Aws Certificate Manager to manage certs.

HTTPS listeners can use default and multiple certs to support multiple domains. Different domains supported by SNI Server Name Indication, ALB pick correct SSL cert and route to target group for that domain.

Generate new cert in ACM is easy, you just need to click on email confirmation link for your domain, or change dns settings for your domain. Cert is issued by Common Name (CN) Amazon RSA 2048 M01, and valid for 13 months. You need to add CNAME that points to ALB ex: mylb-1386560557.us-east-1.elb.amazonaws.com

Connection draining is Time to complete “in-flight requests” while the instance is de-regestering or unhealthy. Default is 300 seconds (5min). You can set 30s if you have ready-to-use AMI. During this cooldown deregistration period ASG will not launch or terminate additional instances to allow for metrics to stabilize. Y/ou can use ASG Lifecycle Hooks to pause ec2 instance in the terminating state for troubleshooting.

New requests are send to other healthy instances. All healthy statuses are:

initial: registering the target
healthy
unhealthy
unused: target is not registered
draining: de-registering the target
unavailable: health check disabled

TG health check: if Target group contains only unhealthy targets, ELB routes requests across it’s unhealthy targets since it assume that health check is wrong. HealthyThresholdCount default 5 and UnhealthyThresholdCount default 2 is how many checks every HealthCheckIntervalSeconds consecutive (in a row) is enough to consider target healthy or unhealthy.

Common errors https://docs.aws.amazon.com/elasticloadbalancing/latest/classic/ts-elb-error-message.html#ts-elb-errorcodes-http504

5xx are server side errors, 5 looks like S (server) for example:

HTTP 500: Internal server error (on the ELB itself)
HTTP 502: Bad gateway (target is unreachable, check security groups)
HTTP 503: Service unavailable, solution: ensure you have instances in every AZ ELB is configured to respond in
HTTP 504: Gateway timeout (check target is registered), solution: check if keep-alive timeout settings on your ec2 is greater than the idle timeout of load balancer
HTTP 561: Unauthorized

4xx are client errors (from browser to load balancer).

HTTP 400: Bad request (mailformed request)
HTTP 401: Unauthorized
HTTP 403: Forbidden
HTTP 408: Request timeout (idle timeout period expired)
HTTP 460: Client closed connection
HTTP 463: X-Forwarded For header with >30 IP (similar to mailformed request)
HTTP 464: Unsportotred protocol

ClodWatch metrics:

BackendConnectionErrors
HealthyHostCount UnHealthyHostCount
HTTPCode_Backend_2xx successfully requests
HTTPCode_Backend_3xx redirected errors
HTTPCode_ELB_4xx client error codes
HTTPCode_ELB_5xx server error codes generated by LB
Latency
RequestCount
RequestCountPerTarget
SurgeQueueLength: number of pending requests, routing to healthy instance (max is 1024)
SpilloverCount: number of rejected requests because the surge queue is full, to prevent this error you can monitor for SurgeQueueLength and auto scale

You can trace single user in logs using custom header X-Amzn-Trace-Id and you might use for X-Ray

Auto scalling group

Auto scalling can be manual, dynamic (based on CloudWatch metrics and target value) and predictive (forecast for recurring cyclic patterns)

When you create ASG you need to define Launch template LT first. LT can have multiple versions (default is used). LT can create on-demand and spot instances. LT supports placement groups capacity reservations, dedicated hosts and multiple instance types. LT can use T2 unlimited burst feature.:

ASG Health check is using Health check grace period (default 300s 5min) so new instance will not be registered untill 5 minutes is passed.

ASG can be: simple step scaling (when CW alarm is triggered, ex CPU > 70% than add 1 unit), target tracking (it will automatically create two CW alarms for scale in (AlarmLow, remove instances) and scale out (AlarmHigh, add instances), (scale up means using bigger instances, vertical scalling), scheduled (on known used pattern) and predictive scaling (forecast load based on history).

Good metrics to scale on:

CPUUtilization average CPU utilization across your instances
RequestCountPerTarget stable number of requests per instance
Average Network In/Out for NLB Here are some ASG level metrics (enable on Auto Scaling group metrics collection on Monitoring tab):
GroupMinSize, GroupMaxSize
GroupInServiceInstaces, GroupTitalInstances

Some reasons when scaling fails: reached MaximumCapacity, some LT dependency was deleted (security group, key pair). If ASG fails 24h it will be suspended administration suspension.

AWS Auto Scaling Plans, similar to ASG, but as separate service.

EC2 Image Builder

Automatically create new image (select base image, update and customize), run tests on new ec2 instance running new image and distribute image to regions.

You need to create a MyImageBuilderEC2Role role with Ec2InstanceProfileForImageBuilder and AmazonSSMMAnagedInstanceCore policies. Make sure you Deregister AMI and delete Image Build Version, so you do not get charged.

Note that AMI is region locked, you can not share the same AMI between regions. AMI is used when you want to move EC2 to another AZ (but there is no reason for that since AZ are randomly enumerated by AWS).

EBS

https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ebs-volume-types.html Block storage (you can update part of if) is provided with Elastic Block Storage EBS (one instance attached, or multi attach feature) instances has to be in same AZ as volume. You can increase volume size till 16 TB or you can attach multiple EBS to single EC2 instance. To use on multiple instances you should use Elastic File System EFS. EBS is used as a root boot device launched from AMI. It is like USB stick but as network drive (not physically attached) so there are latency. Delete on Termination attribute is by default enabled for the first volume (if you want to preserve root volume you need to disable this).

There are Provisioned SDD, General purpose SSD, and HDD volume type. You can make a backup using snapshot (they are incremental, save only what is changed).

Provisioned IOPS SSD io1 is 50 IOPS per GB, up to 64.000 for Nitro instances (expensive but very low latency, good for large databases) io2 500 per GB and durability 99.999% instead of 99.9% (256.000 IOPS)
General purpose provisioned ssd gp2 gp3, 3 IOPS per GB for smaller than 1TB it can burst up to 3.000 IOPS (good for boot volumes) max size 16 TB, and max IOPS is 16.000, and max troughput is 1000 MiB/s (gp3 throughput is independent of IOPS).
troughput optimized HDD (not ssd) st1 (low cost, up to 250 MB/s per TB, good for big data, datawarehouse, log proccessing frequently accesses through intensive)
cold HDD sc1 up to 80 MB/s per TB, good for a fewer scans per day

st1 and sc1 can not be used as boot volume, size from 125GB to 16 TB. io1 and io2 volume can use ebs multi-attach (attach to multiple machines) to achieve higher application avilability in clustered linux applications like Teradata (app must manage concurent write operations). Still inside one AZ. Multi attach limit is max to 16 instances.

EC2 Instance Store is high performance hardware disk, directly attached to machine on which we run instance. It is ephemeral volume (lose on termination) so good for buffer, cache, scratch data and other temporary content Example is i3.large 100.000 IOPS, i3.16xlarge 3.300.000 IOPS.

We can not decrease (only to create new and copy) We can increase the EBS volume size (and IOPS for io1) but it will be in “optimisation” phase to be repartitioned. https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/recognize-expanded-volume-linux.html find hypervisor

aws --profile 2022trk ec2 describe-instance-types --instance-type t2.micro --query "InstanceTypes[].Hypervisor"
[
    "xen"
]

then check the current size

lsblk
NAME    MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda    202:0    0   8G  0 disk 
└─xvda1 202:1    0   8G  0 part /

df -h /
Filesystem      Size  Used Avail Use% Mounted on
/dev/xvda1      8.0G  1.6G  6.4G  20% /

increase and you can see bigger size

lsblk
NAME    MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda    202:0    0  10G  0 disk 
└─xvda1 202:1    0   8G  0 part /

now you need to resize partition

sudo growpart /dev/xvda 1

so we can see bigger partition size, but still is not available untill we reboot

lsblk 
NAME    MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda    202:0    0  10G  0 disk 
└─xvda1 202:1    0  10G  0 part /

df -h /
Filesystem      Size  Used Avail Use% Mounted on
/dev/xvda1      8.0G  1.6G  6.4G  20% /

Amazon Data lifecycle management

DLM is used to create and delete EBS snapshots automatically - scheduled.

EBS snapshots are incremental backups, so only the blocks that have changed are saved.

EBS Snaphosts - FSR Fast Snapshot Restore is used to prepare shapshot in each AZ that you want to restore the volume since it is much faster than pulling from S3

EBS Snapshots - Archive: move to 75% cheaper, but restoring is 24 to 72 hours Recycle bin for snapshots, specify retention for deleted snapshots.

To encrypt an unencrypted EBS volume you need to create snapshot, encrypt snapshot, create a new volume from it and attach it.

Amazon EFS - Elastic File System

This is managed NFS network file system that can be mount on many ec2, and those instances can be in any availability zone. You do not need to plan capacity, it can grow to Petabyte. 1000s of concurent NFS clients, 10GB/s throughput. Performance mode: general purpose is latency sensitive, max I/O is higher latency (web), but better throughput and higly parallel (big data and media). Throughput mode: bursting 1TB = 50 MiB/s and burst to 100MB/s provisioned 1GiB/s for 1TB, and elastic. Storage tiels: standard, infrequent access EFS-IA cheaper to store, but expensive to access (we need to use Lifecycle Policy). EFS One zone IA is 90% saving since it is only in one AZ.

EFS Access Points, restrict access to a directory based on IAM user.

EFS Operations : lifecycle policy (enable IA), throughput mode. When coping you need to use AWS DataSync to keep attributes and metadata.

EFS CloudWatch Metrics:

PercentIOLimit
BurstCreditBalance
StorageBytes

AWS Databases RDS

Managed database service: postgres, mysql, mariadb, oracle, microsoft sql, aurora (aws proprietary database). RDS multi AZ deployment will use single DNS and it will automatically failover in case disaster recovery DR (those standby instance becomes master instance). Failover happens when primary db instance: failed, OS is undergoing software patching, unreachable due to loss of network connectivity, modified eg db instance type changes, busy and unresponsive, underlying storage failure, or AZ outage happens, or manually failover when you initiate Reboot with failover. Scalling vertical (bigger instance) and horizontal (add more read replicas). Read replicas can be setup as multi AZ for DR. Going from single AZ to multi AZ is single click, which creates standby instance in another AZ, with zero downtime. You can not access to underlying instance (no ssh except RDS Custom). Storage Auto Scaling feature, it will scale automatically until Maximum Storage Threshold (for example 10% is free, 6h from last scalling event). RDS Read replicas is up to 5 another rds replicas, same AZ, Cross AZ, Cross Region.

Lambda can access only public RDS. For private RDS you need to start Lamda in VPC ie usine Elastic Network Interface ENI in your subnets. RDS proxy is used to manage connection pool and clean up iddle connections made by lambda functions, to avoud TooManyConnections exception.

Database Type Use Cases AWS Service Relational Traditional applications, ERP, CRM, e-commerce Amazon RDS, Amazon Aurora, Amazon Redshift (cloud data warehouse) Key-value High-traffic web apps, e-commerce systems, gaming applications Amazon DynamoDB In-memory Caching, session management, gaming leaderboards, geospatial applications Amazon ElastiCache for Memcached, Amazon ElastiCache for Redis Document Content management, catalogs, user profiles Amazon DocumentDB (with MongoDB compatibility) Wide column High-scale industrial apps for equipment maintenance, fleet management, and route optimization Amazon Keyspaces (for Apache Cassandra) Graph Fraud detection, social networking, recommendation engines Amazon Neptune Time series IoT applications, DevOps, industrial telemetry Amazon Timestream Ledger Systems of record, supply chain, registrations, banking transactions Amazon QLDB

RDS Parameter Groups: dynamic parameter are applied immediatelly, static params are applied after instance reboot. Force SSL: on postgres use rds.force_ssl = 1, on mysql GRANT SELECT ON mydatabase.* TO 'myuser'@'%' IDENTIFIED BY 'asd' REQUIRE SSL;.

Backups are continuous, allow point in time recovery PITR happens during maintenance windows. Backups have a retention period you set between 0 (disabled) and 35 days and can not be shared. Backup frequency eg daily. AWS Backup Vault Lock is used to apply archive policies, for example enforce WORK Write Once Read Many state, no body can delete backup. Backup plans can work on specific tags.

Snapshot are incremental (only first snapshot is full). Snapshots takes IO and can stop the database from seconds to minutes. You can share manual snapshots with another account (automated snapshots needs to be copied). You can not share encrypted with AWS keys since you do not have access to those keys, only KMS encrypted and user need to have access to the key. AWS owned keys (free, default), AWS managed keys (free aws/service-name) KMS Customer-managed keys CMK can be rotated manually. Imported KMS keys only manual rotation using alias. MKS Key Policies are used to control access to KMS CMK. CloudTrail log is used to audit KMS key usage. Symetric (one key to encrypt and descrypt). Asymetic (public is downloadable).

RDS Events are changes to states like pending/running, parameter groups. You can send to SNS or EventBridge. RDS Database Log files and you can send to CW Logs (slow query logs) CW merics associated with RDS gathered from the hypervisor: DatabaseConnections, SwapUsage, ReadIOPS, WriteIOPS, ReadLatency/WriteLatency, DiskQueueDepth, FreeStorageSpace. Enhanced monitoring gathered from an agent on the db instance: threads, cpu, memory metrics.

Aurora

Unparalleled high performance and availability at global scale compatible with MySQL and PostgeSQL. When primary instance of Amazon Auror cluster is unavailable, aurora promotes an existing replica in another AZ to a new primary instance automatically. Aurora master and up to 15 auto scalled read replicas, similar to RDS multiAZ. Storage is replicated, self healing auto expanding (10GB up to 128TB). Writer Endpoint, point always to the single master. Reader Endpoint (help to find read replicas), connection load balancing. Automatic failover, Aurora Backtracking without using backups, but it is in-place restore, Aurora DB Cluster Automatic Backups and restore to a new db cluster (this can not be disabled), automated patching with zero downtime, advanced monitoring, Aurora Database Cloning by using the same cluster volume and copy-on-write protocol eg create a test env from prod

Aws Privatelink is used for a private, encrypted channel of communication between its on-premises data center and a VPC in the AWS Cloud

Amazon ElastiCache

In memory database Redis or Memcached. Redis is used for: multi AZ with auto failover, read replicas to scale reads and have high availability, backup and restore features, supports Sets and Sorted Sets cluster mode disabled: one shard - node group (all nodes have all the data, 1 primary and upto 5 replica) horizontal scaling by adding new read replicas, vertical by changing node type (internally create a new node group, then data replication, than DNS update) cluster mode enabled: data is partitioned into shards (up to 500 nodes per cluster, 500 shards with single master, or 250 shards with 1 master and 1 replica). scaling has two modes: online scaling (no downtime, some degradation in performance), offline scaling (unable to serve during backup and restore, changing node type). horizontal scaling: Resharding (scale out/in by adding/removing shards) and Shard Rebalancing (equally distribute the keyspaces among the shards) can be online or offline scaling vertical scaling (change node type) can be done as online scaling

To test connection from EC2 you use use Primary endpoint (not Node Endpoint):

redis-cli -h gofordesi-redis.nivmdy.ng.0001.use1.cache.amazonaws.com ping
PONG

Redis metrics to monitor:

Evictions: the number of non-expired items the cache evicted to allow space for new writes (memory is overfilled)
CPUUtilization: solution to high cpu is to scale up to larger node, or scale out to adding more nodes
SwapUsage: should not exceed 50MB otherwise use more memory
CurrConnections:
DatabaseMemoryUsagePercentage:
NetworkBytesIn
ReplicationBytes, ReplicationLag:

Memcached: multi-node for partitioning of data (sharging, split data), no high avilability (reprication), non persistent, no backup and restore, multi-threaded architecture horizontal scaling: adding new nodes, auto-discovery allow the app to find nodes scale vertical: change node type, they start blank since there is no restore Memcached metrics to monitor:

Evictions
CPUUtilization
SwapUsage
CurrConnections
FreeableMemory

Amazon CloudWatch

CloudWatch is a service for monitoring metrics and logs. Basic monitoring is collecting every 5 minutes, detailed monitoring is paid and it collects every 1 min. It includes: CPUUtilization (processing power), NetworkIn/NetworkOut, DiskReadOps/DiskWriteOps, DiskReadBytes/DiskWriteBytes (only when disk is attached, not for ebs), CPUCreditUsage 1 cpu running 100% for 1 minute. Metrics belong to namespaces and can have up to 30 dimensions per metric (environment, instance id). Dashboards are global and can include metrics from different AWS accounts and regions. You can change time zone and set up auto refresh. Sharing to outside using SSO provider Amazon Cognito. 3 dashboards up to 50 metics for free. $3/dashboard/month afterwards.

You can push custom metrics, for example RAM or from application, every second if you want. Two weeks in the past and two hours in the future is accepted for a timestamp value. You can use PutMetricData API to send data using cli, you can test using cloud shell

aws cloudwatch put-metric-data --metric-name Buffers --namespace MyNameSpace --unit Bytes --value 231434333 --dimensions InstanceId=1-23456789,InstanceType=m1.small
# after 5 minutes
aws cloudwatch put-metric-data --metric-name Buffers --namespace MyNameSpace --unit Bytes --value 231434333 --dimensions InstanceId=1-23456789,InstanceType=m1.small

or an Unified Cloudwatch agent installed with AWS System Manager Agent SSM agent). Example for memory util https://dev.to/drewmullen/send-memory-utilization-metrics-to-cloudwatch-5g28

procstat Plugin for CWAgent can collect specific proccess CPU time, memory. Prefix is procstat_cpu_time, procstat_cpu_usage.

You can also export data using GetMetricData API.

https://explore.skillbuilder.aws/learn/course/external/view/elearning/203/introduction-to-amazon-cloudwatch You can create alarm from EC2 instance -> right click -> Manage cloudwatch alarm

Log groups (arbitrary name, eg application name), log stream (instances within application), can define log expiration policies (7 day expiration since we pay for cw logs storage).

Logs are received from sdk, Cloudwatch Unified Agent, each AWS service.

Logs exports can be send to S3, Kinesis Data Streams, Kinesis Data Firehose, AWS Lambda, Amazon OpenSearch. 12h to be exported.

Using a custom metrics, CloudWatch filter and CloudWatch alarm you can get notification when it is triggered more than 5 times per minute.

Amazon Cloudwatch Logs Insight perform queries and search and analyze logs interactively.

Cloudwatch Alarms are used to trigger notification for any metric, It can be in 3 states: OK, INSUFFICIENT_DATA, ALARM. Period is length of time in seconds to evaluate the metrics. Instead of sns notification we can trigger Reboot EC2 instance, trigger autoscaling action.

CloudWatch Composite Alarm monitors states of other alarms. Helpfull to reduce alarm noise eg skip high CPU when there is a high Network.

Manually trigger alarm

aws cloudwatch set-alarm-state --alarm-name "myalarm" --state-value ALARM --state-reason "testing purposes"

EC2 Status Check metrics:

instance status: your individual instance (StatusCheckFailed_Instance) incorrect networking or startup conf, exhausted memory, corrupted file system. You need to reboot with new conf.
system status: AWS system or hardware on which the instance runs (StatusCheckFailed_System, StatusCheckFailed) loss of network connectivity, system power, software or hardware issues on physical host. You can move to the new host (if you used EBS) or wait for AWS to fix the issue

EC2 Instace Recovery will keep same ip addresses.

For Load balancer you can use: RequestCount, HealthyHostCount, UnHealthyHostCount, TargetResponseTime, HTTP status codes https://docs.aws.amazon.com/elasticloadbalancing/latest/classic/elb-cloudwatch-metrics.html

Event bridge is serverless event bus used to build event driven apps. You can receive webhook on API Gateway which uses lambda to put event on EventBridge which is using another lambda to put message to CloudWatch logs stream. For example S3 Event notification (create object) can trigger stream. Amazon EventBridge Overview and Integration with SaaS Applications https://explore.skillbuilder.aws/learn/course/119/play/457/amazon-eventbridge-overview-and-integration-with-saas-applications Amazon EventBridge is similar to Cloudwatch Events (deprecated), but with more features. You can schedule automated snapshot of ebs. Default Event Bus (generated by AWS services, CW events), Partner Event Bus (receive events from SaaS service), Custom Event Buses (our own apps)

Amazon EventBridge Schema Registry gives the structure of the data. Amazon EventBridge Resource-based Policy manage permissin for specific Event Bus so we can allow PutsEvents from 3-th party accounts.

CloudWatch ServiceLens integrate health info in one place. Also integrates with Synthetics. It integrates with AWS X-Ray to pinpoint performance bottleneck. X-Ray is used for understading dependencies in microservice architecture, service graph.

CloudWatch Synthetics, to monitor API from outside-in using canaries: scripts that run on a schedule, written in Node.js or Python. Canaries offer access to headless Google Chrome via puppeteer or selenium webdriver. https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/CloudWatch_Synthetics_Canaries_Create.html

ClodWatch Synthetics Canary Blueprints:

Heartbeat Monitor: load URL store screenshot and http archive file
API Canary: test basic read and write function of REST APIs
Broken Link Checker: check all links inside the URL that you are testing
Visual Monitoring: compare a screenshot take during a canary run
Canary Recorder: used with CloudWatch Synthetics Recorder to record your actions and automatically generates a script for that
GUI Workflow Builder: verifies that actions can be takeon on your webpage, eg test login form

The AWS Health Dashboard is the single place to learn about the availability and operations of AWS services. It displays relevant and timely information to help users manage events in progress, and provides proactive notifications to help plan for scheduled activities

AWS Systems Manager SSM

It is a free service. https://explore.skillbuilder.aws/learn/course/456/play/1308/aws-systems-manager Run command, state manager, inventory, patch manager, automation, explorer, Parameter Store, session manager (ssh), OpsCenter AWS Systems Manager gives you visibility and control of your infrastructure on operational data from multiple AWS services and allows you to automate operational tasks across your AWS resources.

To install SSM follow https://docs.aws.amazon.com/systems-manager/latest/userguide/systems-manager-setting-up-ec2.html and create SSMInstanceProfile (this name from docs so we will use it) with AmazonSSMManagedInstanceCore policy.

When creating a EC2 instance you need to attach created ec2 instance profile SSMInstanceProfile. For existing ec2, you can also attach/replace IAM Role SSMInstanceProfile, and it will be automatically recognized with the Session Manager. You can activate hybrid intance with script.

It is usefull to remotelly run commands without need to open inbound ssh ports, and you can control which commands can be performed and it is auditable. Free service.

Command for cpu stress is:

sudo amazon-linux-extras install epel -y
sudo yum install stress -y
stress --cpu 1 --timeout 10m

You can see that it is working by clicking on “Public IPv4 address” or “Public IPv4 DNS” and removing “s” from “https://”.

To connect you can use

export PEM_FILE=~/config/keys/pems/2022.pem
export SERVER_IP=174.129.128.6
ssh -i $PEM_FILE ubuntu@$SERVER_IP
ssh -i $PEM_FILE ec2-user@$SERVER_IP

curl $SERVER_IP

To connect without asking for password and not using PEM you can ssh-copy-id but manually

scp -i $PEM_FILE ~/.ssh/id_rsa.pub ubuntu@$SERVER_IP:
ssh -i $PEM_FILE ubuntu@$SERVER_IP
cat id_rsa.pub >> .ssh/authorized_keys && rm id_rsa.pub
exit

SSM Run command

Documents can be: Managed (predefined) or custom documents (can be versioned). Command is set of actions, document, targets and run time paramaters. Use case:

monitoring
bootstrap scripts (user data) ``` #!/bin/bash
use Amazon linux AMI

yum update -y yum install httpd -y echo “hello from $(hostname -f)” > /var/www/html/index.html systemctl start httpd

automatically start on reboot

systemctl enable httpd

on Amazon linux ami you should use service instead systemctl

service httpd start


Inside the machine you can find user script on

cat /var/lib/cloud/instance/cloud-config.txt

Look for logs on

cat /var/log/cloud-init-output.log

To see error in custom schema

cloud-init schema –system

## SSM Automation

It uses Automation Runbook (SSM Documents of type Automation).
Can be triggered manually, EventBridge, on a schedule, by AWS Config
Use case: Restart instance, create an AMI, EBS snapshot...

## SSM Session manager

Another way to connect is using AWS Systems manager > Fleet manager
https://us-east-1.console.aws.amazon.com/systems-manager/managed-instances?region=us-east-1
EC2 need to create a role with `AmazonSSMManagedInstanceCore` policy (deprecated
policy is AmazonEC2RoleforSSM). In tutorials it is called instance profile so
put a name for a role `SSMInstanceProfile` and attach role to existing or new
ec2. No need for ssh keys nor open ports, you can use web or aws cli just
download and install session manager plugin with `sudo
./sessionmanager-bundle/install -i /usr/local/sessionmanagerplugin -b
/usr/local/bin/session-manager-plugin `
https://docs.aws.amazon.com/systems-manager/latest/userguide/session-manager-working-with-install-plugin.html#install-plugin-macos

aws ec2 describe-instances –query “Reservations[].Instances[].InstanceId”

get instance id “i-0f3dde08ce455a628”

aws ssm start-session –target “i-0f3dde08ce455a628”

CloudTrail can intercept StartSession events if you need for compliance.
You can also restict to specific tags for other users, for example use policy
that permits `sssm:StartSession` Action with Condition StringLike
`"ssm:resourceTag/Environment": ["Dev"]`
Session log data can be sent to s3 or CloudWatch logs.
Preferences are on this tab
https://us-east-1.console.aws.amazon.com/systems-manager/session-manager/preferences

## SSM parameter store

It is used for configurations.
It stores passwords in plain text, so for passwords usually we use Secrets
Manager and we can also access them through name
`/aws/reference/secretsmanager/secret_ID_in_Secrets_Manager`
We also have data like
`/aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-x84_64-gp2` public

It is free for max 10_000 parameters, and max 4KB size.
$0.05 for new advanced parameter per month (max 8KB, and max 100_000 total) and
can be attached with Parameter Policy like expiration: EventBridge will receive
notification 15 days before password expires

Name `/my-app/dev/my-db-url` with value `some url` and one encrypted
`/my-app/dev/redis-password` with value `encripted***` you can use cli to access
them (and decrypt if you have access to key store)

aws ssm get-parameters –names /my-app/dev/db-url /my-app/dev/redis-password –with-decryption

aws ssm get-parameters-by-path –path /my-app/ –recursive

## AWS Secrets Manager

It force rotate passwords, database credentials, api keys.
It can store binaries.

## SSM State manager

Automate the process of keeping instances in state that you define.
Use case: bootstrap instance with software, updates on a schedule.
State manager association: defines the state we want.

## SSM Patch manager

Automates the patching managed nodes with security updates, for OS and
application.
Patch manager use patch baseline id so you can use SSM Run command to patch
speficic path groups.

SSM Maintenance windows: defines a schedule, duration, set of registered
instances, set of registered tasks.

# S3

Objects storage (flat storage and each object has uuid) Scallable Simple Object
Storage S3. Buckets reside in region, but the name should be uniq across all
buckets. It looks like that S3 is global service, but not, it is region based,
and you need to choose in which region to put a bucket.

Usage case is for: backups (EBS snapshot), media hosting, static websites.
User can create up to 100 buckets (or 1000 by submitting a service limit
increase). Bucket name should be uniq across all accounts. When deleted the name
is available after 24 hours. Name is between 3-63 characters long
Consist only of lowercase letters, numbers, dots (.), and hyphens (-)
Start with a lowercase letter or number
Not begin with xn-- (beginning February 2020)
Not be formatted as an IP address. (i.e. 198.68.10.2)
Use a dot (.) in the name only if the bucket's intended purpose is to host an
Amazon S3 static website; otherwise do not use a dot (.) in the bucket name
since SSL wild card certificate will work for
https://my.bucket.s3.us-east-1.amazonaws.com/my-file.txt
Virtual hosted-style URL https://bucket-name.s3.Region.amazonaws.com/key-name
Path style URL https://s3.Region.amazonaws.com/bucket-name/key-name is
deprecated.
MAX object size is 5TB (upload using console is 160GB). Number of objects is
unlimited.
For upload bigger than 100MB it is recommended (bigger than 5GB required) to use
multipart upload and AbortIncompleteMultipartUpload lifecycle rule
https://docs.aws.amazon.com/AmazonS3/latest/userguide/mpuoverview.html
Objects consits: key (uniq in bucket), version ID, value, access control info
and metadata (like key value pairs, for example content-type, can not be changed
once object is created).
You can use ap to 10 tags key value pairs to each object (128 unicode chars for
key, and 256 chars for value).
Delete key myfile will permanently remove the object if version is not enabled.
If version is enabled, then delete key myfile will add a mar

https://my-bucket-name.s3.amazonaws.com/some/key-for-file.jpg
htpps://my-bucket-name.s3-us-east-1.amazonaws.com/some/key-for-file.jpg
(deprecated http:s//s3-us-east-1.amazonaws.com/my-bucket-name/key-for-file.jpg)

S3 supports resource based access control: using bucket policy or using Access
control list ACL on object or bucket level.
Also supports user based access control.

To enable static website hosting, you need to:
* enable static web hosting in bucket properties
* disable "Block public access" for the bucket (also on account level if needed)
* write bucket policy to grant public read access, update `Bucket-Name` with
  your bucket name

{ “Version”: “2012-10-17”, “Statement”: [ { “Sid”: “PublicReadGetObject”, “Effect”: “Allow”, “Principal”: “”, “Action”: [ “s3:GetObject” ], “Resource”: [ “arn:aws:s3:::Bucket-Name/” ] } ] }

* if bucket contains objects that are not owned by the bucket owner, you
  need object ACL access control list that grants everyone read access

Bucket policy is used to: grant public access to the bucket, force objects to be
encrypted at upload, grant access to another account (cross acount, for example
you do not have access to another user account, just put its arn in Principal).
You can track costs by using AWS generated tag for cost allocation. This tag
will appear in AWS Cost explorer, AWS Budgets (can send alarms for usage
limits), AWS Cost and usage report.

https://docs.aws.amazon.com/cli/latest/userguide/cli-services-s3-commands.html

make bucket

aws s3 mb s3://mybucket

copy local file upload

aws s3 cp local-file s3://mybucket

list all buckets

aws s3 ls

list all files from bucket

asw s3 ls s3://mybucket

To move data you should use Aws DataSync (migrating by syncing, not one step),
DataSync can sync with S3, EFS, FSx, keeps file permissions and metadata. Agent
is running on schedule, daily weekly. Problem could be a slow internet
connection. Transfer Family is used when copying using network takes more than a
week, so we get a device with agent preinstalled, which pull the data into local
storage and than we ship the device to aws. Sync can be between different
services, or between different cloud providers.
For offline: Snowcone (hdd), snowball edge (ssd) and snowmobile (for exabytes).
Most cost optimal is to transfer on premises data to multiple Snowball edge
storage optimized devices and copy to Amazon S3 and create lifecycle policy to
transition the data into AWS Glacier Currently, there is no way of uploading
objects directly to S3 Glacier using a Snowball Edge.
https://aws.amazon.com/blogs/storage/using-aws-snowball-to-migrate-data-to-amazon-s3-glacier-for-long-term-storage/
AWS SMS server migration service does not have relation to shownball edge
(distractor).
For streaming use Amazon Kinesis Data Streams and Firehose.

For hybrid service you can use Aws Direct Connect (dedicated network connection
to AWS from on premise center) or AWS Storage gateway (used to connect data, ie
store on premise-data in an existing amazon S3 bucket, ie mount as NTF which
uses s3 file gateway - it is using s3 to store, but also the cache for local
most used files).
Those can not extend the VPC network. Use case could be: disaster recovery,
backup, tiered storage, on-premises cache and low-latency file access.


Amazon FSx is service to launch high performance file system to aws, for example
smb or ntfs, and it is backedup daily to s3.
FSx for Lustre (linux cluster) for machine learning, high performance computing
hpc (ssd, hdd options) can be used on premises through vpn or direct connect.

AWS Outposts is service that offers the same AWS infrastructure to any
datacenter, so you can extend your VPC into the on-premises data center, and you
can communicate with private ip addresses.

To avoid internet you can use VPC Endpoints.

Security mechanisms for bucket.
Newly created bucket can only be accessed by the user who created it or the
account owner. Other users can access using:
* AWS IAM: use IAM policy for your users accessing your S3 resources (does not
  have principal)

{ “Version”: “2012-10-17”, “Statement”: [ { “Sid”: “VisualEditor0”, “Effect”: “Allow”, “Action”: “s3:ListBucket”, “Resource”: “arn:aws:s3:::my-trk-bucket” } ] }

* Access control list ACL on individual objects (deprecated)
* Pre-signed URL: grant for limited time, note that presignigning can be
  successfully but actuall access will not work if credentials used in presign
  proccess does not have permission to read the object. If you used Security
  Token Service, presigned URL will expire when token expires.

# this is default signature version so no need to set, max 7 days # aws configure set default.s3.signature_version s3v4 aws s3 presign s3://my-trk-bucket/README.md –expires 60 curl “https://my-trk-bucket.s3.us-east-1.amazonaws.com/README.md?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIARYNKJHQQAVHT4P5Q%2F20220706%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20220706T064501Z&X-Amz-Expires=60&X-Amz-SignedHeaders=host&X-Amz-Signature=2ff3afb8b8e0dcc308aaca2e49c94db3c83feaa26675ec35f4d29a47e4e8d7ae”

Storage classes:
Default is S3 standard tier. There is S3 IA or one zone IA (infrequent access)
you are charged for 128KB for object smaller than 128KB, or for 30days if you
remove before 30days). Use case is backup.

Use Intelligent-Tiering Archive configurations under Properties tab on bucket,
to minimize the cost: Archive Access tier (90days min, minutes to retrieve up to
5 hours) or Deep archive access tier (180 days min, up to 5 hours to retreive).
Object smaller than 128KB are always in frequent access tier.

Glacier Instant retrieval (milisecond retrival, access once a quarter, min 90
days), Glacier Flexible retrieval (retrieval 1min to 12 hours), Glacier Deep
Archive (access once or twice in year, retrieval 12-48hours) min 180days.
You need to initiate a restore and you can use `s3:ObjectRestore:Completed`
event to send notification (you need to update SNS topic so s3 can send this).

For data that is not often accessed but requires high availability choose Amazon
S3 standard IA.

Durability is 11 nines, 99,999999999%, loss of 1 object for 10.000.000 objects
every 10.000 years. That is the same for all storage classes
Availability is 99.99% for s3 standard ie 53min a year. S3 Standard IA is 99.9%
availability.

Cost includes https://aws.amazon.com/s3/pricing/
* storage price: based on storage class, eventual monthly monitoring fee
* request and data retrieval: every api/sdk call
* data transfer: price for bandwith in and out of s3, except data transferred in
  from the internet (upload), data transferred out to EC2 in the same region as
  bucket, data transferred out to cloudfront
* management and replication: price for features like S3 inventory, analytics,
  object tagging

Enable bucket logs under Properties -> Server access logging, you can add
prefix. It will log all GET requests, API calls.
https://docs.aws.amazon.com/AmazonS3/latest/userguide/LogFormat.html
It is advisable to create lifecycle rule under Management, to clear old logs.
Use Athena to serverless query logs
https://aws.amazon.com/premiumsupport/knowledge-center/analyze-logs-athena/
Create report with Amazon Quicksight to create Business intelligence BI
dashboard.
Use Glue service to convert csv to Apache Parquet or ORC, so data is stored as
columnar data for cost saving (less scan). Use larger files > 128 MB.

Object Lock using a write-once-read-many WORM model to prevent object from being
deleted or overwritten. It can be enabled only during bucket creation. It
enables versioning. You can configure Default retention mode so no users (or
governance users) can delete or overwrite during that period (for example 1year)

S3 replication Cross-region replication CRR (use case: low latency, compliance),
Same-region replication SRR (log aggregation, live reproduction prod to test)
Replication works only for new objects, for existing objects you need to use s3
batch replication

S3 object encryption: Server-side encryption sse is default, with sse-s3 key(you
do not have access to the key, header: x-amz-server-side-encryption": "aes256")
but you can use kms key sse-kms (you can see logs in cloudtrail, header:
"x-amz-server-side-encryption": "aws:kms", you need to have access to kms key
and kms limits are applied) or customer provided keys sse-c (we pass the key in
header for each requests, when reading we need to send same key in header).
Client-side encryption (data is encrypted before sending to s3).

Encryption in flight ie encryption in transit ssl/tls.

Cross-origin resource sharing CORS , origin = scheme (protocol) + host (domain)
+ port. Web browsers mechanism to allow visiting other origins, only if other
origin allow the request using CORS header Access-Control-Alow-Origin Browser
sends `OPTIONS / Host: www.other.com Origin: www.main.com`, and we need to
enable CORS for specific origin or for all origins.  CORS can not prevent
scripts to download files, it is only a webbrowser security.
https://docs.aws.amazon.com/AmazonS3/latest/userguide/ManageCorsUsing.html

[ { “AllowedHeaders”: [], “AllowedMethods”: [ “GET” ], “AllowedOrigins”: [ “*” ], “ExposeHeaders”: [] } ]

# Amazon Cloudfront

Cloudfront is content delivery network CDN.
400 point of presence in Global Edge network which are caching content and which
are connected using aws backbone network
https://aws.amazon.com/blogs/networking-and-content-delivery/400-amazon-cloudfront-points-of-presence/

Difference with S3 Cross Region Replication CRR is that cloudfront is good for
static files (TTL is a few days) available everywhere. CRR must be setup for
each region, and files are upding in near real-time so good for dynamic content.

When you enable Cloudfront, you do not need to enable public access for your
bucket, but you need to attach policy that give access to Cloudfront.

You can use AWS Certificate Manager to obtain ssl certificates.

You can enable Geographic Restrictions, and select countries in which your
content is available.

Access Logs can generate reports on: Cache Statistics, popular objects, top
referrers, usage, viewers.

Error codes from origin server 5xx or from S3 4xx are cached also, for example
user do not have access to the underlying bucket 403, or object not found 404.

Cache based on Headers, Session Cookies, Query String Parameters.
Expires or better is Cache-Control: max-age header.

AWS Global Accelerator is a networking tool, so when network is congested, is
optimizes the path to application.

# AWS CloudTrail

Track all user activity across your AWS accounts, see actions that user, role or
service has taken.
Inspect logs with CloudWatch Logs or Athena
https://docs.aws.amazon.com/athena/latest/ug/cloudtrail-logs.html
For example find who when how deleted a.csv

SELECT * FROM “s3_access_logs_db”.”mybucket_logs” WHERE key = ‘a.csv’ AND operation LIKE ‘%DELETE%’ limit 10;

Find sum uploaded files from IP 188.2.98.99 and last month

SELECT SUM(bytessent) as uploadTotal FROM s3_access_logs_db.mybucket_logs WHERE RemoteIP=’188.2.98.99’ AND parse_datetime(RequestDateTime, ‘dd/MMM/yyyy:HH:mm:ss Z’) BETWEEN parse_datetime(‘2022-06-06’, ‘yyyy-MM-dd’) AND parse_datetime(‘2022-07-07’, ‘yyyy-MM-dd’);

Difference between server logs and cloudtrail (service for tracking API usage)
https://docs.aws.amazon.com/AmazonS3/latest/userguide/logging-with-S3.html
* server access logs delivers within a few hours, cloudtrail in 5min for data
  and 15min for management events
* cloudtrail is guaranteed and can be enabled on account, bucket or object level
  and can deliver logs to multiple destinations, and does not log authentication
  failures (but AcceessDenied is logged), json format.

When using a tags, you can write access policy with condition key
"s3:ExistingObjectTag/<key>": "<value>"

{ “Statement”: [ { “Effect”: “Allow”, “Action”: “s3:GetObject”, “Resource”: “arn:aws:s3:::photobucket/*”, “Condition”: { “StringEquals”: { “s3:ExistingObjectTag/phototype”: “finished” } } } ] }

also you can use tags in lifecycle rules, or cloudwatch metrics or croudtrail
logs.

To list all files, you can use API, but that could be expensive if there are a
lot of object. Instead you can enable Management -> Inventory service which will
periodically create cvs file in another bucket that you can query using Amazon
S3 Select (only SELECT command on csv json files) Note it has to be in one line

SELECT * FROM s3object s WHERE s._ 1 = ‘a’ LIMIT 5

https://docs.aws.amazon.com/AmazonS3/latest/userguide/s3-glacier-select-sql-reference-select.html
or Athena.

S3 event notification can be used to call lambda, sns or sqs service when some
api call occurs.

Amazon Simple Queue Service (SQS) is a fully managed message queuing service
that enables you to decouple and scale microservices, distributed systems, and
serverless applications. SQS eliminates the complexity and overhead associated
with managing and operating message-oriented middleware and empowers developers
to focus on differentiating work.
Used for asynchronous integration between application components

Cloudtrail log file integrity validation can be used for audit.

# AWS Config

AWS config (service that track configurations of resources) can be used to make
a sns notification when for example bucket become public using a managed rule
*s3-bucket-public-read-prohibited* also used to enable security and regulatory
compliance.
It can also prevent users for using other (unapproved) AMIs.
https://aws.amazon.com/blogs/security/how-to-use-aws-config-to-monitor-for-and-respond-to-amazon-s3-buckets-allowing-public-access/
Similar tools that check public access is enabled are:
* Aws IAM Access Analyzer - check bucket policy ACL, access point policy, IAM
  roles, KMS keys, Lambda, SQS queues, Secrets Manager Secrets... any
  resource that can be accessed externally, that is outside of Zone of Trust (eg
  AWS Organization) for example Principal is "*".
* AWS Trusted Advisor - check S3 bucket permissions, other Trusted advisor
  checks can include: Cost Optimization, Performance, Security, Fault Tolerance,
  Service Limits. For example security group created by Directory Service should
  not have unrestricted access. Approaching limits.
  Also Cost optimization, under utilized EBS volumes, idle load balancers.
  Trus Advisor is free for core checks.

IAM Security Tools like IAM Credentials Report (account-level, download csv when
keys were used) and IAM Access Advisor (user-level) you can see which service is
used and identify unnecessary permissions that have been assigned to users.

Use S3 Storage Lens to optimize cost.

# AWS Directory Service

Managed microsoft active directory

# ECS

ECS backplane is communicating with ECS agent for placement decision.
Cluster is a logical group of EC2 instances on which Task is run. Task could be
running on EC2 or Fargate. Task can contain one or more container (usually
second is only for logging), defined in Task Definition (blueprint): which
images url and configuration.
Service is for long running applications, is a group of Tasks.

Task definition

{ “containerDefinitions”: [ { “name”: “simple-app”, “image”: “httpd:2.4:, “cpu”: 256, # 1 virtual CPU is 1024 units. Also “0.25 vCpu” “memory”: 300, “ “512 MB, 1 GB” “portMappings”: [ { “hostPort”: 80, “coitnanerPort”: 80, “protocol”: “tcp” } ], “essential”: true }, { “name”: “busybox”, “image”: “busybox”,

}   ] } ```

aws ecs create-task
aws ecs create-service
aws ecs run-task  --launch-type=FARGATE

Task placement: satisfy CPU, memory and network… than other constraints and strategies: Location AZ us-east-1d, which instance type t2.small, Strategies: Binpack (minimize number of EC2 instances, choose instance with the least amount of memory or CPU, and all other tasks will be deployed there) Spread (evenly on all ec2). Constraints: Affinity

TODO: https://ecsworkshop.com/introduction/ecs_basics/task_definition/

EKS

Control-plane nodes: controller manager, cloud controller, scheduler and API server that exposes Kubernetes API Etcd: key value store Worker nodes: Pod (group of one or more containers) similar to Task in ECS, created from PodSpec. Runtime (Docker or containerd), kube-proxy and kubelet

AWS Elastic beanstalk

AWS Service Catalog is to manage infrastructure as code (IaC) templates, so user do not need to know each aws service, then do not even need to be logged in to aws. TagOptions can be applies so they user the same tags. AWS Elastic beanstalk is for deploys web applications. https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/ruby-rails-tutorial.html#ruby-rails-tutorial-launch Each Beanstalk environment will generate: ec2, ALB, S3, ASG, CW alarm, CloudFormation stack and domain name.

AWS CloudFormation

Use it to deploy to multiple AWS Regions quickly, automatically, and reliably. Use a template json file and create a stack.

Download templates https://github.com/jsur/aws-cloudformation-udemy/tree/master/1-introduction

---
Resources:
  MyInstance:
    Type: AWS::EC2::Instance
    Properties:
      AvailabilityZone: us-east-1a
      ImageId: ami-a4c7edb2
      InstanceType: t2.micro

You can upload template using cli aws cloudformation create-stack help for example

# create
aws --profile 2022trk cloudformation create-stack --stack-name myteststack --template-body file://terraform/ec2.cloudformation.yml --parameters ParameterKey=KeyName,ParameterValue=2022

# list only CREATE_COMPLETE
aws --profile 2022trk cloudformation list-stacks --stack-status-filter CREATE_COMPLETE UPDATE_COMPLETE

# describe to find output
export PEM_FILE=~/config/keys/pems/2022.pem
export SERVER_IP=$(aws --profile 2022trk cloudformation describe-stacks --stack-name myteststack --query 'Stacks[0].Outputs[?OutputKey==`ServerIP`].OutputValue' --output text)
ssh -i $PEM_FILE ec2-user@$SERVER_IP sudo cat /var/log/cloud-init-output.log

# update
aws --profile 2022trk cloudformation update-stack --stack-name myteststack --template-body file://terraform/ec2.cloudformation.yml --parameters ParameterKey=KeyName,ParameterValue=2022

# destroy
aws --profile 2022trk cloudformation delete-stack --stack-name myteststack

There are over 224 resource types, type identifiers is: service-provider::service-name::data-type-name for example AWS::EC2::Instance https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-ec2-instance.html

Parameters can be: String, Number, CommaDelimitedList, List, AWS Parameter and it can contain Constraints, AllowedValues, AllowedPattern.

---
Parameters:
  SecurityGroupDescription:
    Type: String
    Description: Security Group Description

Use function !Ref MyParameter (or "Fn::Ref": in separate line). When we !Ref parameter then it returns paratemer value, and when we !Ref some resource then it returns physical ID of the underlying resource. You can "Fn::GetAtt": to get attributes of the resources using dot syntax

NewVolume:
  Properties:
    AvailabilityZone:
      !GetAtt EC2Instance.AvailabilityZone

There is also Fn::GetAZs: !Ref "AWS::Region" which will return a list of all AZs so you can pick first using !Select

You can create a string using join and delimiter

!Join [ ":", [ a, b, c ] ]
# => "a:b:c"

Substitute values

!Sub
  - String # which contains ${VariableName}
  - { VariableName: VariableValue }

Pseudo parameters:

AWS::AccountId example value 123456789012
AWS::NotificationARNs {arn:aws:sns:us-east-!:123456789012:MyTopic}
AWS::Region example us-east-1
AWS::StackId and AWS::StackName

Mappings are fixed variables (region, az, ami, environment like dev/prod)

Mappings:
  RegionMap:
    us-east-1:
      "32": "ami-a4c7edb2"
      "64": "ami-a4c7edb2"

Syntax is !FindInMap [ MapName, TopLevelKey, SecondLevelKey ] Example use !FindInMap [RegionMap, !Ref "AWS::Region", 32]

Outputs are used to link with other Stack (you can not delete a stack if its outputs are being referenced by another stack). You can find return values in docs https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-ec2-instance.html#aws-properties-ec2-instance-return-values

Outputs:
  StackRef:
    Value: !Ref myStack

  ServerIP:
    Description: Server IP address
    Value: !GetAtt MyInstance.PublicIp

  OutputFromNestedStack:
    Value: !GetAtt myStack.Outputs.WebsiteURL

  StackSSHSecurityGroup:
    Value: !Ref MyCompanySSHSecurityGroup
    Export:
      Name: SSHSecurityGroup

Example usage for exported outputs is !ImportValue SSHSecurityGroup

Conditions are used to create based on parameter value or mappings using logic functions: !And, !Equals, !If, !Not, !Or

Conditions:
  CreateProdResources: !Equals [ !Ref EnvType, prod ]

Example usage is in the same level as Type

Resources:
  MountPoint:
    Type: "AWS::EC2::VolumeAttachment"
    Condition: CreateProdResources

You can use cfn-init script instead of UserData since it is more readable. Also to be sure that stack is really working we can use WaitCondition so only after that signal the stack becomes CREATE_COMPLETE. So we use Metadata: and AWS::Cloudformation::Init to define what we want to install and from UserData we call cfn-init for our MyInstance, than call cfn-signal to send signal to WaitCondition. All logs go to cat /var/log/cfn-init.log and /var/log/cfn-init-cmd.log and /var/log/cloud-init.log and /var/log/cloud-init-output.log

Resources:
  MyInstance:
    Type: AWS::EC2::Instance
    Properties:
      UserData:
        !Base64 |
          !Sub |
            #!/bin/bash -xe
            # Get the latest CloudFormation package
            yum update -y aws-cfn-bootstrap
            # Start cfn-init from Metadata
            /opt/aws/bin/cfn-init -s ${AWS::StackId} -r MyInstance --region ${AWS::Region} || error_exit 'Failed to run cfn-init'
            # Start up the cfn-hup daemon to listen for changes to the EC2 instance metadata
            /opt/aws/bin/cfn-hup || error_exit 'Failed to start cfn-hup'
            # All done so signal success
            /opt/aws/bin/cfn-signal -e $? --stack ${AWS::StackId} --resource SampleWaitCondition --region ${AWS::Region}
    Metadata:
      Comment: Install a simple PHP application
      AWS::CloudFormation::Init:
        config:
          packages:
            yum:
              httpd: []
              php: []
          files:
            "/var/www/html/index.html":
              ...
  SampleWaitCondition:
    Type: AWS::CloudFormation::WaitCondition
    CreationPolicy:
      ResourceSignal:
        Timeout: PT1M

  # This will make sure it says CREATE_COMPLETE when all three instances are on
  AutoScalingGroup:
    Type: AWS::AutoScaling::AutoScalingGroup
    Properties:
      DesiredCapacity: "3"
    CreationPolicy:
      ResourceSignal:
        Count: "3"
        Timeout: PT15M

If Wait condition does not receive the required number of signals from ec2 instance than it could be: AMI does not have AWS cloudformation helper script aws-cfn-bootstrap package, inspect logs by disabling rollback on failure (OnFailure=DO_NOTHING option while creating a stack), and check that instance has internet connectivity with curl aws.amazon.com (through NAT if it in private, or Internet gateway it is in public subnet - public means it has a route to IGW in route table anyway)

Rollback means to back to previous known working state (it is was creation than everyting gets deleted) but you can enable option to keep other successfully created resources (after upload the template on Next there is Preserve successfully provisioned resources option)

If someone delete resource, and we update that resource it for some reason update did not succedded, stack will gone into UPDATE_ROLLBACK_FAILED state. We can go to Stack Actions -> Continue update rollback and you can skip that missing resource or manually create it (with the same name) so it ends up in UPDATE_ROLLBACK_COMPLETE state and we can try to update again. We can use drift detection to see if we missed when we manually create the resource. When template is wrong and we want to create a stack than ROLLBACK_COMPLETE is state and we can not update this stack (we can only remove this stack).

Another way to set up dependencies is to use dependon attribute

Resource:
  Ec2Instance:
    DependsOn: MyDB

  MyDb:

Nested stacks is used when you isolate repeated components. We just need a template url and parameters that are used

Resources:
  SSHSecurityGroupStack:
    Type: AWS::CloudFormation::Stack
    Properties:
      TemplateURL: https://s3.amazonaws.com/cloudformation-bucket-common-mycorp/ssh-security-group.yaml
      Parameters:
        ApplicationName: !Ref AWS::StackName
        VPCId: !Ref VPCId
      TimeoutInMinutes: 5

ChangeSets are used to know what changes will be made (still do not know if it will be successfull). Change set is created on web for existing stacks.

Cloudformation drift occurs when someone manually change resources created by cloudformation. Stack actions -> Detect drift.

DeletionPolicy can be Retain (keep), Snapshot (keep the data), Delete (default) when we remove stack.

Resources:
  myS3Bucket:
    Type: AWS::S3::Bucket
    DeletionPolicy: Retain

Beside createpolicy CreationPolicy deletepolicy DeletionPolicy there is also UpdatePolicy which can set AutoScalingRollingUpdate with MinInstancesInService: "1" and MaxBatchSize: "2" so we update 2 and keep 1 (keeps existing auto scalling group). Or there is AutoScalingReplacingUpdate with WillReplace: "true" (create new auto scalling group).

But if you want to prevent Stack to be deleted, you can enable TerminationProtection by Action -> Edit termination protection.

Use StackSet to provision across multiple accounts and regions (for example deploy IAM role in each account). Stack sets requires specific iam roles

Use Stack Policies to determine which resource can be updated. It is defined in separate json file and uploaded on web on Next page while creating stack. Action denied by stack policy error will be shown.

{
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "Update:*",
      "Principal": "*",
      "Resource": "*"
    },
    {
      "Effect": "Deny",
      "Action": "Update:*",
      "Principal": "*",
      "Resource": "LogicalResourceId/MyInstance"
    }
  ]
}

Use resource import to bring existing resource to CloudFormation. Prevent updates to critical resources by using a Stack policy.

AWS LightSail Use pre-configured development stacks like LAMP, Nginx, MEAN, and Node.js. to get online quickly and easily.

AWS Application Discovery Service is used to collect data about the configuration, usage, and behavior of its on-premises data centers to assist in planning a migration to AWS

Amazon Codeguru

Only for Jvm java and python

CDK

https://aws.amazon.com/cdk/ defining Kubernetes configuration in TypeScript, Python, and Java

Practice

acloudgutu courses https://acloudguru.com/learning-paths/aws-devops twich https://aws.amazon.com/training/twitch/ TODO: https://www.twitch.tv/videos/1439636257

https://www.amazon.com/s?k=aws+sysops+administrator+associate&crid=EILDGRZS79N1&sprefix=aws+sysops+admin%2Caps%2C162&ref=nb_sb_ss_ts-doa-p_1_16 https://www.examtopics.com/exams/amazon/aws-devops-engineer-professional/

AWS Certified SysOps Administrator Associate SOA-CO2 Exam guide

monitoring, logging, remediation
reliability and business continuity
deployment, provisioning and automation
security and compliance
networking and content delivery
cost and performance optimization

preparation with AWS Certified Solutions Architect Associate SAA-CO2

SNS can not monitor Cloudwatch

The Well Architected Framework

Set of principles/pillars:

Operational excellence: all operations are code, documentation is updated automatically, make smaller changes you can rollback, iterate and anticipage failure (server down)
security: identities have the least privileges required, know who did what when (traceability), security is woven into the fabric of the system, automate security task, encrypt data in transit and at rest, prepare for the worst
cost optimization: consumption based pricing, measuring efficiency constantly, let aws do the work whenever possible
reliability: recover from issues automatically, scale horizontally first for resiliency, reduce idle resources, manage change through automation
performance efficiency: let aws do the work whenever possible, reduce latency through regions and AWS egde, serverless
sustainability: adopt new more efficient hardware and software offerings

Agility is all about speed (experiment quickly), and not about autoscale or elimination of wasted capacity.

Amazon detective

Intrusion detection using cloudtrail logs, vpc flow logs , amazon guardduty, eks audit logs.

GuardDuty monitors workloads for malicious activity. Amazon GuardDuty is a threat detection service that continuously monitors your AWS accounts and workloads for malicious activity and delivers detailed security findings for visibility and remediation. It is looking for CloudTrail Events Logs, CloudTail Management Events, CloudTrail S3 Data Events (getObject), VPC Flow Logs (unusual IP address), DNS Logs. Public revealed keys. It has dedicated finding for CryptoCurrency attack.

VPC flow logs capture information about ip traffic to and from network interfaces.

Macie is used to detect sensitive data in S3 bucket, eg identify Personally Identifieable Information PII.

AWS Shield is managed DDos protection, enabled for free for each account. AWS Shield Advanced gives 24/7 support and aws bill reimbursement.

AWS Web Application Firewall WAF prevent web application common web exploits, such as bot traffic, sql injection, cross site scripting xss. I can be used to block countries (geo-match), Web access control list ACL rules can also block specific ip, http headers, url strings. WAF is deployed to ALB, API gateway, CloudFront. Penetration Testing, aws customers are welcome to carry out security assessment againts 8 aws services: ec2, rds, cloudfront, aurora, api gateways, lambda, ligtsail, elastic beanstalk. but for other test are profibited: dod, flooding, dns zone walking on route 53.

Amazon Inspector is for automated vulnerability detection. For ec2 identify unintended network access or OS vulnaerability using SSM agent, for ECR assessment of container images, for lambda vulnerabilities in function and package dependencies. Send finding to Amazon Event Bridge. Free for first 15 days.

Amazon DynamoDB

NoSQL database with automatic backup and restore, SLA 99.999%, optimize costs with automatic scales up and down.

AWS Glue

Discover prepare and move from one source for analytics or machine learning.

Amazon EMR

Run apache spark, hive, presto, hadoop,

AWS OpsWorks

Configuration management service to automate operations with chef and puppet. View operational data from multiple AWS services through a unified user interface and automate operational tasks This is alternative to AWS SSM.

AWS CloudSHM

AWS CloudHSM helps you meet corporate, contractual, and regulatory compliance requirements for data security. It uses a highly secure hardware storage device to store encryption keys. KMS is configuring custom key store with cloudhsm.

Artifact

Customers can download AWS compliance documentation and AWS agreements. Compliance portfolio for Payment card industry PCI, Service Organization Control SOC, NDA agreement, HIPPA, audit reports. Can be used to support internal audit or compliance.

Amazon OpenSearch service

Use elasticsearch and kabana to analize log, real-time application monitoring, website search.

AWS Step functions

Visual workflow service that helps developers use AWS services to build distributed applications, automate processes, orchestrate microservices, and create data and machine learning (ML) pipelines.

Amazon SageMaker Build, train, and deploy machine learning (ML) models for any use case with fully managed infrastructure, tools, and workflows

Amazon simple workflow service swf, build apps that coordinate work across distributed components

Support plan

Business support plan includes 24/7 email,chat support Enterprise support plan includes dedicated Technical Account Manager TAM, and Concierge for account issue.

AWS Amplify

Tools that help for full stack web and mobile app, think of it like elastic beanstalk for serverless apps.

AWS Kibana

Does not support IAM users and roles, but supports HTTP Basic authentication, SAML and Amazon Cognito.

Sidekiq_tips

Thu, 05 May 2022 00:00:00 +0200

https://github.com/duleorlovic/sidekiq_tips/#readme

Sidekiq tips

Docs on wiki https://github.com/mperham/sidekiq/wiki

We could use sidekiq as queuing backend for ActiveJob https://github.com/mperham/sidekiq/wiki/Active-Job but since it is slower and sidekiq extension is hard to use, I prefer to use basic sidekiq (outside of ActiveJob).

To install

bundle add sidekiq

and run the main process

sidekiq

You do not need to restart the process when you make changes in jobs. Restart is needed when you make change in sidekiq.yml configuration. You can start both rails and sidekiq in one command using Procfile

# Procfile
web: bundle exec rails s -p 3000
worker: bundle exec sidekiq -C config/sidekiq.yml

and start with

foreman start

Let’s create plain sidekiq job

rails g sidekiq:job a
vi app/sidekiq/a_job.rb

Sidekiq uses syntax https://github.com/mperham/sidekiq/wiki/Scheduled-Jobs similar to ActiveJob perform_later

AJob.perform_later args
AJob.set(wait: 1.week).perform_later args
AJob.set(wait_until: Date.tomorrow.noon).perform_later args
AJob.perform_now args

we have

AJob.perform_async 'duke'
AJob.perform_in 3.hours, 'duke'
AJob.perform_at 3.hours.from_now, 'duke'

# to invoke perform_now use
AJob.new.perform 'duke'

With ActiveJob you can pass entire ActiveRecord objects because GlobalID will deserialize for us. But if you are using directly sidekiq jobs (not inherited from ActiveJob::Base) than you should pass object_id.

Queues

Since the main process will run default queue, I prefer to name the queue based on the app and use that name in configuration. If you run jobs from another app you will get NameError: uninitialized constant ... https://github.com/mperham/sidekiq/wiki/Advanced-Options

# config/sidekiq.yml
---
:concurrency: 2
:queues:
  - my_app_critical
  - my_app_default

In this example my_app_default jobs will be executed only if there is no 2 my_app_critical enqueued jobs. Also note if there are 2 my_app_default running jobs my_app_critical will have to wait them to complete.

Sidekiq supports ordered (like previos example) and weighted modes but you can not mix those to modes. If, for example, you need a critical queue that is processed first, and would like other queues to be weighted, you would dedicate a Sidekiq process exclusively to the critical queue, and other Sidekiq processes to service the rest of the queues.

sidekiq -q critical # Only handles jobs on the "critical" queue
sidekiq -q default -q low -q critical # Handles critical jobs only after checking for other jobs

Redis

You need to install redis server, which is simply adding Heroku redis addon. https://elements.heroku.com/addons/heroku-redis Or on AWS you can install https://www.digitalocean.com/community/tutorials/how-to-install-and-secure-redis-on-ubuntu-18-04 Since it allows only 10 connections you need to limit connections for sidekiq.

Sidekiq server uses two connections, so if :concurrency: 3 than server uses 5 connections so you can use puma threads 5 to utilize all 10 connections. https://github.com/mperham/sidekiq/issues/117 https://manuelvanrijn.nl/sidekiq-heroku-redis-calc/

For error

A Redis::CommandError occurred in background at 2022-07-29 05:55:22 UTC :

  MISCONF Redis is configured to save RDB snapshots, but it's currently unable to persist to disk. Commands that may modify the data set are disabled, because this instance is configured to report errors during writes if RDB snapshotting fails (stop-writes-on-bgsave-error option). Please check the Redis logs for details about the RDB error.
  /Users/dule/.rvm/gems/ruby-3.0.1/gems/redis-4.2.5/lib/redis/client.rb:132:in `call'

you need to restart redis

brew services restart redis

Web UI

https://github.com/mperham/sidekiq/wiki/Monitoring

# config/routes.rb
require 'sidekiq/web'

  mount Sidekiq::Web => '/sidekiq'

# app/views/pages/index.html.erb
<%= link_to "Sidekiq", "/sidekiq" %>

Add back to app button

# config/initializers/sidekiq.rb
require 'sidekiq/web'
Sidekiq::Web.app_url = '/' # show "Back to App" button

https://github.com/mperham/sidekiq/wiki/Best-Practices#4-use-precise-terminology Do not use worker term Job is created when you enqueue a job instance. Process is the main sidekiq command that you started. To see current processes and number of threads http://localhost:3000/sidekiq/busy Busy Thread is created when proccess start executing the job

Job lifecycle https://github.com/mperham/sidekiq/wiki/Job-Lifecycle Final state is either Processed (only counter) or Dead, other states are transitive states (temporary states)

We can use sidekiq_options

# app/sidekiq/a_job.rb
  # Default retry is 25, do not use if job is not idempotent
  sidekiq_options retry: 25
  # will be completely ephemeral, not in Retry or Dead, just increment counters
  sidekiq_options retry: false
  # will go immediately to the Dead tab upon first failure
  sidekiq_options retry: 0

Scheduler

https://github.com/moove-it/sidekiq-scheduler

bundle add sidekiq-scheduler

Create sample scheduler

# app/sidekiq_worker/weekly_remainder_worker.rb
require 'sidekiq-scheduler'

class WeeklyRemainderWorker
  include Sidekiq::Worker
  sidekiq_options queue: 'my_app_default'

  def perform
    puts "WeeklyRemainderWorker finished"
  end
end

add to configuration

# config/sidekiq.yml

:schedule:
  weekly_remainder:
    cron: '0 * * * * *'   # https://crontab.guru/
    class: WeeklyRemainderWorker

add to routes

# config/routes.rb
require 'sidekiq-scheduler/web'

Clear of find a job

To clear see https://gist.github.com/wbotelhos/fb865fba2b4f3518c8e533c7487d5354 To clear all jobs from a current queue named my_app_

# this will not remove scheduled jobs, only enqueued jobs
Sidekiq::Queue.new.clear # this will clear `default` queue
Sidekiq::Queue.new('my_app_default').clear

Sidekiq::ScheduledSet.new.clear

# Reset counters
Sidekiq::Stats.new.reset

To find specific existing jobs you can use scan or map.compact

queue = Sidekiq::Queue.new("default")
# https://github.com/mperham/sidekiq/wiki/API
jobs = queue.map do |job|
  if job.klass == '[JOB_CLASS]'
    {job_id: job.jid, job_klass: job.klass, arguments: job.args}
  end
end.compact

Test background jobs spec

You can not use ActiveJob assertions since we do not use ActiveJob https://api.rubyonrails.org/classes/ActiveJob/TestHelper.html#method-i-assert_enqueued_jobs like assert_enqueued_with job: MyJob, args: [user] perform_enqueued_jobs assert_performed_jobs 1

But you can test using https://github.com/mperham/sidekiq/wiki/Testing

# test/test_helper.rb
require "sidekiq/testing"

and

# test/sidekiq_workers/weekly_remainder_worker_test.rb
    assert_difference "AJob.jobs.size", 1 do
      ScheduleScraperPageWorker.new.perform
    end

Start with rails

Sidekiq 7 enables you to run sidekiq with rails s command

# config/puma.rb
# https://www.mikeperham.com/2022/10/27/sidekiq-7.0-embedding/
workers 2
threads 1, 3

require "sidekiq"
# preloading the application is necessary to ensure
# the configuration in your initializer runs before
# the boot callback below.
preload_app!

x = nil
on_worker_boot do
  x = Sidekiq.configure_embed do |config|
    # config.logger.level = Logger::DEBUG
    config.queues = %w[critical default low]
    config.concurrency = 2
  end
  x.run
end

on_worker_shutdown do
  x&.stop
end

Docker Deployment

Tue, 03 May 2022 00:00:00 +0200

AWS ECS

https://aws.amazon.com/blogs/containers/deploy-applications-on-amazon-ecs-using-docker-compose/

docker context create ecs myecscontext
docker context use myecscontext
docker context ls

# start containers
docker compose up
docker compose -f docker-compose.ecs.yml up

# view exposed port and url like
# http://docke-loadb-rjft57gmmqri-853572988.us-east-1.elb.amazonaws.com
docker compose ps

# remove infrastructure
docker compose down

# remove containers and clear them to free up space
docker system prune -a --volumes

Build and push to ECR https://docs.aws.amazon.com/AmazonECR/latest/userguide/docker-push-ecr-image.html

aws ecr get-login-password --region us-east-1 | docker login --username AWS --password-stdin 219232999684.dkr.ecr.us-east-1.amazonaws.com
docker push 219232999684.dkr.ecr.us-east-1.amazonaws.com/selenium-ssh:strong-password 

Rails Terraform Aws Load Balancer

Mon, 28 Mar 2022 00:00:00 +0200

Introduction

We are using Terraform to provision Loadbalancer and other resources on AWS. First you need to learn Terraform Fundamentals

For AWS, you can start with basic tutorial https://learn.hashicorp.com/collections/terraform/aws-get-started and than invest in advanced tutorials https://learn.hashicorp.com/collections/terraform/aws

We need to ignore terraform internal files, .env and keys

# ignore `.terraform` folders
cat >> .gitignore << HERE_DOC
# ignore terraform folder
.terraform/
.env
# ignore keys in any folder
mykey
mykey.pub
HERE_DOC

Create separate folder for staging and production (it is recommended to have same setup on staging as on production), or you can create folder for each setup

# mkdir terraform_staging
# mkdir terraform_production
mkdir terraform_one_instance
mkdir terraform_load_balancer

Just make sure you cd to that folder when you are using terraform cli

cd terraform_one_instance

First file to look at is terraform_one_instance/main.tf where we define provider config with credentials.

AWS CLI

To authenticate you can use several methods https://registry.terraform.io/providers/hashicorp/aws/latest/docs#authentication-and-configuration One way is to use default config and AWS CLI https://aws.amazon.com/cli/ https://docs.aws.amazon.com/cli/latest/userguide/cli-chap-getting-started.html

If you export keys, cli will use that env variables. To see or update ~/.aws/credentials and ~/.aws/config you can run

aws configure

To list current instances

aws ec2 describe-instances

But I like to use provider configuration since we can see that we need those variables. Anything that could be changed I put inside var.tf For secrets I use .env file. You can load those keys from .env to bash ENV:

env

So for AWS keys we define

# .env
# Load env into current shell with:
# set -o allexport; source .env; set +o allexport
TF_VAR_AWS_ACCESS_KEY=AKIA...

and variable declaration (TF_VAR_{name} is used as {name} variable)

# var.tf
variable "AWS_ACCESS_KEY" {}

and use in aws provider configuration

# main.tf
provider "aws" {
  # comment if you want current `aws configure` to be used
  access_key = var.AWS_ACCESS_KEY
}

Inside main.tf we haveterraform block that defines version of providers and provider block that configures specific provider

# main.tf
terraform {
  # this block is optional
  required_providers {
    # https://registry.terraform.io/providers/hashicorp/aws/latest/docs
    aws = {
      source  = "hashicorp/aws"
      version = "~> 3.0"
    }
  }
}

provider "aws" {
  # comment if you want current `aws configure` to be used
  access_key = var.AWS_ACCESS_KEY
  secret_key = var.AWS_SECRET_KEY
  region     = var.AWS_REGION
}

Maybe the best way is to avoid env variables and use aws profile aws configure --profile 2022trk

# main.tf
provider "aws" {
  profile = "2022trk"
}

File names

We use AWS resources https://registry.terraform.io/providers/hashicorp/aws/latest/docs

Common resources are:

vpc.tf vpc, subnet (a, b), internet gateway and route table, and association between route table and subnets
security_group.tf for ssh, http, ping, mysql access
key.tf to import ssh key

You should organize your modules based on privilege and volatility https://learn.hashicorp.com/tutorials/terraform/pattern-module-creation?in=terraform/modules#network-module

security: IAM
routing: Route53, RouteTable, HostedZone
Network: VPC, NAT gateway, security group
web: LoadBalancer, AutoScalingGroup, S3
app: LoadBalancer, AutoScalingGroup
database: RDS

AMI

name “ubuntu/images/hvm-ssd/ubuntu-focal-20.04-amd64-server-*”

VPC

Find all availability zones

aws --profile=2022trk ec2 describe-availability-zones --query 'AvailabilityZones[].ZoneName'

One instance

For one instance we can use instance.tf

to enable internet for private instances we use nat_gateway resource type (it needs elastic ip) ```
nat.tf

elastic ip is needed for nat gw

resource “aws_eip” “nat” { vpc = true }

resource “aws_nat_gateway” “nat-gw” { allocation_id = aws_eip.nat.id subnet_id = aws_subnet.main-public-1.id depends_on = [aws_internet_gateway.main-gw] }

VPC setup for NAT

resource “aws_route_table” “main-private” { vpc_id = aws_vpc.main.id route { cidr_block = “0.0.0.0/0” nat_gateway_id = aws_nat_gateway.nat-gw.id }

tags = { Name = “main-private-1” } }

route associations private

resource “aws_route_table_association” “main-private-1-a” { subnet_id = aws_subnet.main-private-1.id route_table_id = aws_route_table.main-private.id }


ebs_volume

instance.tf

resource “aws_ebs_volume” “ebs-volume-1” { availability_zone = “eu-west-1a” size = 20 type = “gp2” tags = { Name = “extra volume data” } }

resource “aws_volume_attachment” “ebs-volume-1-attachment” { device_name = “/dev/xvdh” volume_id = aws_ebs_volume.ebs-volume-1.id instance_id = aws_instance.example.id }

user_data is used to do script at launch - creation of instance (not reboot): to
install extra software, join a cluster, mount volumes
Use as string or templates

instance.tf

resource “aws_instance” “example” { ami = var.AMIS[var.AWS_REGION] instance_type = “t2.micro”

# the public SSH key key_name = aws_key_pair.mykeypair.key_name

# user data user_data = data.template_cloudinit_config.cloudinit-example.rendered }

resource “aws_ebs_volume” “ebs-volume-1” { availability_zone = “eu-west-1a” size = 20 type = “gp2” tags = { Name = “extra volume data” } }

resource “aws_volume_attachment” “ebs-volume-1-attachment” { device_name = var.INSTANCE_DEVICE_NAME volume_id = aws_ebs_volume.ebs-volume-1.id instance_id = aws_instance.example.id skip_destroy = true # skip destroy to avoid issues with terraform destroy }

data for scripts

cloudinit.tf

data “template_file” “init-script” { template = file(“scripts/init.cfg”) vars = { REGION = var.AWS_REGION } }

data “template_file” “shell-script” { template = file(“scripts/volumes.sh”) vars = { DEVICE = var.INSTANCE_DEVICE_NAME } }

data “template_cloudinit_config” “cloudinit-example” { gzip = false base64_encode = false

part { filename = “init.cfg” content_type = “text/cloud-config” content = data.template_file.init-script.rendered }

part { content_type = “text/x-shellscript” content = data.template_file.shell-script.rendered } }

scripts

scripts/init.cfg

#cloud-config

repo_update: true repo_upgrade: all

packages:

lvm2

output: all: ‘| tee -a /var/log/cloud-init-output.log’

scripts/volumes.sh

#!/bin/bash

set -ex

vgchange -ay

DEVICE_FS=blkid -o value -s TYPE ${DEVICE} || echo "" if [ “echo -n $DEVICE_FS” == “” ] ; then # wait for the device to be attached DEVICENAME=echo "${DEVICE}" | awk -F '/' '{print $3}' DEVICEEXISTS=’’ while [[ -z $DEVICEEXISTS ]]; do echo “checking $DEVICENAME” DEVICEEXISTS=lsblk |grep "$DEVICENAME" |wc -l if [[ $DEVICEEXISTS != “1” ]]; then sleep 15 fi done # make sure the device file in /dev/ exists count=0 until [[ -e ${DEVICE} || “$count” == “60” ]]; do sleep 5 count=$(expr $count + 1) done pvcreate ${DEVICE} vgcreate data ${DEVICE} lvcreate –name volume1 -l 100%FREE data mkfs.ext4 /dev/data/volume1 fi mkdir -p /data echo ‘/dev/data/volume1 /data ext4 defaults 0 0’ » /etc/fstab mount /data

install docker

curl https://get.docker.com | bash


static public ip and static private ip

instance.tf

resource “aws_instance” “example” { ami = var.AMIS[var.AWS_REGION] instance_type = “t2.micro” subnet_id = aws_subnet.main-public-1.id private_id = “10.0.1.4” # within the range of main-public-1 }

elastic ip address is free when it is assigned to instance, otherwise it is

not free, so better is to use `instance` and assign on create. otherwise you

can assign ip to instance in association aws_eip_association

https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/eip

resource “aws_eip” “example-eip” { instance = aws_instance.example.id vpc = true }

output “public-ip” { value = aws_eip.example-eip.public_ip }

route53 can be used so we use hostname instead of ip address

reute53.tf

resource “aws_route53_zone” “newtech-academy” { name = “newtech.academy” }

resource “aws_route53_record” “server1-record” { zone_id = aws_route53_zone.newtech-academy.zone_id name = “server1.newtech.academy” type = “A” ttl = “300” records = [aws_eip.example-eip.public_ip] }

resource “aws_route53_record” “www-record” { zone_id = aws_route53_zone.newtech-academy.zone_id name = “www.newtech.academy” type = “A” ttl = “300” records = [“104.236.247.8”] }

resource “aws_route53_record” “mail1-record” { zone_id = aws_route53_zone.newtech-academy.zone_id name = “newtech.academy” type = “MX” ttl = “300” records = [ “1 aspmx.l.google.com.”, “5 alt1.aspmx.l.google.com.”, “5 alt2.aspmx.l.google.com.”, “10 aspmx2.googlemail.com.”, “10 aspmx3.googlemail.com.”, ] }

output “ns-servers” { description = “Use this nameservers on your registar” value = aws_route53_zone.newtech-academy.name_servers } output “check-server1” { value = “host server1.newtech.academy ${aws_route53_zone.newtech-academy.name_servers[0]}” }

RDS relation database service: managed database with replication (high
availability), automated snapshots (backups) and security updates, instance
replacement (vertical scaling, for example more memory/cpu)
You need to define: subnet group (to specify in what subnets db will be in),
parameter group (change settings in db since we do not have ssh access to
instances) and security group (firewall to enable incomming traffic)
https://github.com/wardviaene/terraform-course/tree/master/demo-12

rds.tf

resource “aws_db_subnet_group” “mariadb-subnet” { name = “mariadb-subnet” description = “RDS subnet group” subnet_ids = [aws_subnet.main-private-1.id, aws_subnet.main-private-2.id] }

resource “aws_db_parameter_group” “mariadb-parameters” { name = “mariadb-parameters” family = “mariadb10.4” description = “MariaDB parameter group”

parameter { name = “max_allowed_packet” value = “16777216” } }

resource “aws_db_instance” “mariadb” { allocated_storage = 100 # 100 GB of storage, gives us more IOPS than a lower number engine = “mariadb” engine_version = “10.4.13” instance_class = “db.t2.small” # use micro if you want to use the free tier identifier = “mariadb” name = “mariadb” username = “root” # username password = var.RDS_PASSWORD # password db_subnet_group_name = aws_db_subnet_group.mariadb-subnet.name parameter_group_name = aws_db_parameter_group.mariadb-parameters.name multi_az = “false” # set to true to have high availability: 2 instances synchronized with each other vpc_security_group_ids = [aws_security_group.allow-mariadb.id] storage_type = “gp2” backup_retention_period = 30 # how long you’re going to keep your backups availability_zone = aws_subnet.main-private-1.availability_zone # prefered AZ skip_final_snapshot = true # skip final snapshot when doing terraform destroy tags = { Name = “mariadb-instance” } }

securitygroup.tf

https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/security_group

resource “aws_security_group” “example-instance” { vpc_id = aws_vpc.main.id name = “allow-ssh” description = “security group that allows ssh and all egress traffic” egress { from_port = 0 to_port = 0 protocol = “-1” cidr_blocks = [“0.0.0.0/0”] }

ingress { from_port = 22 to_port = 22 protocol = “tcp” cidr_blocks = [“0.0.0.0/0”] } tags = { Name = “example-instance” } }

resource “aws_security_group” “allow-mariadb” { vpc_id = aws_vpc.main.id name = “allow-mariadb” description = “allow-mariadb” ingress { from_port = 3306 to_port = 3306 protocol = “tcp” security_groups = [aws_security_group.example-instance.id] # allowing access from our example instance } egress { from_port = 0 to_port = 0 protocol = “-1” cidr_blocks = [“0.0.0.0/0”] self = true } tags = { Name = “allow-mariadb” } }

IAM identity and access management: user can have groups and roles. user can
login using login/password or token and MFA, and access key and secret key.
You can use predefined policy and attach to group or you add gruop inline policy

iam.tf

group definition

resource “aws_iam_group” “administrators” { name = “administrators” }

resource “aws_iam_policy_attachment” “administrators-attach” { name = “administrators-attach” groups = [aws_iam_group.administrators.name] policy_arn = “arn:aws:iam::aws:policy/AdministratorAccess” # or inline policy = «EOF }

resource “aws_iam_group_policy” “my_policy” {

name = “my_administrator_policy”

group = aws_iam_group.administrators.id

policy = «EOF

{

“Version”: “2012-10-17”,

“Statement”: [

{

“Effect”: “Allow”,

“Action”: “*”,

“Resource”: “*”

}

]

}

EOF

}

user

resource “aws_iam_user” “admin1” { name = “admin1” }

resource “aws_iam_user” “admin2” { name = “admin2” }

resource “aws_iam_group_membership” “administrators-users” { name = “administrators-users” users = [ aws_iam_user.admin1.name, aws_iam_user.admin2.name, ] group = aws_iam_group.administrators.name }

output “warning” { value = “WARNING: make sure you’re not using the AdministratorAccess policy for other users/groups/roles. If this is the case, don’t run terraform destroy, but manually unlink the created resources” }

iam roles
Roles are used to add temporary access that they normally would't have.
Roles can be attached to EC2 instances, from that instance user can obtain
access credentials, using those credentials user or service can assume the role.

s3.tf

resource “aws_s3_bucket” “b” { bucket = “mybucket-c29df1” acl = “private”

tags = { Name = “mybucket-c29df1” } }

instance.tf

resource “aws_instance” “example” { ami = var.AMIS[var.AWS_REGION] instance_type = “t2.micro”

# the VPC subnet subnet_id = aws_subnet.main-public-1.id

# the security group vpc_security_group_ids = [aws_security_group.example-instance.id]

# the public SSH key key_name = aws_key_pair.mykeypair.key_name

# role: iam_instance_profile = aws_iam_instance_profile.s3-mybucket-role-instanceprofile.name }

iam.tf

resource “aws_iam_role” “s3-mybucket-role” { name = “s3-mybucket-role” assume_role_policy = «EOF { “Version”: “2012-10-17”, “Statement”: [ { “Action”: “sts:AssumeRole”, “Principal”: { “Service”: “ec2.amazonaws.com” }, “Effect”: “Allow”, “Sid”: “” } ] } EOF

}

resource “aws_iam_instance_profile” “s3-mybucket-role-instanceprofile” { name = “s3-mybucket-role” role = aws_iam_role.s3-mybucket-role.name }

resource “aws_iam_role_policy” “s3-mybucket-role-policy” { name = “s3-mybucket-role-policy” role = aws_iam_role.s3-mybucket-role.id policy = «EOF { “Version”: “2012-10-17”, “Statement”: [ { “Effect”: “Allow”, “Action”: [ “s3:” ], “Resource”: [ “arn:aws:s3:::mybucket-c29df1”, “arn:aws:s3:::mybucket-c29df1/” ] } ] } EOF

}

autoscalling needs: launch configuration (properties of the instance to be
launched ami id, security group) or launch template () and autoscalling group
(scaling properties like min instances, health check).
https://github.com/wardviaene/terraform-course/tree/master/demo-15

launch configuration and autoscalling group

autoscaling.tf

https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/launch_configuration

resource “aws_launch_configuration” “movebase-launchconfig” { name_prefix = “movebase-launchconfig” image_id = var.AMIS[var.AWS_REGION] instance_type = “t2.micro” key_name = aws_key_pair.movebase-key-pair.key_name security_groups = [aws_security_group.movebase-allow-ssh-and-all-egress.id] }

https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/autoscaling_group

resource “aws_autoscaling_group” “movebase-autoscaling-group” { name = “movebase-autoscaling-group” vpc_zone_identifier = [aws_subnet.movebase-subnet-public-1.id, aws_subnet.movebase-subnet-public-2.id] launch_configuration = aws_launch_configuration.movebase-launchconfig.name min_size = 1 max_size = 2 health_check_grace_period = 300 health_check_type = “EC2” force_delete = true

tag { key = “Name” value = “movebase-ec2-instance” propagate_at_launch = true } }

policy and alarm
autoscalling policy is triggered based on threshold (cloudwatch alarm)

autoscalingpolicy.tf

https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/autoscaling_policy

resource “aws_autoscaling_policy” “movebase-autoscaling-policy-cpu” { name = “movebase-autoscaling-policy-cpu” autoscaling_group_name = aws_autoscaling_group.movebase-autoscaling-group.name adjustment_type = “ChangeInCapacity” scaling_adjustment = “1” cooldown = “300” policy_type = “SimpleScaling” }

https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/cloudwatch_metric_alarm

resource “aws_cloudwatch_metric_alarm” “movebase-cloudwatch-metric-alarm-cpu” { alarm_name = “movebase-cloudwatch-metric-alarm-cpu” alarm_description = “movebase-cloudwatch-metric-alarm-cpu” comparison_operator = “GreaterThanOrEqualToThreshold” evaluation_periods = “2” metric_name = “CPUUtilization” namespace = “AWS/EC2” period = “120” statistic = “Average” threshold = “30”

dimensions = { “AutoScalingGroupName” = aws_autoscaling_group.movebase-autoscaling-group.name }

actions_enabled = true alarm_actions = [aws_autoscaling_policy.movebase-autoscaling-policy-cpu.arn] }

scale down alarm

resource “aws_autoscaling_policy” “movebase-autoscaling-policy-cpu-scaledown” { name = “movebase-autoscaling-policy-cpu-scaledown” autoscaling_group_name = aws_autoscaling_group.movebase-autoscaling-group.name adjustment_type = “ChangeInCapacity” scaling_adjustment = “-1” cooldown = “300” policy_type = “SimpleScaling” }

resource “aws_cloudwatch_metric_alarm” “movebase-cloudwatch-metric-alarm-cpu-scaledown” { alarm_name = “movebase-cloudwatch-metric-alarm-cpu-scaledown” alarm_description = “movebase-cloudwatch-metric-alarm-cpu-scaledown” comparison_operator = “LessThanOrEqualToThreshold” evaluation_periods = “2” metric_name = “CPUUtilization” namespace = “AWS/EC2” period = “120” statistic = “Average” threshold = “5”

dimensions = { “AutoScalingGroupName” = aws_autoscaling_group.movebase-autoscaling-group.name }

actions_enabled = true alarm_actions = [aws_autoscaling_policy.movebase-autoscaling-policy-cpu-scaledown.arn] }

notification

sns.tf

https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/sns_topic

resource “aws_sns_topic” “movebase-sns-topic” { name = “movebase-sns-topic” }

https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/sns_topic_subscription

resource “aws_sns_topic_subscription” “user_updates_sqs_target” { topic_arn = aws_sns_topic.movebase-sns-topic.arn protocol = “email” endpoint = var.NOTIFICATION_EMAIL }

resource “aws_autoscaling_notification” “example-notify” { group_names = [aws_autoscaling_group.movebase-autoscaling-group.name] topic_arn = aws_sns_topic.movebase-sns-topic.arn notifications = [ “autoscaling:EC2_INSTANCE_LAUNCH”, “autoscaling:EC2_INSTANCE_TERMINATE”, “autoscaling:EC2_INSTANCE_LAUNCH_ERROR” ] }


on ubuntu you can simulate the load

sudo apt install stress stress –cpu 2 –timeout 300

ELB elastic load balancer distributes incomming traffic, scales when you receive
more trafic, it healthcheck all instances (and stop sending traffic to them)
It also used as SSL terminator and manage ssl certificate).
It can be spread over multiple availability zones.
Classic load balancer routes on network level: port 80 to port 8080
ALB routes on application level: /api to different instances
https://github.com/wardviaene/terraform-course/tree/master/demo-16

elb.tf

https://docs.aws.amazon.com/elasticloadbalancing/latest/application/introduction.html#application-load-balancer-components

Each target group routes requests to one or more registered targets, such as

EC2 instances, using the protocol and port number that you specify in

listener. You can register a target with multiple target groups. You can

configure health checks on a per target group basis. Health checks are

performed on all targets registered to a target group that is specified in a

listener rule for your load balancer.

old https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/elb classic

new https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/lb which can be application, network, gateway

todo: tutorial https://medium.com/cognitoiq/terraform-and-aws-application-load-balancers-62a6f8592bcf

todo: long tutorial https://hiveit.co.uk/techshop/terraform-aws-vpc-example/

resource “aws_lb” “movebase-lb” { name = “movebase-lb” security_groups = [aws_security_group.movebase-allow-ssh-and-all-egress.id, aws_security_group.movebase-allow-80.id] subnets = [aws_subnet.movebase-subnet-public-1.id, aws_subnet.movebase-subnet-public-2.id] tags = { Name = “movebase-lb” } }

https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/lb_listener

https://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-listeners.html

resource “aws_lb_listener” “movebase-lb-listener-80” { load_balancer_arn = aws_lb.movebase-lb.arn port = “80” protocol = “HTTP” # fpr ALB: HTTP or HTTPS for NLB: TCP, TLS, UDP and TCP_UDP

default_action { type = “forward” # forward, redirect, fixed-response, authenticate-cognito and authenticate-oidc target_group_arn = aws_lb_target_group.movebase-lb-target-group.arn } }

https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/lb_target_group

resource “aws_lb_target_group” “movebase-lb-target-group” { name = “movebase-lb-target-group” port = 80 protocol = “HTTP” vpc_id = aws_vpc.movebase-vpc.id tags = { Name = “movebase-lb-target-group” } # https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/lb_target_group#health_check health_check { healthy_threshold = 2 unhealthy_threshold = 2 timeout = 3 interval = 30 } }

to connect to autoscaling, we define a link in autoscalling.tf

“aws_lb_target_group_attachment” is used to connect with specific instance

autoscalling.tf

we could also use inline load_balancers inside “aws_autoscaling_group”

https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/autoscaling_attachment

resource “aws_autoscaling_attachment” “movebase-autoscaling-group-attachment” { autoscaling_group_name = aws_autoscaling_group.movebase-autoscaling-group.name alb_target_group_arn = aws_lb_target_group.movebase-lb-target-group.arn }

ECS ec2 container services - cluster for docker containers. You need to start
autoscalling group with custom AMI (which contains ECS agent)

ecs.tf

cluster

resource “aws_ecs_cluster” “example-cluster” { name = “example-cluster” }

resource “aws_launch_configuration” “ecs-example-launchconfig” { name_prefix = “ecs-launchconfig” image_id = var.ECS_AMIS[var.AWS_REGION] instance_type = var.ECS_INSTANCE_TYPE key_name = aws_key_pair.mykeypair.key_name iam_instance_profile = aws_iam_instance_profile.ecs-ec2-role.id security_groups = [aws_security_group.ecs-securitygroup.id] user_data = “#!/bin/bash\necho ‘ECS_CLUSTER=example-cluster’ > /etc/ecs/ecs.config\nstart ecs” lifecycle { create_before_destroy = true } }

resource “aws_autoscaling_group” “ecs-example-autoscaling” { name = “ecs-example-autoscaling” vpc_zone_identifier = [aws_subnet.main-public-1.id, aws_subnet.main-public-2.id] launch_configuration = aws_launch_configuration.ecs-example-launchconfig.name min_size = 1 max_size = 1 tag { key = “Name” value = “ecs-ec2-container” propagate_at_launch = true } } ```

TODO https://medium.com/@ajays871/rails-6-deployment-using-terraform-docker-and-aws-codepipeline-a5fb15ede5eb https://nts.strzibny.name/hybrid-docker-compose-rails/

Swift Xcode Ios

Sun, 06 Feb 2022 00:00:00 +0100

Swift

https://docs.swift.org/swift-book/GuidedTour/GuidedTour.html

let myConst = 42
var myVariable = 1
let implicitDobule = 70.0
let explicitDouble: Double = 70

// string interpolation using \()
var myStr = "My name is \(name)"
// indent is removed if it is the same as ending quotation marks
var myMultilineStr = """
I say "My name is \(name)"
"""

Arrays and dictionaries

var myArray = ["a", "b"]
var myDictionary = [
  "name": "Duke",
]
// to define empty arrays you need to declare type
let emptyArray: [String] = []
let emptyDictionary: [String: Float] = [:]
}

myArray.append("first")

Control flow for loops for in, while, repeat while

let scores = [1, 2]
var result = 0
for score in scores {
  if score > 1 {
    result += 2
  } else {
    result += 1
  }
}

// range of indexes
for i in 0..<4 { }
for i in 0...3 { }

for (_, name) in myDictionary {}

while n < 100 { n *= 2 }

repeat {
  m *= 2
} while m < 100

if statement requires boolean expression or using let with optional string

var optionalName: String? = "a"
if let name = optionalName {
}
optionalName = nil

Handle optional values with default value using ?? operator

let greeting = "Hi \(name ?? "guest")'

If class is optional than you can use ? before calling a method or property, optionalSquare?.radius returns an optional value.

Switch using case

let vegetable = "red pepper"
switch vegetable {
case "celery":
    print("Add some raisins and make ants on a log.")
case "cucumber", "watercress":
    print("That would make a good tea sandwich.")
case let x where x.hasSuffix("pepper"):
    print("Is it a spicy \(x)?")
default:
    print("Everything tastes good in soup.")
}

Functions and Closures Arguments are parameter name and type, You can use custom argument label before parameter name or _ to use no argument label (otherwise you need to call a function with parameter name like greet(person: "John", day: "Wed") if there are more than one parameter)

func greet(_ person: String, on day: String) -> String {
  return "Hello \(person) today is \(day)"
}
print(greet("John", on: "Wed"))

Return value can be a tuple

func cal(scores: [Int]) -> (min: Int, max:  Int) {
  var min = scores[0]
  var max = scores[0]
  return (min, max)
}

You can nest functions. Functions are first class type ie it can be return value from function.

func makeInc() -> ((Int) -> Int) {
  func add(number: Int) -> Int {
    return 1 + number
  }
  return add
}
var inc = makeInc()
print(inc(3))

Functions can take another function as one of its arguments

func hasAnyMatches(_ list: [Int], condition: (Int) -> Bool) -> Bool {
  for item in list {
    if condition(item) {
      return true
    }
  }
  return false
}

func lessThanTen(number: Int) -> Bool {
  return number < 10
}

var numbers = [30, 2, 12]
print(hasAnyMatches(numbers, condition: lessThanTen))

Functions are actually a special case of closures, blocks of code that can be called later. Closure without a name is surrounded with braces, use in to separate arguments and return type from the body

var numbers = [30, 2, 12]
print(numbers.map({ (number: Int) -> Int in
  return 3 * number
}))

When closure type is known (in callback for a delegate) you can omit return type. Single line can omit return. You can also omit parameters and use $0 $1. You can omit parentheses if closure if the only argument.

var numbers = [30, 1, 12]
print(numbers.map({ number in 3 * number}))
print(numbers.map { 3 * $0})
var sorted = numbers.sorted { $0 > $1 }
print(sorted)

Classes uses same let for constants, var for instance property, except that it’s in the context of a class. Use init() for initializers (deinit() for deinitializer for cleanup). If there is a parameter with same name, you can use self.name (otherwise, it is not required when assigning instance property)

class NamedShape {
  var numberOfSides: Int = 0
  var name: String

  init(_ name: String) {
    self.name = name
  }

  func simpleDescription() -> String {
    return "The \(name) shape has \(numberOfSides) sides."
  }
}
var s = NamedShape("My")
s.numberOfSides = 2
print(s.simpleDescription())

Subclasses can override methods. You need to manually call super.init().

class Circle: NamedShape {
  var radius: Int = 0

  init(radius: Int, name: String) {
    super.init(name)
    self.radius = radius
  }
  override func simpleDescription() -> String {
    return "The \(name) circle has \(radius) radius."
  }
}

In addition to simple instance properties, you can have a getter and a setter (it uses newValue implicit name for setter). If you need to call a method when changing the property, you can use willSet and didSet

class MyClass {
  var length: Int
  init(newLength length: Int) {
    length = newLength
  }

  var t: Int {
    get {
      return length
    }
    set {
      length = newValue / 3
    }
  }
}

Enumerations enum can have methods. It starts from zero unless explicitly specifying value. Access raw values using .rawValue property. Use init?(rawValue:) initializer to make an instance of an enumeration from a raw value.

enum Rank: Int {
    case ace = 1
    case two, three

    func simpleDescription() -> String {
        switch self {
        case .ace:
            return "ACE"
        default:
            return String(self.rawValue)
        }
    }
}
let ace = Rank.ace
// or let ace: Rank = .ace
print(ace)
print(ace.rawValue)
print(ace.simpleDescription())

You can use values associated with the case, which are determined when you make an instance, so they can be different for each instance of enumeration case (like stored properties of the enumeration case instance)

enum ServerResponse {
    case result(String, String)
    case failure(String)
}

let success = ServerResponse.result("6:00 am", "8:09 pm")
let failure = ServerResponse.failure("Out of cheese.")

switch success {
case let .result(sunrise, sunset):
    print("Sunrise is at \(sunrise) and sunset is at \(sunset).")
case let .failure(message):
    print("Failure...  \(message)")
}
// Prints "Sunrise is at 6:00 am and sunset is at 8:09 pm."

Structires struct are similar to class just they are always copied, but classes are passed by reference

Protocols can be declared with protocol. use mutating to mark a method that modifies the structure.

protocol ExampleProtocol {
  var simpleDescription: String { get }
  mutating func adjust()
}

class SimpleClass: ExampleProtocol {
  var simpleDescription: String = "A very simple class"
  func adjust() {
    simpleDescription += " now adjusted"
  }
}

Use extension to add functionality to an existing type.

extension Int: ExampleProtocol {
    var simpleDescription: String {
        return "The number \(self)"
    }
    mutating func adjust() {
        self += 42
    }
}
print(7.simpleDescription)
// Prints "The number 7"

Extension is also used to write seed sample data

struct Card {
  var title: String
}
extension Card {
  static let sampleData: [Card] =
  [
    Card(title: "First"),
    Card(title: "Second"),
  ]
}

Error Handling is using any type that adopts Error protocol Use throw to raise an error and throws to mark a function that can throw an error. Code that called a function (with try prefix) handles the error with: do catch, catch is similar to switch Error case ... automatic name is error.

enum PrinterError: Error {
  case outOfPaper
  case onFire
}
func send(job: Int, printerName: String) throws -> String {
  if printerName == "Never has paper" {
    throw PrinterError.outOfPaper
  }
  return "Job \(job) sent"
}

do {
  let result = try send(job: 42, printerName: "Never has paper")
  print(result)
} catch PrinterError.onFire {
  print("Call the fireman")
} catch let printerError as PrinterError {
  print("Printer error: \(printerError)")
} catch {
  print(error)
}

Another way to handle errors is to use try? to convert the result to an optional.

let result = try? send(job: 42, printerName: "Never has paper")

Use defer to write a block of code that’s executed after all other code in the function, just before function returns, it is executed regardless of whether the function throws an error. Please use this cleanup code after setup block

var fridgeIsOpen = false
let fridgeContent = ["milk", "eggs"]
func fridgeContains(_ food: String) -> Bool {
  fridgeIsOpen = true
  defer {
    fridgeIsOpen = false
  }
  let result = fridgeContent.contains(food)
  return result
}
print(fridgeContains("banana"))
print(fridgeIsOpen)

Generic function is created using <Name> which is populated when it is called

func makeArray<Item>(_ item: Item, numberOfTimes: Int) -> [Item] {
  var result: [Item] = []
  for _ in 0..<numberOfTimes {
    result.append(item)
  }
  return result
}
print(makeArray("asd", numberOfTimes: 3))
print(makeArray(1, numberOfTimes: 0))

You can make generic forms of functions, methods, classes, enumeration and structures

// Reimplement the Swift standard library's optional type
enum OptionalValue<Wrapped> {
  case none
  case some(Wrapped)
}
var possibleInteger: OptionalValue<Int> = .none
possibleInteger = .some(100)

Use where right before the body to specify a list of requirements, for example require type to implement a protocol, require a class to have superclass

func anyCommonElements<T: Sequence, U: Sequence>(_ lhs: T, _ rhs: U) -> Bool
    where T.Element: Equatable, T.Element == U.Element
{
    for lhsItem in lhs {
        for rhsItem in rhs {
            if lhsItem == rhsItem {
                return true
            }
        }
    }
    return false
}
anyCommonElements([1, 2, 3], [3])

Ubuntu

Use official vim support

git clone git@github.com:apple/swift.git --depth 1
mkdir ~/.vim/pack/bundle/start -p
cp vim ~/.vim/pack/bundle/start/swift -r

Install swift on Ubuntu from https://www.swift.org/download/ extract to Programs and add Path

echo "PATH=~/Programs/swift-5.5.3-RELEASE-ubuntu20.04/usr/bin:$PATH" >> ~/.bashrc
. ~/.bashrc

Build

touch Package.swift
mkdir Sources
echo print("Hello, world") >> Sources/main.swift
swift build
# .build/debug/Hello

iOS in XCode

https://developer.apple.com/tutorials/app-dev-training

right_click -> Refactor -> Rename
cmd + click -> Embed in VStack
cmd + right_click -> Find
navigate Show next tab, show previous tab with cmd+shift+{} (with default key bindings cmd+{}) I need shift because of karabiner so I remaped Show next/previous tab to cmd+[] so now it works cmd+{} (also use other key kombination for conflicts like Shift left/right and Align left/right edges)
enable vim in Editor -> Vim Mode . You can visually select and cmd+c to copy to clipboard and paste in another program (yank paste works only inside xcode) Add to project .gitignore
```
# .gitignore
*.xcodeproj/
```

When there is an error

Select a scheme that builds a target which contains the current file, or add this file to a target that is built by the current scheme.

than you should close Xcode and remove clean the build folder

rm -rf ~/Library/Developer/Xcode/DerivedData/*

Elements:

view ``` import SwiftUI

struct CardView: View { let card: Card var body: some View { } } struct CardView_Previews: PreviewProvider { static var card = Card.sampleData[0] static var previews: some View { CardView(card: card) .background(card.theme.mainColor) .previewLayout(.fixed(width: 400, height: 60)) } }

* stacks

VStack { Text(“a”) Spacer() HStack { Label(“Info”) Spacer() Label(“More Info”) } } .padding() .foregroundColor(scrum.theme.accentColor)

* List https://developer.apple.com/documentation/swiftui/list

* Label pick icons on https://developer.apple.com/sf-symbols/

Label(“300”, systemImage: “hourglass.bottomhalf.fill”)

struct TrailingIconLabelStyle: LabelStyle { func makeBody(configuration: Configuration) -> some View { HStack { configuration.title configuration.icon } } }

extension LabelStyle where Self == TrailingIconLabelStyle { static var trailingIcon: Self { Self() } }

use like this

* accesibility

Image(systemName: “person”) .accessibilityLabel(“Person”)

# Errors

For

Showing Recent Messages Signing for “Scrumdinger” requires a development team. Select a development team in the Signing & Capabilities editor. ``` You need to select Team by navigating to project (left icon on left window) and find second tab on right window Signing & Capabilities and choose the team (for example Personal Team) and choose unique Bundle Indentifier and you should see: Signging Ceritficate Apple Development email (ASD123)

Tips

Open emulator by navigating to in menu bar Xcode -> Open Developer Tool -> Simulator

icons https://developer.apple.com/sf-symbols/ or online https://github.com/cyanzhong/sf-symbols-online

Terraform Fundamentals

Thu, 30 Dec 2021 00:00:00 +0100

Terraform provides Configuration Management on an infrastructure level, not on the level of software on your machines.

Tutorials

Tutorial excellent https://cloudcasts.io/course/terraform Udemy TODO: https://www.udemy.com/course/learn-devops-infrastructure-automation-with-terraform/ https://github.com/wardviaene/terraform-course

Install

Download binary https://www.terraform.io/downloads

brew tap hashicorp/tap
brew install hashicorp/tap/terraform
terraform -install-autocomplete

Usage

Commands

# download provider plugins
terraform init
# Terraform has created a lock file .terraform.lock.hcl to record the provider
# selections it made above. Include this file in your version control repository
git init .
cat >> .gitignore << 'HERE_DOC'
.terraform/
terraform.tfvars
terraform.tfstate
terraform.tfstate.backup
HERE_DOC

# check the changes live
terraform plan
# you can save to a binary file and apply them
terraform plan -out changes.terraform && terraform apply changes.terraform
# see plan changes
terraform plan -out /tmp/tfplan && terraform show -json /tmp/tfplan | jq -r ".resource_changes[0].change.before.data , .resource_changes[0].change.after.data"

# push the changes
terraform apply
terraform apply -auto-approve # accept yes
# I suggest to save the state in git
terraform apply -auto-approve && git add .

# correct the format
terraform fmt
# validate syntax
terraform validate

# inspect current state from terraform.tfstate
terraform show

# to show all resources from current state
terraform state list
# to rename resource
terraform state mv aws_instance.example aws_instance.production

# create visual representation of a configuration or execution plan
terraform graph

# find resource ID and import to the state as ADDRESS. Only for importing the
# state still need to write resource definitions since next apply will remove it
# todo: https://learn.hashicorp.com/tutorials/terraform/state-import
terraform import ADDRESS ID
terraform import aws_instance.example i-0dba323asd123

# show defined outputs
terraform output
terraform output resource-name

# refresh remote state
terraform refresh

# configure remote state storage
terraform remote

# to remove
# this will clear the state file but you can restore using git or
# terraform.tfstate.backup
terraform destroy
# destroy specific resource
terraform destroy --target aws_instance.demo_vm_1

# manually mark resource as tainted, it will be destructed and recreated at the
# next apply
terraform taint
terraform untaint

main.tf for terraform block (for main setting and providers) https://registry.terraform.io/ and for resources

# main.tf
terraform {
  required_providers {
    # https://www.terraform.io/language/providers/requirements
    docker = {
      source  = "kreuzwerker/docker"
      version = "~> 2.13.0"
    }
  }
}

# resource.tf
# provider block use local name of the provider
provider "docker" {}

# resource block has two strings before block: resource type and resource name
# prefix for resource type match the provider name. resource id is type.name
resource "docker_image" "nginx" {
  name         = "nginx:latest"
  keep_locally = false
}

# access the container on http://localhost:8000/
resource "docker_container" "nginx" {
  image = docker_image.nginx.latest
  name = "tutorial"
  ports {
    internal = 80
    external = 8000
  }
}

Variable_block

https://learn.hashicorp.com/tutorials/terraform/variables

# variables.tf
# if variable does not have value or default, it will be asked
variable "AWS_ACCESS_KEY" {}

variable "mystring" {
  type = string
  default = "hello"
}

variable "mynumber" {
  type = number
  default = 1.42
}

variable "mybool" {
  type = bool
  default = true
}

# list is array
variable "mylist" {
  description = "A list of zones"
  type = list(string)
  default = [ "abc", "qwe" ]
}

variable "mymap" {
  type = map(string)
  default = {
    mykey = "my value"
    # also colon is possible
    mykey: "my value"
  }
}
variable "AMIS" {
  type = map
  default = {
    # find ami on https://cloud-images.ubuntu.com/locator/ec2/ search example us-east-1 hvm
    # https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/finding-an-ami.html#finding-quick-start-ami
    us-east-1 = "ami-0b0ea68c435eb488d"
  }
}

variable "myset" {
  type = set
  default = [1, 2]
}

variable "myobject" {
  type = object({name=string, age=number})
  default = {
    name = "Joe"
    age = 42
  }
}

variable "mytuple" {
  type = type([number, string, bool])
  default = [0, "string", false]
}

Use

# tuple is like a list with a different type
[0, "string", false]

# identifiers can contain letters, digits, underscore, hyphens, but first char
# must not be a digit. If key in a map is not valid identifier, it has to be
# quoted

# you can override variable as attribute:
terraform apply -var "myvar=NewName" -var "RDS_PASSWORD=$PASSWORD"_

# you can see variables inside `terraform console` but you can not define
# variable inside console. Also you can not see outputs, but you can use
# directly their values
aws_s3_bucket.my-bucket.arn

# you can play with functions:
tomap({"k"="v", "k2"="v2"}) # returns { "k"="v", "k2"="v2" }
tolist("a", "b") # returns array ["a", "b"]

# string
var.myvar
"${var.myvar}" # interpolation inside string
# string manipulation
coalesce(string1, string2) # returns first non empty value
format("server-%03d", count.index + 1)  returns server-001 server-002
join(delim, mylist), join(",", var.AMIS) # ami-1,ami-2
replace("aaab", "a", "c") # "cccb"
split(",", "a,b,c") # ["a", "b", "c"]
substring("abcd", offset, length)

# map
var.mymap["mykey"]
var.mymap.mykey
keys(mymap) # ["mykey"]
values(mymap) # ["my value"]
lookup(var.mymap, "mykey", "default")
merge(map1, map2) # merge two hashes

# list
var.mylist[0] # same as element(var.mylist, 0)
var.mylist[*].arn # splat expression `*` instead of index returns list or arns
index(mylist, elem) # find index of element in a mylist
slice(var.mylist, 0, 2)

# access to one property in the list of maps
[ { a = "a" }, { a = "c" }][*].a
# [ "a", "c" ]

timestamp()
uuid()

You can also reference values of resources aws_s3_bucket.name

Secrets are usually stored in terraform.tfvars (autoloaded is terraform.tfvars and any file *.auto.tfvars, other name can be loaded like -var-file="testing.tfvars") which should be git ignored since it contains all keys in format NAME = "value"

AWS_ACCESS_KEY = "AKIA..."
AWS_SECRET_KEY = "6JX..."
AWS_REGION = "us-east-1"

You can use env to define variables when you export with prefix TF_VAR_ env variable export TF_VAR_DB_PASSWORD=asd1234. So use it instead of using terraform.tfvars

To output variable which was marked as sensitive you can

t output DB_PASSWORD explicitly show that value
grep --after-context=10 outputs terraform.tfstate grep state

decode plan that is saved in tmp folder

t plan -target=vault_generic_secret.foobar -out=/tmp/tfplan
t show -json /tmp/tfplan  | jq -r ".resource_changes[0].change.before.data , .resource_changes[0].change.after.data"

mark as non sensitive

  output "mysecret" {
    value = nonsensitive(var.mysecret)
  }

Math ${2+3*4}

Count object has .index attribute and can be used for iterations

resource "aws_iam_user" "example" {
  count = length(var.mylist)
  # name = "neo.${count.index}"
  name = var.mylist[count.index]
}

and resulting resource is actually array of resources so we have to use []

output "first_user_arn" {
  value = aws_iam_user.example[0].arn
}
output "all_users_arn" {
  value = aws_iam_user.example[*].arn
}

Count can not be used to loop over inline block. When you remove from the list, other elements will be moved by one position ie lot of resources changes instead of one single resource deletion This is not the case with for_each https://www.terraform.io/language/meta-arguments/for_each Usually create variable map with numbers and you can use each.key and each.value

variable "public_subnet_numbers" {
  type = map(number)
  description = "Map of AZ to a number that should be used for public subnet, used in for_each"
  default = {
    us-east-1a = 1
    us-east-1b = 2
  }
}
resource "aws_subnet" "public" {
  for_each = var.private_subnet_numbers
  cidr_block = each.value
}

output "keys" {
  value = keys(aws_subnet.public)
}
# or in console: keys(aws_subnet.public)
# [ "us-east-1a", "us-east-1b"...
output "all_arns" {
  value = values(aws_subnet.public)[*].arn
}

output of for_each on resource is a map, keys are keys in for_each, values are resources. Removing one element from map will result in removing one resource (no shifting down other resources).

Conditionals can be defined in 3 ways, using count paramentar, string directives and for_each

# ternary syntax
count = "${var.env == "prod" ? 2 : 1 }"

To conditionally make resource use count and star * for output

variable "enable_eip" {
  description = "If set to true, enable eip"
  type        = bool
}

resource "aws_eip" "ec2_eip" {
  # ternary syntax
  count = var.enable_eip ? 1 : 0
}

output "ec2_eip_public_ip" {
  value = aws_eip.ec2_eip.*.public_ip
  # or
  value = var.enable_eip ? aws_eip.ec2_eip[0].public_ip : null
}

If else can be implemented in a similar way (count = var.enable_eip ? 0 : 1) When you need to pick the value of one that has been defined you can use one(concat())

output "neo_cloudwatch_policy_arn" {
  value = one(concat(
    aws_iam_user_policy_attachment.full_access[*].policy_arn,
    aws_iam_user_policy_attachment.read_only[*].policy_arn
  ))
}

String directives can have two forms: for directive (loop) and if directive (conditional)

# %{ for <ITEM> in <COLLECTION> }<BODY>%{ endfor }
output "for_directive" {
  value = "%{ for name in var.mylist }${name}, %{ endfor }"
}
# for_directive = "neo, trinity, morpheus, "

# for directive with index
# %{ for <INDEX>, <ITEM> in <COLLECTION> }<BODY>%{ endfor }
output "for_directive_index" {
  value = "%{ for i, name in var.names }(${i}) ${name}, %{ endfor }"
}
# for_directive_index = "(0) neo, (1) trinity, (2) morpheus, "

if string directive for condition to remove last , and put .

output "for_directive_index_if_else_strip" {
  value = <<EOF
%{~ for i, name in var.names ~}
${name}%{ if i < length(var.names) - 1 }, %{ else }.%{ endif }
%{~ endfor ~}
EOF
}
# for_directive_index_if_else_strip = "neo, trinity, morpheus."

For expression (for loops). Return type depends if we wrap with [] or {} (requires => sumbol). https://www.terraform.io/language/expressions/for

[for s in ["a", 1]: upper(s)]
{for k,v in { "a"=1 } : upper(k) => v}

# you can split map based on if condition:
variable "users" {
  type = map(object({
    is_admin = bool
  }))
}
locals {
  admin_users = {
    for name, user in var.users : name => user
    if user.is_admin
  }
}

# to group results, ie merge values to array, add three dots ...
locals {
  users_by_role = {
    for name, user in var.users : user.role => name...
  }
}

Nested block does no have equal sign and we can repeat them

  nested_block {
  }
  nested_block {
  }

For nested block we can use for_each loop using dynamic and content keywords and .key and .value attributes of the nested_block variable. Iteration with for_each uses set or map (list can be converted withfor_each = toset(var.mylist))

  dynamic "nested_block" {
    for_each = [22, 443]
    content {
      from_port   = nested_block.value
      to_port     = nested_block.value
      protocol    = "tcp"
    }
  }

To create multiple subnets you can use https://www.terraform.io/language/functions/cidrsubnets

  cidr_block = cidrsubnet(aws_vpc.vpc.cidr_block, 4, each.value)

# X.X.xxxx0000.0000
cirdsubnets("10.1.0.0/16",4)
# ["10.1.0.0/20"]
cirdsubnets("10.1.0.0/16",4, 4)
# ["10.1.0.0/20", "10.1.16.0/20"]

Data

Use data from provider, like search for ami https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/instance

# ami.tf
data "aws_ami" "ami" {
  # https://cloud-images.ubuntu.com/locator/ec2/
  # https://awscli.amazonaws.com/v2/documentation/api/latest/reference/ec2/describe-images.html
  # in case of error in creating an instance, try to find ami-123 on web
  # https://us-east-1.console.aws.amazon.com/ec2/v2/home?region=us-east-1#Images:visibility=public-images
  # and create instance from web console to see minimum requirements
  # or with cli aws ec2 describe-images --image-ids ami-0a24ce26f4e187f9a

  most_recent = true
  filter {
    name = "name"
    values = ["ubuntu/images/hvm-ssd/ubuntu-jammy-22.04-amd64-server-*"]
  }

  owners = ["099720109477"] # Canonical official

  # https://stackoverflow.com/questions/28168420/choose-a-free-tier-amazon-machine-image-ami-using-ec2-command-line-tools
  # aws ec2 describe-images --owner amazon --filter "Name=description,Values=*Ubuntu*" "Name=owner-alias,Values=amazon" "Name=architecture,Values=x86_64" "Name=image-type,Values=machine" "Name=root-device-name,Values=/dev/sda1" "Name=root-device-type,Values=ebs" "Name=virtualization-type,Values=hvm"
  # filter {
  #   name = "root-device-type"
  #   values = ["ebs"]
  # }
  # filter {
  #   name = "description"
  #   values = ["*Ubuntu*"]
  # }
  # filter {
  #   name = "owner-alias"
  #   values = ["amazon"]
  # }
  # filter {
  #   name = "architecture"
  #   values = ["x86_64"]
  # }
}

output "ami_id" {
  value = data.aws_ami.ami.id
}

Random

# https://registry.terraform.io/providers/hashicorp/random/latest/docs/resources/shuffle
resource "random_shuffle" "subnet_id" {
  input = var.subnet_ids
  result_count = 1
}

# usage
  subnet_id = random_shuffle.subnet_id.result[0]

Project structure

staging/
production/
modules/

to differentiate between accounts you can use different profiles aws configure Each folder has it’s own terraform.tfvars which is autoloaded.

You can run from root using script and -chdir

# run.sh
#!/usr/bin/env bash
 
TF_ENV=$1
 
DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
 
# Always run from the location of this script
cd $DIR
 
if [ $# -gt 0 ]; then
    if [ "$2" == "init" ]; then
        terraform -chdir=./$TF_ENV init -backend-config=../backend-$TF_ENV.tf
    else
        terraform -chdir=./$TF_ENV $2
    fi
fi
 
# Head back to original location to avoid surprises
cd -

Also you can create separate folders in each env so for example you can update ec2 instances without need to take care rds resources (for example if rds is updated on aws you have to update in terraform, but ec2 team does not need to think about rds at all). To reference resources from other folder you can use data and filter, for example to find vpc from ec2 folder

# variables.tf
data "aws_vpc" "vpc" {
  tags = {
    Name        = "cloudcasts-${var.infra_env}-vpc"
    Project     = "cloudcasts.io"
    Environment = var.infra_env
    ManagedBy   = "terraform"
  }
}

data "aws_subnet_ids" "public_subnets" {
  vpc_id = data.aws_vpc.vpc.id

  tags = {
    Name        = "cloudcasts-${var.infra_env}-vpc"
    Project     = "cloudcasts.io"
    Environment = var.infra_env
    ManagedBy   = "terraform"
    Role        = "public"
  }
}

Workspaces

You can organize different environment you can use Workspaces https://www.terraform.io/language/state/workspaces

When state is local file, it will create new terraform.tfstate.d/dev/ folder On S3 it prepends state file with workspace name. When you change the folder, it will change the workspace

terraform workspace list
terraform workspace new dev
terraform workspace show

use like variable

# variables.tf
locals {
  env = terraform.workspace
}

# main.tf
  env = local.env

SSH key pair

For aws we use ssh keypairs for which we need resource aws_key_pair

# variables.tf
variable "PATH_TO_PUBLIC_KEY" {
  default = "my_key.pub"
}
variable "PATH_TO_PRIVATE_KEY" {
  default = "my_key"
}

# key_pairs.tf
# https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/key_pair
# key is generated with: ssh-keygen -f my_key
resource "aws_key_pair" "mykeypair" {
  # existing keys can be imported with: terraform import aws_key_pair.deployer deployer-key
  # https://console.aws.amazon.com/ec2/v2/home?region=us-east-1#KeyPairs:
  # mykeypair will be destroyed when we run terraform destroy
  # Find IP address from aws console or using output
  # ssh -i my_key ubuntu@3.84.117.126
  # ssh -i my_key ubuntu@$(cat terraform.tfstate | jq -r '.resources[].instances[].attributes.public_ip | select( . != null )')
  # ssh -i my_key ubuntu@$(aws ec2 describe-instances --query "Reservations[*].Instances[*].PublicIpAddress" --output=text)
  key_name = "mykeypair"
  public_key = file(var.PATH_TO_PUBLIC_KEY)
}

# resource.tf
resource "aws_instance" "example" {
  ami           = lookup(var.AMIS, var.AWS_REGION)
  instance_type = "t2.micro"
  key_name = aws_key_pair.mykeypair.key_name

For error

│ Error: error importing EC2 Key Pair (my_key): InvalidParameterValue: Value for parameter PublicKeyMaterial is invalid. Length exceeds maximum of 2048.

Provision software

Use file uploads with file provisioner and remote-exec to run the script

provisioner "file" {
  source = "app.conf"
  destination = "/etc/myapp.conf"
  connection {
    type = ssh
    user = var.instance_username
    password = var.instance_password
  }
}

  provisioner "file" {
    source = "script.sh"
    destination = "/tmp/script.sh"
  }
  provisioner "remote-exec" {
    inline = [
      "chmod +x /tmp/script.sh",
      "sudo /tmp/script.sh"
    ]
  }
  # another way to output info is using local-exec provisioner (it is performed
  # only first time resource is created)
  provisioner "local-exec" {
    command = "echo ${aws_instance.example.private_ip} >> private_ips.txt"
  }
  connection {
    user = var.INSTANCE_USERNAME
    private_key = file(var.PATH_TO_PRIVATE_KEY)
    host = self.public_ip
  }
}
output "ip" {
  description = "Public IP address for EC2 instance"
  value = aws_instance.example.public_ip
}
output "private_ip" {
  value = aws_instance.example.private_ip
}

Add to var

variable "INSTANCE_USERNAME" {
  default = "ubuntu"
}

# script.sh
#!/bin/bash
apt-get update
apt-get -y install nginx

State

terraform.tfstate is where it keeps track of remote state. there is also terraform.tfstate.backup for previous state. You can keep terraform.tfstate in git repo so you can see state changes. For example when you remove the instance from aws console, terraform apply will make a changes to meet the correct remote state. Also if you remove tfstate file , it will try to create all new (duplicated) resources since it lots ids. For single user repo you can add both terraform.tfstate and .terraform.lock.hcl to the repo. Lock is important so we use same versions of the providers and modules.

# Find all resource names
cat terraform.tfstate | jq '.resources[].name'
# find public_ip
cat terraform.tfstate | jq '.resources[].instances[].attributes.public_ip | select( . != null )'

But for multiuser project, another person can change the state so you loose the sync since you do not use same lock. You can save state remote using a backend functionality in terraform https://www.terraform.io/language/settings/backends/remote

Credentials are different then those secrets for provision.

# backend.tf
terraform {
  backend "s3" {
    bucket = "trk-tfstates"
    key = "myapp/terraform.tfstate"
    profile = "2022trk"
    region = "eu-central-1"
  }
}

and run terraform init to set up the backend. Inside bucket properties you should enable “Versions” to see old states. To can enable state locking, you should create a dynamodb table with LockID partition key and if you name the table tfstate-lock you can use like

    dynamodb_table = "tfstate-lock"

https://www.terraform.io/language/settings/backends/s3#dynamodb-state-locking

Packer

https://learn.hashicorp.com/packer you can create a custom image todo: https://learn.hashicorp.com/collections/terraform/provision

Other providers

https://registry.terraform.io/browse/providers Any company that opens API can be an provider: Datadog (monitoring), Github, mailgun, DNSSimple

Providers are similar.

Template provider templatefile

For creating customized configuration files, template based on variables from resource attributes (for example public ip address). Use case is cloud init config (user-data on AWS). https://www.terraform.io/language/functions/templatefile

# modules/ec2/user_data_httpd_server.tftpl
#!/bin/bash
sudo apt update -y
sudo apt install -y apache2
echo "Hello World from hostname=$(hostname -f) subnet_id=${subnet_id}" > /var/www/html/index.html

use templatefile(file, map) function

resource "aws_instance" "web" {
  user_data = templatefile("${path.module}/user_data_httpd_server.tftpl", {
    subnet_id = random_shuffle.subnet_id.result[0]
  })
}

Locals and tags

Since we can not use variables inside other variables, we can use local which is defined with pluralized version locals. We will use it to set the name and other important information that can be defined as tags

locals {
  common_tags = {
    Name = "${var.environment}-web-server"
    Environment = var.environment
    ManagedBy = "terraform"
    SourceUrl = "https://github.com/duleorlovic/tf-aws-s3-static-website-bucket"
    TfstateUrl = "@air:terraform_modules/tf-aws-s3-static-website-bucket/examples/create_static_site/terraform.tfstate"
  }

resource "aws_vpc" "vpc" {
  tags = merge(local.common_tags, {
    Name = "${var.env}-vpc"
  })
}

if you want to provide ability to override any tag you can use merge ., override

variable "override_tags" {
  type = map(string)
  description = "Override or add new tags"
  default = {}
}

resource "aws_vpc" "vpc" {
  tags = merge(merge(local.common_tags, {
    Name = "${var.env}-vpc"
  }),
    var.override_tags
  )
}

Lifecycle

https://www.terraform.io/language/meta-arguments/lifecycle You can ignore certain changes (for example tags) and create before destroy

 lifecycle {
    ignore_changes = [
      # Ignore changes to tags, e.g. because a management agent
      # updates these based on some ruleset managed elsewhere.
      tags,
    ]
    create_before_destroy = true
    prevent_destroy = true # for example not to release public ip
  }

To prevent downtime you can create new resources, apply, remove unused resources, and apply again. Many resources has immutable parameters so terraform will remove them and create another (instead of updating) so try to use create_before_destroy strategy.

Modules

Done https://learn.hashicorp.com/collections/terraform/modules Todo https://www.terraform.io/language/modules/develop/composition TODO: https://blog.gruntwork.io/how-to-create-reusable-infrastructure-with-terraform-modules-25526d65f73d

You can organize files inside folders (locally) or remote on github. To use it you need to define source. You can define version and other meta arguments like count, depends_on

module "module-example" {
  source = "github.com/duleorlovic/terraform-module-example"
  # locally
  source = "./module-example"

  # override or add additional arguments
  region = "us-east-1"
}

Example module has at least three files: main, outputs.tf (variables that other modules can use) and variables.tf (input variables defined inside module):

# module-example/variables.tf
variable "region" {} # the input parameter
variable "ip-range" {}

# module-example/cluster.tf
resource "aws_instance" "instance-1" {
}

# module-example/outputs.tf
output "aws-cluster" {
  value = aws_instance.instance-1.public_ip
}

To use output of module you can reference module.module-name.output-name

output "some-output" {
  value = module.module-example.aws-cluster
}

You have access to path.cwd, path.module and path.root. To download you need to run get or init

terraform get
ls -l .terraform/modules

Move

https://learn.hashicorp.com/tutorials/terraform/move-config I think you can access module resources directly (no need to output)

moved {
  from = aws_instance.example
  to = module.ec2_instance.aws_instance.example
}

I tried to move a list or resources (created with for_each), but no success, it recreated them (maybe to try from = aws_instance.example.us-east-1a or from = values(aws_instance.example)[0]

Terraform Cloud

quick start

terraform login
git clone https://github.com/hashicorp/tfc-getting-started.git
cd tfc-getting-started/
scripts/setup.sh

todo: https://learn.hashicorp.com/collections/terraform/cloud-get-started

VIM

https://github.com/hashicorp/terraform-ls/blob/main/docs/USAGE.md#cocnvim Add json to :CocConfig and install language server

brew install hashicorp/tap/terraform-ls

https://github.com/evilmartians/terraforming-rails/tree/master/tools/lint_env

Kubernetes

Sat, 20 Nov 2021 00:00:00 +0100

Learn

Online learn deploy https://kubernetes.io/docs/tutorials/kubernetes-basics/ (it uses https://www.katacoda.com/ ) Another online playground https://labs.play-with-k8s.com/

Install Kubernetes locally

Kind, k3d, minikube or microk8s

Kind

https://kind.sigs.k8s.io/

K3d

https://k3d.io/

Example 3 nodes

k3d cluster create gaia --servers 1 --agents 2 --port 80:80@loadbalancer --port 443:443@loadbalancer --api-port 6443 --k3s-arg '--no-deploy=traefik@server:*'

Minikube

Install minikube

curl -LO https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64
sudo install minikube-linux-amd64 /usr/local/bin/minikube

minicube itself is running inside docker

minikube start
minikube ip

# to stop
docker ps
minikube stop

Microk8s

For ubuntu you can use https://microk8s.io/docs

sudo snap install microk8s --classic --channel=1.21
sudo usermod -a -G microk8s $USER
newgrp microk8s

microk8s status --wait-ready
# microk8s is running

# to stop
microk8s stop

You can use alias

alias k=microk8s.kubectl

or you can copy config

microk8s config > ~/.kube/config

It is running as /snap/microk8s/2694/kubelite proccess. To stop run

microk8s stop

Kubectl

Install kubectl https://kubernetes.io/docs/tasks/tools/

curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
sudo install -o root -g root -m 0755 kubectl /usr/local/bin/kubectl

Check if kubectl can access

export KUBECONFIG=~/.kube/kubernetes-rails-example-kubeconfig.yaml
kubectl version

# this will create Deployment, ReplicaSet and Pod
kubectl run my-nginx --image nginx

kubectl create deployment httpenv --image=bretfisher/httpenv
kubectl delete pod/httpenv-6fdc8554fb-f568c
kubectl scale deployment/httpenv --replicas 5
# create ClusterIP
kubectl expose deployment/httpenv --port 8888

kubectl get nodes -o wide # find node ip address
kubectl get pods -o wide # pods are running on nodes, always replaced
kubectl get pods -w # watch
kubectl get pod my-pod -o jsonpath="{.spec.containers[0].ports[0].containerPort}"
kubectl get services
kubectl get svc hello
kubectl get events
kubectl get deployments
kubectl get all

kubectl describe service my-load-balancer
kubectl describe pods

kubectl config view

kubectl logs -l app=rails-app -f # print logs from rails-app pods
kubectl logs my-pod -p # log for specific pod of previous crashed CrashLoopBackOff instance

kubectl apply -f config/kube/terminal.yml

# live edit kubernetes
kubectl edit service/my-service
kubectl edit replicaset/app-nginx-deployment-56845f96cc

kubectl exec terminal -- date # run command in first container inside pod
kubectl exec terminal -it -- bash # run bash inside first container
kubectl exec terminal -c ruby-container -it bash # run ssh inside specific con
kubectl exec terminal -it -- bundle exec rails console

# to trigger refresh deploy you can simply remove
kubectl delete pods -l app=rails-app

kubectl create -f config/kube/migrate.yml
kubectl wait --for=condition=complete --timeout=600s job/migrate
kubectl delete job migrate

export POD_NAME=$(kubectl get pods --namespace default -l "app.kubernetes.io/name=application-1,app.kubernetes.io/instance=chart-1" -o jsonpath="{.items[0].metadata.name}")
export CONTAINER_PORT=$(kubectl get pod --namespace default $POD_NAME -o jsonpath="{.spec.containers[0].ports[0].containerPort}")
echo "Visit http://127.0.0.1:8080 to use your application"
# $POD_NAME is chart-1-application-1-6bcd5f68bd-kjmqr $CONTAINER_PORT is 80
kubectl --namespace default port-forward $POD_NAME 8080:$CONTAINER_PORT

To list all kinds that we can create

kubectl api-resources
NAME        SHORTNAMES   APIVERSION NAMESPACED   KIND
bindings                 v1         true         Binding
componentstatuses cs     v1         false        ComponentStatus
nodes       no           v1         false        Node
deployments deploy       apps/v1    true         Deployment

To list all versions that are supported

kubectl api-versions

Find docs for specific API object

kubectl explain services
kubectl explain services --recursive
kubectl explain services.spec.type
# note that this is a documentation of the client (not from the server, so maybe
server does not support that version)

Full references is on https://kubernetes.io/docs/reference/

To see what generated configuration is used from cli arguments

kubectl create deployment sample --image nginx --dry-run -o yaml > deployment.yml
apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    app: sample
  name: sample
spec:
  replicas: 1
  selector:
    matchLabels:
      app: sample
      ...

kubectl expose deployment/test --port 80 --dry-run -o yaml

You can see changes on server that differs from yaml

kubectl diff -f app.yml

Declarative is more what needs to be created, but impperative is more how. Declerative is using apply command and we do not care how it will be performed to the desired state.

Docs

Learn Kubernetes with videos https://www.youtube.com/hashtag/kubernetesessentialsfromgooglecloud and documentation for example Specs for pod https://kubernetes.io/docs/reference/kubernetes-api/workload-resources/pod-v1/#PodSpec

Control plane is a set of containers that manage the cluster, includes: API server, scheduler, controller manager, etcd, CoreDNS On nodes we have: kubelet (agent running on nodes) and kube-proxy.

Yaml

Four root keys are: apiVersion, kind, metadata and spec. Inside metadata you can use labels (for example: app: api, env: prod) and for large objects use annotations

Pods

Pod is one or more containers running together on one Node. Pod is basic unit of deployment. Containers are always in pods. Controller is used for creating and updating pods, many types of controlles: Deployment, ReplicaSet, DaemonSet, Job

Pod can be in Pending Running Succeded Failed Unknown phase https://kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle/#pod-phase Container state (old has Pending state - insufficient resource)

Waiting - Pod can’t run (there are enough resource but maybe image can not be downloaded yet)
Running - you can debug using exec or logs
Terminated - either ran to completion or failed for some reason

Use probe to check container status https://kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle/#container-probes

Example

# pod.yml
apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  containers:
  - name: nginx
    image: nginx:1.17.3
    ports:
    - containerPort: 80

but that does not create replica set so better is to create Deployment

# config/kube/deployment.yml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: kubernetes-rails-example-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: rails-app
  template:
    metadata:
      labels:
        app: rails-app
    spec:
      containers:
      - name: rails-app
        image: duleorlovic/kubernetes-rails-example:latest
        ports:
        - containerPort: 3000

Services

Services route traffic to pods matching app: MyApp and redirects traffic from 80 to 9376 only on internal cluster ip address.

apiVersion: v1
kind: Service
metadata:
  name: my-service
spec:
  type: ClusterIP
  selector:
    app: MyApp
  ports:
    - protocol: TCP
      port: 80
      targetPort: 9376

https://www.youtube.com/watch?v=uGm_A9qRCsk https://kubernetes.io/docs/concepts/services-networking/service/ https://medium.com/google-cloud/kubernetes-nodeport-vs-loadbalancer-vs-ingress-when-should-i-use-what-922f010849e0 Service types: ClusterIP (default) is reachable only inside cluster. NodePort is opening a specific (high) port on a specific machine LoadBalancer is used for using cloud-provided load balancer to route traffic between services pods but since you pay for every exposed service it is cheaper to use Ingress which can run on one port and route based on domain or path ExternalName adds CNAME DNS record to CoreDNS

# create ClusterIP
kubectl expose deployment/httpenv --port 8888
# create terminal
kubectl run tmp-shell --rm -it --image bretfisher/netshoot -- bash
curl httpenv:8888
# find ip from kubectl get services
curl 10.152.183.129:8888

# create NodePort
kubectl expose deployment/httpenv --port 8888 --name httpenv-np --type NodePort
kubectl get services # this returns ports 8888:31471
# from host
curl localhost:31471
curl 10.152.183.129:8888
curl <hostname>.<namespace>.svc.cluster.local

3rd party proxy: Traefik, HAProxy, Nginx

Namespaces

Namespaces is used to filter group of object in cluster https://www.youtube.com/watch?v=plB3kyZLHe8 Debug services and dns with exec https://www.youtube.com/watch?v=CSKRy7Ldqis

Namespace Authentication and cluster is defined inside ~/.kube/config You can see all clusters with

kubectl config get-contexts
CURRENT   NAME       CLUSTER            AUTHINFO   NAMESPACE
*         microk8s   microk8s-cluster   admin

ConfigMap

kubectl create configmap nginx-frontend.conf --from-file nginx/frontend.conf

You can create using yml

# config/kube/env.yml
apiVersion: v1
kind: ConfigMap
metadata:
  name: env
data:
  RAILS_ENV: production
  RAILS_LOG_TO_STDOUT: enabled
  RAILS_SERVE_STATIC_FILES: enabled
  DATABASE_URL: postgresql://example.com/mydb
  REDIS_URL: redis://redis.default.svc.cluster.local:6379/

and use in your container

envFrom:
- configMapRef:
    name: env

You can create from text

kubectl create secret generic rails-secrets --from-literal=rails_master_key='example'

and use in container

env:
  - name: RAILS_MASTER_KEY
    valueFrom:
      secretKeyRef:
        name: rails-secrets
        key: rails_master_key

Secrets

kubectl create secret generic tls-certs --from-file tls/

StatefulSets

Use db-as-a-service whenever you can. Volumes tied to lifecycle of a Pod, all containers in a single Pod can share them. PersistentVolumes created at cluster level, outlives a Pod, multiple Pods can share them.

Templating YAML

https://kustomize.io/ is template free, using overrides

docker app and compose-on-kubernetes https://kompose.io/

Helm

It is similar to liquid shopify template language.

sudo snap install helm --classic

microk8s.enable helm3

Example

heml install chart-1 .
heml list
helm uninstall chart-1

You can see generated template or apply them

helm template .
helm template . | kubectl apply -f -

https://helm.sh/docs/chart_template_guide/getting_started/ Template

It is using sprig library https://helm.sh/docs/howto/charts_tips_and_tricks/

{ {/* and */}} comment
{ {- define "labels" -}} and use with { { include "application-1" . | nindent 4 }}
{ {- if eq .Values.container1.enabled true -}} or short { {- if .Values.container1.enabled -}} flow control https://helm.sh/docs/chart_template_guide/control_structures/

Chart repository https://helm.sh/docs/topics/chart_repository/ you can run your own chartmuseum https://chartmuseum.com/docs/#helm-chart For grafana we use

helm repo add grafana https://grafana.github.io/helm-charts
helm search repo grafana
helm install my-grafana grafana/grafana

# if you want to customize
helm pull grafana/grafana
tar -xf grafana-6.20.3.tgz

# remove chart
helm uninstall my-grafana

Dashboard

kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v2.4.0/aio/deploy/recommended.yaml
kubectl proxy
Starting to serve on 127.0.0.1:8001

Context

https://blog.mikesir87.io/2019/08/using-ssh-connections-in-docker-contexts/ You can access docker using ssh (no need to expose docker port, only ssh with keys authentication is enough)

# create
docker context create ssh-box --docker "host=ssh://user@my-box"


# Set the context for a single command
docker --context=ssh-box ps

# OR set the context globally
docker context use ssh-box
docker ps

# OR use the DOCKER_CONTEXT env var
DOCKER_CONTEXT=ssh-box docker ps

Security

https://docs.docker.com/engine/security/ https://github.com/BretFisher/ama/issues/17

namespace: access to own cpu, ram… (by default they can use all, so you need to limit) and view only its own filesystem (not from other containers)
use non root user USER node and COPY --chown=node

Ruby

https://kubernetes.io/docs/reference/using-api/client-libraries/#community-maintained-client-libraries

Rails

Deploy rails to kubernetes https://kubernetes-rails.com/

# Dockerfile
FROM ruby:2.6.3

# update yarn repo
RUN curl https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add -
RUN echo "deb https://dl.yarnpkg.com/debian/ stable main" > /etc/apt/sources.list.d/yarn.list
# update node
RUN curl -sL https://deb.nodesource.com/setup_14.x | bash -
RUN apt-get update && apt-get install -y nodejs yarn postgresql-client

RUN mkdir /app
WORKDIR /app

COPY Gemfile Gemfile.lock ./
RUN gem install bundler
RUN bundle install
COPY . ./

RUN bundle exec rake assets:precompile

EXPOSE 3000
CMD ["bundle", "exec", "rails", "server", "-b", "0.0.0.0"]

Create, test and push image to duleorlovic/kubernetes-rails-example:latest

docker build -t duleorlovic/kubernetes-rails-example .
docker run -p 3000:3000 duleorlovic/kubernetes-rails-example
docker push duleorlovic/kubernetes-rails-example

Enable kubernetes to download docker from private repo

kubectl create secret docker-registry my-docker-secret --docker-server=DOCKER_REGISTRY_SERVER --docker-username=DOCKER_USER --docker-password=DOCKER_PASSWORD --docker-email=DOCKER_EMAIL
kubectl edit serviceaccounts default

TODO http://blog.jedrychowski.org/2018/rails-kubernetes-basic-deployment/ rancher https://www.youtube.com/watch?v=LK6KbAlQRIg kubernetes https://www.youtube.com/watch?v=X48VuDVv0do

https://evilmartians.com/chronicles/kubing-rails-stressless-kubernetes-deployments-with-kuby

Digital ocean

Digital ocean install

sudo snap install doctl
doctl auth init
doctl kubernetes cluster kubeconfig save 901f6f80-2728-4ac7-bc5e-77365d839e39

Check if we can access

export KUBECONFIG=~/.kube/kubernetes-rails-example-kubeconfig.yaml
kubectl version
kubectl get nodes

Setup Kubernetes using Vagrant Virtuarbox https://medium.com/swlh/setup-own-kubernetes-cluster-via-virtualbox-99a82605bfcc https://github.com/mbaykara/k8s-cluster

Vim

Using coc-yaml plugin for coc https://github.com/neoclide/coc-yaml so we have code completion and documentation similar to VSCode https://octetz.com/docs/2020/2020-01-06-vim-k8s-yaml-support/ https://www.youtube.com/watch?v=eSAzGx34gUE

Install coc https://github.com/neoclide/coc.nvim/wiki/Install-coc.nvim using native package manager vim8

mkdir -p ~/.vim/pack/coc/start
cd ~/.vim/pack/coc/start
git clone --branch release https://github.com/neoclide/coc.nvim.git --depth=1

inside vim run

:CocInfo
:CocInstall coc-yaml

It is installing https://github.com/redhat-developer/vscode-yaml so run :CocConfig to edit ~/.vim/coc-settings.json

{
  "yaml.schemas": {
      "kubernetes": ["/*.yaml"]
  }
}

Copy paste keys https://github.com/neoclide/coc.nvim#example-vim-configuration

Control-space or tab is used to code complete. Use <c-p> and <c-n> to go to next or prev item, or just type letters.

Sidecar pattern

Book Designed Distributed Systems” by Brendan Burns https://azure.microsoft.com/en-us/resources/designing-distributed-systems/

Nginx

Fri, 29 Oct 2021 00:00:00 +0200

Nginx using docker

Run docker image, default page, on port 80

docker container run -p 80:80 nginx

Add a container name and mount your fileds to default nginx path /usr/share/nginx/html and remove when you stop it

docker container run --name nginx --rm -v $(pwd):/usr/share/nginx/html -p 80:80 nginx

Test main config

docker run --name my-custom-nginx --rm -v $(pwd)/n.conf:/etc/nginx/nginx.conf:ro -p 80:80 nginx

Test default config /etc/nginx/conf.d/default.conf

docker run --name my-custom-nginx --rm -v $(pwd)/d.conf:/etc/nginx/conf.d/default.conf:ro -p 80:80 nginx
docker run --name my-custom-nginx --rm -v $(pwd)/d.conf:/etc/nginx/conf.d/default.conf:ro -v $(pwd):/data/www -p 80:80 nginx

Run bash command inside container

docker container run -it nginx bash

or cat default config

docker container run nginx cat /etc/nginx/conf.d/default.conf

NGINX config

http://nginx.org/en/docs/beginners_guide.html

Simple directives ends with ; semicolon. Block directives ends with a block {} braces and they define context. Directives outside of any context are considered to be in the main context, like http and events directives (location is inside server inside http context).

http {
  server {
    listen 80 default_server;
    server_name my.domain.com;
    location / {
      root /data/www;
    }
  }
}

server blocks are distinguished by ports on which they listen and by server names.

location parametar should match URI in the request header. Server uses the longest location path prefix.

root is used as prefix for URI. It could be inside location or server.

listen is a port on which to listen, use default_server param to set as default is no other servers is matched by the server_name http://nginx.org/en/docs/http/request_processing.html

http://nginx.org/en/docs/http/server_names.html server_name is used to pick different servers (if nothing matches, default_server or first server will be used). You can prevent access without host using a empty server_name put it as first or default_server. Enable health-check path since it is usually accessed by IP address.

# Test with a command
# docker run --name my-custom-nginx --rm -v $(pwd)/d.conf:/etc/nginx/conf.d/default.conf:ro -p 80:80 nginx
#
# http://nginx.org/en/docs/http/request_processing.html#how_to_prevent_undefined_server_names
server {
  listen 80 default_server;
  server_name "";
  location / {
    return 444;
  }
  # https://serverfault.com/questions/196929/how-to-reply-with-200-from-nginx-without-serving-a-file
  location /health-check {
    return 200 'gangnam style!';
    add_header Content-Type text/plain;
  }
}
server {
  listen 80;
  server_name dule;
  location / {
    return 200 'dule';
    add_header Content-Type text/plain;
  }
}

ngx http rewrite module

You can use set $upstream 127.0.0.1:3000; to define variable and use it in proxy_pass http://$upstream; http://nginx.org/en/docs/http/ngx_http_rewrite_module.html#set

Config generateor https://www.digitalocean.com/community/tools/nginx

Elektronsko Potpisivanje Apr Mup Citac Kartica Eporezi Na Virtual Box Windows Mac Linux

Thu, 07 Oct 2021 00:00:00 +0200

Evo kako mozete da koristite elektronsko potpisivanje na bilo kom racunaru (linux ubuntu mac windows). Od hardvera vam je dovoljno samo da imate slobodnog hard diska i memorije (nisam siguran za minimum, ja sam imao 100GB slobodno na eksternom hard disku i 16GB RAM memorije) i usb biometrijski citac kartica koje se lepo prepoznaje u virtual boxu, meni radi Yankee YCR 101, Gamalto CT31 (meni ne radi Trust primo smart card reader).

Skinuti windows koji cemo pokrenuti unutar virtual masine uz pomoc VirtualBox:

VirtualBox za vas sistem https://www.virtualbox.org/wiki/Downloads
Windows 10 VirtualBox image https://developer.microsoft.com/en-us/windows/downloads/virtual-machines/

Otpakovati WinDev2108Eval.VirtualBox.zip i pomocu VirtualBox programa otvoriti dobijeni fajl WinDev2108Eval.ova. Ako VirtualBox prijavljuje gresku

amd-v is disabled in the bios (or by the host os) (verr_svm_disabled).

onda treba da omogucite AMD SVM u biosu

Kada se pokrene virtualna masina attachovati usb smart card reader na nju (to treba da radite svaki put kada se pokrene masine). Ako ne vidite usb devices onda treba da dodate sebe u vobxusers grupu sudo usermod -aG vboxusers dule i restart (logout ne pomaze).

Mozete provetiti da li se uredjaj prepoznao na windowsu tako sto kliknete desni klik na Windows ikonu pa na Device Manager i tamo bi trebalo da stoji Smart card readers i Smart cards (ukoliko ste ubacili licnu kartu u citac, obicno cip stoji na gore, a slika prema dole).

Sa sajta ustanove od koje ste uzeli certifikat treba da skinete midleware. Ja sam vadio sertifikat u MUP-u tako da sam instalirao TrustEdge 64 bitni

TrustEdgeID_x64 sa http://ca.mup.gov.rs/ca/ca_cyr/start/kes/ klik na + ИНСТАЛАЦИЈА СОФТВЕРА ЗА ЛИЧНЕ КАРТЕ

Mozete instalirati i Celik aplikaciju za citanje licne karte. Sve ostale alate vec imate u WinDev virtualnoj masini.

I to je to sto treba da instalirate. Posle pratite uputstva za elektronsko potpisivanje.

ePorezi treba da ispise Citac i kartica prepoznati pa kliknete na Podnesi prijavu i unesete vas pin kod za licnu kartu, Otvorice vam se browser na adresi https://eporezi.purs.gov.rs/

Potpis na APR

Za APR potpis na https://webreg.apr.gov.rs/ereg (prijava moze preko consent mobilne aplikacije, ali za potpis se trazi cartifikat sa kartice ili licne karte) mup ЛАНЦИ СЕРТИФИКАТА И ЛИСТЕ ОПОЗВАНИХ СЕРТИФИКАТА nexu apr Uputstvo_MUP.pdf

Proverite verziju

pokrenite novu 1.35 verziju sa https://dl.apr.gov.rs https://dl.apr.gov.rs/NexU-APR.exe
korisiti edge umesto chrome na windowsu
restart windowsa pomaze

Certifikat poste

Cartifikati poste rade lepo koristeci njihov USB i tokenmanager aplikaciju

https://aplikacije3.apr.gov.rs/ElektronskoPotpisivanje https://webreg.apr.gov.rs/ereg

duleorlovic - web developer

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