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:*'

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

minikube start
minikube ip

# to stop
docker ps
minikube stop

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

alias k=microk8s.kubectl

microk8s config > ~/.kube/config

microk8s stop

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

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

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

kubectl api-versions

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)

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

kubectl diff -f app.yml

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

# 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

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

# 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

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

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

# 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/

envFrom:
- configMapRef:
    name: env

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

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

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

sudo snap install helm --classic

microk8s.enable helm3

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

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

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

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

# 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

# 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"]

docker build -t duleorlovic/kubernetes-rails-example .
docker run -p 3000:3000 duleorlovic/kubernetes-rails-example
docker push duleorlovic/kubernetes-rails-example

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

sudo snap install doctl
doctl auth init
doctl kubernetes cluster kubeconfig save 901f6f80-2728-4ac7-bc5e-77365d839e39

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

mkdir -p ~/.vim/pack/coc/start
cd ~/.vim/pack/coc/start
git clone --branch release https://github.com/neoclide/coc.nvim.git --depth=1

:CocInfo
:CocInstall coc-yaml

{
  "yaml.schemas": {
      "kubernetes": ["/*.yaml"]
  }
}