Kubernetes

# 安装 kubectl
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

# 安装 kind
go install sigs.k8s.io/kind@v0.14.0

常用命令

Common command

kubectl version
kubectl get nodes
kubectl get pods
kubectl describe pods

Deploy app

# deploy app
kubectl create deployment kubernetes-bootcamp --image=gcr.io/google-samples/kubernetes-bootcamp:v1
kubectl get deployments

# IN ANOTHER TERMINAL: The kubectl command can create a proxy that will forward communications into the cluster-wide, private network. After starting it will not output a response.
kubectl proxy

# curl api from public
curl http://localhost:8001/version

# export Pod name
export POD_NAME=$(kubectl get pods -o go-template --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}')
echo Name of the Pod: $POD_NAME
# curl pod info
http://localhost:8001/api/v1/namespaces/default/pods/$POD_NAME/

# log by POD_NAME
kubectl logs $POD_NAME

# use the exec command and use the name of the Pod as a parameter
kubectl exec $POD_NAME env

# start a bash session in the Pod’s container
kubectl exec -ti $POD_NAME bash

Exposing App

# Create a new service
kubectl get pods
kubectl get services
kubectl expose deployment/kubernetes-bootcamp --type="NodePort" --port 8080
kubectl get services
kubectl describe services/kubernetes-bootcamp
export NODE_PORT=$(kubectl get services/kubernetes-bootcamp -o go-template='{{(index .spec.ports 0).nodePort}}')
curl $(minikube ip):$NODE_PORT

# Using labels
kubectl describe deployment
kubectl get pods -l run=kubernetes-bootcamp
kubectl get services -l run=kubernetes-bootcamp
export POD_NAME=$(kubectl get pods -o go-template --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}')
kubectl label pod $POD_NAME app=v1
kubectl describe pods $POD_NAME

# Deleting a service
kubectl delete service -l run=kubernetes-bootcamp
kubectl get services
curl $(minikube ip):$NODE_PORT
kubectl exec -ti $POD_NAME curl localhost:8080

Scaling App

# Scaling a deployment
kubectl get deployments
kubectl scale deployments/kubernetes-bootcamp --replicas=4
kubectl get deployments
kubectl get pods -o wide
kubectl describe deployments/kubernetes-bootcamp

# Load Balancing
kubectl describe services/kubernetes-bootcamp
export NODE_PORT=$(kubectl get services/kubernetes-bootcamp -o go-template='{{(index .spec.ports 0).nodePort}}')
curl $(minikube ip):$NODE_PORT

# Scale Down
kubectl scale deployments/kubernetes-bootcamp --replicas=2

Updating App

# Update the version of the app
kubectl get deployments
kubectl get pods
kubectl describe pods
kubectl set image deployments/kubernetes-bootcamp kubernetes-bootcamp=jocatalin/kubernetes-bootcamp:v2
kubectl get pods

# Verify an update
kubectl describe services/kubernetes-bootcamp
export NODE_PORT=$(kubectl get services/kubernetes-bootcamp -o go-template='{{(index .spec.ports 0).nodePort}}')
curl $(minikube ip):$NODE_PORT
kubectl rollout status deployments/kubernetes-bootcamp
kubectl describe pods

# Rollback an update
kubectl set image deployments/kubernetes-bootcamp kubernetes-bootcamp=gcr.io/google-samples/kubernetes-bootcamp:v10
kubectl get deployments
kubectl get pods
kubectl describe pods
kubectl rollout undo deployments/kubernetes-bootcamp
kubectl get pods
kubectl describe pods