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kubernetes

tip

What can Kubernetes do for you? With modern web services, users expect applications to be available 24/7, and developers expect to deploy new versions of those applications several times a day. Containerization helps package software to serve these goals, enabling applications to be released and updated without downtime. Kubernetes helps you make sure those containerized applications run where and when you want, and helps them find the resources and tools they need to work. Kubernetes is a production-ready, open source platform designed with Google's accumulated experience in container orchestration, combined with best-of-breed ideas from the community.

Learn kubernetes basiscs​

https://kubernetes.io/docs/tutorials/kubernetes-basics/

Create kubernetes cluser​


gcloud container clusters create [CLUSTER-NAME]

gcloud container clusters get-credentials [CLUSTER-NAME]

Create kubernetes deployment from a image​

kubectl create deployment hello-server --image=gcr.io/google-samples/hello-app:1.0

Create kubernetes service​

kubectl expose deployment hello-server --type=LoadBalancer --port 8080

In this command: --port specifies the port that the container exposes. type="LoadBalancer" creates a Compute Engine load balancer for your container.

Get Services​

kubectl get service

Creating POD​

apiVersion: v1
kind: Pod
metadata:
  name: monolith
  labels:
    app: monolith
spec:
  containers:
    - name: monolith
      image: kelseyhightower/monolith:1.0.0
      args:
        - "-http=0.0.0.0:80"
        - "-health=0.0.0.0:81"
        - "-secret=secret"
      ports:
        - name: http
          containerPort: 80
        - name: health
          containerPort: 81
      resources:
        limits:
          cpu: 0.2
          memory: "10Mi"
kubectl create -f pods/monolith.yaml
kubectl get pods
kubectl describe pods monolith

Port forwarding​

kubectl port-forward monolith 10080:80

Get logs​

kubectl logs monolith
## Stream logs
kubectl logs -f monolith

Interactive shell inside the pod​

kubectl exec monolith --stdin --tty -c monolith /bin/sh

### Check the external connectivity
ping -c 3 google.com

Check deployments​

kubectl explain deployment
kubectl explain deployment --recursive
kubectl explain deployment.metadata.name

Scale the deployment​

kubectl scale deployment hello --replicas=5
## Verify the scale
kubectl get pods | grep hello- | wc -l

Trigger rolling update​

kubectl edit deployment hello

kubectl get replicaset

kubectl rollout history deployment/hello

kubectl rollout pause deployment/hello

kubectl rollout status deployment/hello

kubectl get pods -o jsonpath --template='{range .items[*]}{.metadata.name}{"\t"}{"\t"}{.spec.containers[0].image}{"\n"}{end}'

kubectl rollout resume deployment/hello

kubectl rollout undo deployment/hello

Delete Cluster​

gcloud container clusters delete [CLUSTER-NAME]