.Kubernetes-Kubectl-Commands

Summary: Useful Kubectl commands for deploying & managing apps in a Kubernetes cluster (Minikube as example)

2-Deploying-And-Exposing-Loadbalancer.sh

#!/bin/bash

## Deploy a simple dummy echo service
kubectl create deployment hello-minikube1 --image=k8s.gcr.io/echoserver:1.3

## Expose the service via a NodePort and map the internal port 8080 to an external port, which is generated when the command is executed
kubectl expose deployment hello-minikube1 --type=NodePort --port 8080

## Minikube does not support LoadBalancers, so this example ends here

2-Deploying-And-Exposing-NodePort.sh

#!/bin/bash

## Deploy a simple dummy echo service
kubectl create deployment hello-minikube1 --image=k8s.gcr.io/echoserver:1.3

## Expose the service via a NodePort and map the internal port 8080 to an external port, which is generated when the command is executed
kubectl expose deployment hello-minikube1 --type=NodePort --port 8080

## Get the generated external port and echo it
export NODE_PORT=$(kubectl get services hello-minikube1 -o go-template='{{(index .spec.ports 0).nodePort}}')
echo NODE_PORT=$NODE_PORT

## Curl the exposed port
curl $(minikube ip):$NODE_PORT

3-Labelling-Container-Pods

#!/bin/bash

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

4-Deleting-Pods.sh

#!/bin/bash

## Delete the pod
kubectl delete service -l run=hello-minikube1

## Confirm that the pod is deleted
curl $(minikube ip):$NODE_PORT

5-Scaling-A-Container-Pod.sh

#!/bin/bash

## Scale up the number of instances to 4 replicasets within the Pod
kubectl scale deployments hello-minikube1 --replicas=4

## Check that the ReplicaSets were scaled up to 4
kubectl get deployments
kubectl get pods -o wide

## Note: A NodePort is able to load balance between the replicasets automatically

## Scale down the number of instances to 2 replicasets within the Pod
kubectl scale deployments hello-minikube1 --replicas=2

## Check that the ReplicaSets were scaled down to 2
kubectl get deployments
kubectl get pods -o wide

6-Perform-Rolling-Update.sh

#!/bin/bash

## Update image from version echoserver:1.3 to echoserver:1.4
kubectl set image deployments hello-minikube1 hello-minikube1=k8s.gcr.io/echoserver:1.4

## Check Rolling Update Status
kubectl rollout status deployments hello-minikube1

## Performing a Rollback/Undo for a Rolling Update
kubectl rollout undo deployments/kubernetes-bootcamp