Kubernetes.md

Cluster Information

Print the client and server version information

kubectl version

Print the supported API resources on the server

kubectl api-resources

Print the supported API versions on the server, in the form of "group/version"

kubectl api-versions

Print the cluster information

kubectl cluster-info

Get the list of the nodes in the cluster

kubectl get nodes

Get information of the master node

kubectl get nodes master -o wide

Get detailed information on the master nodes

kubectl describe nodes master

Configuration Information

Display merged kubeconfig settings

kubectl config view

View the current context

kubectl config current-context

Set the context, here kubernetes-admin@kubernetes is the context name

kubectl config use-context kubernetes-admin@kubernetes

Display clusters defined in the kubeconfig

kubectl config get-clusters

Describe one or many contexts

kubectl config get-contexts

Namespaces

Get all namespaces

kubectl get namespaces

Get namespace information in yaml format

kubectl get namespaces -o yaml

Describe the default namespace

kubectl describe namespace default

Create a new namespace

kubectl create namespace my-namespace

Delete the namespace

kubectl delete namespace my-namespace

Pods

Get pods from the current namespace

kubectl get pods

Get pods from all the namespaces

kubectl get pods --all-namespaces

Get pods from the specified namespace

kubectl get pods -namespace=my-namespace

Create a pod

kubectl run my-pod-1 --image=nginx:latest --dry-run

see how the pod would be processed

kubectl run my-pod-1 --image=nginx:latest --dry-run=client

Create a pod in the specified namespace

kubectl run my-pod-2 --image=nginx:latest --namespace=my-namespace

Create a pod with a label to it

kubectl run nginx --image=nginx -l --labels=app=test

Get all pods with label output

kubectl get pods --show-labels

Get pods with exapanded/wide output

kubectl get pods -o wide

List pods in a sorted order

kubectl get pods --sort-by=.metadata.name

Get logs of the pod

kubectl logs my-pod-1

Get pods within the specified namespace with exapanded/wide output

kubectl get pods my-pod-2 --namespace=my-namespace -o wide

Get logs of the pod within the specified namespace

kubectl logs my-pod-2 --namespace=my-namespace

Describe the pod

kubectl describe pod my-pod-1

Describe the pod within the specified namespace

kubectl describe pods my-pod-1 --namespace=my-namespace

Delete the pod from the current namespace

kubectl delete pod my-pod-1

Delete the pod from the specified namespace

kubectl delete pods my-pod-1 --namespace=my-namespace

Deployments

Get a list of deployments from the current namespace

kubectl get deployments

Get a list of deployments from the specified namespace

kubectl get deployments --namespace=my-namespace

Create a deployment

kubectl create deployment my-deployment-1 --image=nginx

Get the specified deployment

kubectl get deployment my-deployment-1

Get the specified deployment with its labels

kubectl get deployment my-deployment-1 --show-labels

Describe the specified deployment

kubectl describe deployments my-deployment-1

Get details of the deployment in yaml format

kubectl get deployment my-deployment-1 -o yaml

Change image in the existing deployment

kubectl set image deployment my-deployment-1 nginx=nginx:1.16.1

View rollout history

kubectl rollout history deployment my-deployment-1

Undo a previous rollout

kubectl rollout undo deployment my-deployment-1

Go back the specific version of the rollout history

kubectl rollout undo deployment my-deployment-1 --to-revision=2

Show the status of the rollout

kubectl rollout status deployment my-deployment-1

Restart a resource

kubectl rollout restart deployment my-deployment-1

Scale deployment to 3

kubectl scale --replicas=3 deployment my-deployment-1

Scale from current count to the desired

kubectl scale --current-replicas=3 --replicas=5 deployment my-deployment-1 This will create an HPA (Horizontal Pod Aotuscaler)

kubectl autoscale deployment my-deployment-1 --min=2 --max=10

Services

First, create a pod with the label app=myapp.

Then:

Create a pod with a label

kubectl run my-pod --image=nginx --labels=app=myapp

Create a service of type NodePort which will use pod's labels for selector but we have to specify the type, so create a definition file first and then create a service

kubectl expose pod my-pod --port=80 --name nginx-service --type=NodePort --dry-run=client -o yaml

Create a Service which will have type type NodePort but this will not have selector as my-app

kubectl create service nodeport nginx --tcp=80:80 --node-port=30080 --dry-run=client -o yaml

Get services from the current context

kubectl get service

Get details of the services

kubectl get service -o wide

Get services with labels on them

kubectl get service --show-labels

Get services from all the namespaces

kubectl get services --all-namespaces

Describe the service to know more about it

kubectl describe service nginx-service

Get a particular service

kubectl get service nginx-service

Delete the service

kubectl delete service nginx-service

Manage Objects from .yaml/.yml files

First, create a definition file for a pod

Create a definition file for pod

kubectl run mypod --image=nginx --dry-run=client -o yaml > my-pod.yml

Create an object

kubectl create -f my-pod.yml

Delete the object

kubectl delete -f my-pod.yml