Cheatsheet: Kubernetes Commands

Updated Apr 07, 2022 ·

Pods and Parameters

Pods	Description
kubectl completion --help	Search for "enabling completion"
source <(kubectl completion bash)	Enable completion for kubectl
kubectl api-resources	List shortnames for resources
kubectl get pods	Get information about running pods in the current namespace
kubectl describe pod <pod>	Describe a specific pod
kubectl expose pod <pod> --port=444 --name=frontend	Expose the port of a pod (creates a new service)
kubectl port-forward <pod> 8080	Port forward the exposed pod port to your local machine
kubectl attach <podname> -i	Attach to the pod
kubectl exec <pod> -- command	Execute a command on the pod
kubectl exec -it pod-name bash	SSH into the pod
kubectl label pods <pod> mylabel=awesome	Add a label to a pod
kubectl run -i --tty busybox --image=busybox --restart=Never -- sh	Run a shell in a pod (useful for debugging)

Parameters	Description
--all-namespaces	Display resources in all namespaces
-l LABEL-NAME	Filter by a specific label name
-l LABEL-NAME1,LABEL-NAME2	Filter by multiple label names
--sort-by=metadata.creationTimestamp	Sort pods by age
--output=yaml	Display output in YAML format
--o yaml	Display output in YAML format (can also use JSON)
--wide	Display additional information in the output
--show-labels	Show labels attached to the pods

kubectl create vs. kubectl apply

• kubectl create is used for Imperative Management, where you directly specify what you want to create, replace, or delete in the cluster.

  Example:

  kubectl create deployment my-deployment --image=nginx

• kubectl apply is used for Declarative Management, where it ensures that changes to live objects (like scaling) are preserved even if you apply further changes.

  Example:

  kubectl apply -f my-manifest.yaml

Key difference:

• kubectl create will fail if the resource already exists.
• kubectl apply will update the resource without error.

Deployments

Deployments	Description
kubectl get deployments	Get information on current deployments
kubectl get rs	Get information about the replica sets
kubectl rollout status deployment/helloworld-deployment	Get the deployment status
kubectl set image deployment/helloworld-deployment k8s-demo=k8s-demo	Update deployment with the new version of the k8s-demo image
kubectl edit deployment/helloworld-deployment	Edit the deployment object
kubectl rollout status deployment/helloworld-deployment	Check the status of the rollout
kubectl rollout history deployment/helloworld-deployment	View the rollout history
kubectl rollout undo deployment/helloworld-deployment	Roll back to the previous version
kubectl rollout undo deployment/helloworld-deployment --to-revision=n	Roll back to a specific version