kubectl Cheat Sheet

From

https://kubernetes.io/docs/reference/kubectl/cheatsheet/
https://cheat-sheets.nicwortel.nl/kubectl-cheat-sheet.pdf
https://dockerlabs.collabnix.com/kubernetes/cheatsheets/kubectl.html
https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands

Configuration File and Environment Variables

By default configuration is in ~/.kube/config.

Environment variables. Most important environment variable:

KUBECONFIG=$HOME/.kube/dev-config

Global flags

Flag	Description
`-A,--all-namespaces`	Use all the namespaces
`-n,--namespace <namespace>`	The name of the namespace to use
`--help`	Show information about a given command

Context and configuration

kubectl config

Command	Description
`kubectl config get-contexts`	List all contexts
`kubectl config current-context`	Display the current context
`kubectl config use-context <context>`	Switch to another context
`kubectl config delete-context <context>`	Delete the specified context from the kubeconfig

Display resources

Use kubectl get or kubectl describe

Command	Description
`kubectl get <resource>`	List all resources of this type in the current namespace
`kubectl get <resource> -o wide`	List all resources with more details
`kubectl get <resource> -A`	List all resources of this type in all namespaces
`kubectl get <resource> <name>`	List a particular resource
`kubectl get <resource> <name> -o yaml`	Print a particular resource in YAML format
`kubectl get <resource> <name> -l <key1>=<value1>`	List resources where label `<key1>` contains `<value1>`
`kubectl describe <resource>`	Show detailed information about a resource

E.g. to list all pods:

kubectl get pod \
    -o=custom-columns=NODE:.spec.nodeName,NAME:.metadata.name \
    --all-namespaces

or just pods in one namespace:

kubectl get pod --namespace <namespace>

then

kubectl describe pod <podname> --namespace <namespace>

to get logs:

kubectl logs <pod>

Relevant events:

kubectl get events --namespace app-namespace  --sort-by='.metadata.creationTimestamp'

Apply configuration manifests

kubectl apply

Command	Description
`kubectl apply -f <file>`	Apply a manifest from a file
`kubectl apply -f <dir>`	Apply all manifests in a directory
`kubectl apply -k <dir>`	Apply resources from a kustomize directory

Create multiple YAML objects from stdin:

kubectl apply -f - <<EOF
apiVersion: v1
kind: Pod
metadata:
  name: busybox-sleep
spec:
  containers:
  - name: busybox
    image: busybox:1.28
    env:
    - name: SLEEP_DURATION
      value: "1000000"
    args:
    - sleep
    - "${SLEEP_DURATION}"
---
apiVersion: v1
kind: Pod
metadata:
  name: busybox-sleep-less
spec:
  containers:
  - name: busybox
    image: busybox:1.28
    env:
    - name: SLEEP_DURATION
      value: "1000"
    args:
    - sleep
    - "${SLEEP_DURATION}"
EOF

Create resources manually

kubectl run

Command	Description
`kubectl run <name> --image=<image>`	Start a pod
`kubectl create deployment <name> --image=<image>`	Create a deployment
`kubectl expose pod <pod> --port=<port>`	Create a service for an existing pod
`kubectl expose deployment <name> --port=<port>`	Create a service for an existing deployment
`kubectl create ingress <name> --rule=<host/path=svc:port>`	Create an ingress that routes traffic to a service
`kubectl create job <name> --image=<image>`	Create a job
`kubectl create job <name> --from=cronjob/<name>`	Create a job from a cronjob
`kubectl create cronjob <name> --image=<image> --schedule=<schedule>`	Create a cronjob, using a schedule in Cron format
`kubectl create secret generic <name> --from-literal=<key>=<value>`	Create a secret containing `<key>` and `<value>`
`kubectl create secret docker-registry <name> --docker-server=<server> --docker-username=<username> --docker-password=<password>`	Create a secret for a Docker registry

E.g. to get an interactive shell within your cluster:

kubectl run my-shell --rm -i --tty --image ubuntu -- bash

where:

my-shell - the name of the Deployment that is created. Your pod name will be this plus a unique hash or ID at the end.
--rm - when you exit out of your session, this cleans up the Deployment and Pod.
-i/--tty - the combination of these is what allows us to attach to an interactive session.
-- delimits the end of the kubectl run options from the positional arg bash.
bash - overrides the container’s CMD. In this case, we want to launch bash as our container’s command.

Generate YAML configuration manifests

Use kubectl create or kubectl expose.

Command	Description
`kubectl create deployment <name> --image=<image> --dry-run=client -o yaml`	Generate a deployment manifest
`kubectl expose deployment <name> --port=<port> --dry-run=client -o yaml`	Generate a service manifest for a deployment

Edit resources

kubectl-edit, kubectl-set.

Command	Description
`kubectl edit <resource> <name>`	Edit a resource in a text editor
`kubectl set image <resource> <name> <container>=<image>`	Update the image of a container in a pod

Set labels and annotations

Command	Description
`kubectl label <resource> <name> <key>=<value>`	Add a label to a resource
`kubectl annotate <resource> <name> <key>=<value>`	Add an annotation to a resource

Delete resources

kubectl delete

Command	Description
`kubectl delete <resource> <name>`	Delete a particular resource
`kubectl delete <resource> --all`	Delete all resources of a particular type in the current namespace

To delete a pod:

kubectl delete pod busybox-sleep-less

Create/Replace/Delete from a file

kubectl-create, kubectl-delete, kubectl-replace

Command	Description
`kubectl create -f <file>`	Create a resource from a file
`kubectl delete [--force] -f <file>`	Delete a resource from a file
`kubectl replace [--force] -f <file>`	Delete then create a resource from a file

Manage deployments

kubectl rollout

Command	Description
`kubectl rollout status deployment <name>`	Show the status of a deployment rollout
`kubectl rollout history deployment <name>`	View the rollout history of a deployment
`kubectl rollout undo deployment <name>`	Undo a previous rollout deployment
`kubectl rollout restart deployment <name>`	Restart a deployment
`kubectl scale deployment <name> --replicas=<n>`	Scale a deployment to `<n>` replicas
`kubectl autoscale deployment <name> --min=<min> --max=<max>`	Autoscale a deployment between `<min>` and `<max>` replicas

Execute commands

kubectl exec

Command	Description
`kubectl exec <pod> -- <command>`	Execute a command in a running pod
`kubectl exec -it <pod> --container main-app -- sh`	Open a shell in a running pod

View logs

kubectl logs

Command	Description
`kubectl logs <pod> -n <namespace>`	Print the logs for a pod
`kubectl logs -f <pod> -n <namespace>`	Print the logs for a pod and keep streaming

Resource usage

kubectl top Command|Description —-|—— kubectl top node|Show resource (CPU/memory) usage of nodes kubectl top pod|Show resource (CPU/memory) usage of pods

Other commands

Command	Description
`kubectl version`	Show the version of the client and server
`kubectl api-resources`	Print the supported API resources on the server

Switching context with kubectx

Use kubectx to switch the cluster you work with.

To list all contexts:

kubectx

To see the current context:

kubectx -c

To switch to a new context:

kubectx <context_name>

To switch back to previous context:

kubectx -

Switching namespace with kubectx kubens

To switch to a new namespace:

kubens <new_namespace>

To switch back to previous namespace:

kubens -

Notes to Self

Alex Sokolsky's Notes on Computers and Programming