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How to setup k8s autocomplete and other useful information – see official kubectl Cheat Sheet

First of all, export ENV with the path to k8s config:

export KUBECONFIG=~/.kube/your-project-config

Namespace

Get all namespaces

kubectl get ns

Then you can work in particular namespace by adding -n namespace-name to every command or by specyfing current default namespace:

kubectl get pod -n namespace-name
kubectl edit secret/app-secret -n namespace-name

# same result by setting default namespace
kubectl config set-context --current --namespace=namespace-name
kubectl get pod
kubectl edit secret/app-secret

Or you can get resources across all namespaces:

kubectl get pods --all-namespaces
kubectl get services --all-namespaces

Secrets

Get secret

kubectl get secret/some-secret -n namespace-name -o yaml

Edit secret

kubectl edit secret/some-secret -n namespace-name

Sometimes you need to "restart" pod after changing a secret to use new version of secret. First option is to delete a pod. Find a pod(s): kubectl get pod -n some-namespace, delete it kubectl delete pod-name -n some-namespace. Second option:

kubectl -n ... scale deploy DEPLOYNAME --replicas=0
kubectl -n ... scale deploy DEPLOYNAME --replicas=1

Investigate problems

Find needed deploy and pod and describe them

kubectl get pod
kubectl describe pod/PODNAME
kubectl get deploy
kubectl describe deploy/DEPLOYNAME

Get logs

kubectl logs PODNAME
kubectl logs pod/PODNAME
kubectl logs deploy/DEPLOYNAME

Connect to pod container in interactive mode / execute command

kubectl exec -it -n NAMESPACE deploy/DEPLOYNAME bash

Show metrics

kubectl top nodes
kubectl top pod -n NAMESPACE
kubectl top pod POD_NAME --containers

Create (run) job from existing one

kubectl create job --from=cronjob/JOB_NAME -n NAMESPACE manual-backup-`date +%s`

Wait for job completion (helpful for bash scripts)

kubectl wait --for=condition=complete job/YOUR_JOB_NAME --timeout=5m -n NAMESPACE

Get all pods hosted on a particular node

kubectl get pods --all-namespaces -o wide --field-selector spec.nodeName=NODE_NAME

Add basic auth

Create password

htpasswd -c auth USERNAME

Fill password. Then:

kubectl create secret generic basic-auth --from-file=auth -n NAMESPACE

Then find a deploy/statefulset, edit it (kubectl edit deploy/DEPLOYNAME ...) and add to annotations:

nginx.ingress.kubernetes.io/auth-type: basic
nginx.ingress.kubernetes.io/auth-secret: basic-auth
nginx.ingress.kubernetes.io/auth-realm: 'Authentication Required'