kubectl Cheat Sheet

kubectl config get-contexts                        # which clusters?
kubectl config current-context
kubectl config use-context staging                 # switch cluster
kubectl config set-context --current --namespace=shop   # default namespace
kubectl get pods -n kube-system                    # one namespace
kubectl get pods -A                                # all namespaces

kubectl get pods                   # pods here
kubectl get pods -o wide           # with node and IP
kubectl get pods -w                # keep watching
kubectl get pods -l app=web        # by label
kubectl get pods --show-labels
kubectl get deploy,svc,ingress     # several kinds at once
kubectl get all                    # the common kinds (not everything)
kubectl get nodes
kubectl api-resources              # every kind, with short names
kubectl explain deployment.spec.strategy   # docs for any field

kubectl describe pod web-7d9f8           # status and EVENTS: start here
kubectl logs web-7d9f8                   # current logs
kubectl logs web-7d9f8 --previous        # logs from before the last crash
kubectl logs -f web-7d9f8 -c sidecar     # follow one container
kubectl logs -l app=web --tail=50        # from every pod with a label
kubectl exec -it web-7d9f8 -- sh         # a shell inside
kubectl debug -it web-7d9f8 --image=busybox --target=app   # a debug container
kubectl debug node/worker-2 -it --image=ubuntu             # a shell on a node
kubectl get events --sort-by=.lastTimestamp
kubectl port-forward pod/web-7d9f8 8080:80
kubectl port-forward svc/web 8080:80

kubectl apply -f app.yaml                 # create or update from a file
kubectl apply -f ./k8s/                   # every file in a folder
kubectl apply --dry-run=server -f app.yaml   # check without changing anything
kubectl diff -f app.yaml                  # what would change?
kubectl delete -f app.yaml
kubectl edit deploy web                   # edit live (and lost on next apply)
kubectl label pod web-7d9f8 tier=front
kubectl annotate deploy web owner=ops

kubectl create deployment web --image=nginx:1.27 --replicas=2
kubectl set image deploy/web nginx=nginx:1.28     # new version
kubectl rollout status deploy/web                 # wait until it's done
kubectl rollout history deploy/web
kubectl rollout undo deploy/web                   # back to the previous one
kubectl rollout restart deploy/web                # new pods, same version
kubectl scale deploy/web --replicas=5
kubectl autoscale deploy/web --min=2 --max=10 --cpu-percent=80

kubectl expose deploy web --port=80 --target-port=8080
kubectl get endpoints web                         # no IPs = no pod matches or is Ready
kubectl run tmp --rm -it --image=busybox -- wget -qO- http://web:80

kubectl create configmap settings --from-file=app.conf
kubectl create secret generic db --from-literal=user=app --from-file=password=./pw.txt
kubectl get secret db -o jsonpath='{.data.password}' | base64 -d
kubectl describe secret db                        # keys, without the values

kubectl get pod web-7d9f8 -o yaml                 # the full object
kubectl get pods -o name                          # just names, for scripts
kubectl get pods -o jsonpath='{.items[*].metadata.name}'
kubectl get pods -o custom-columns=NAME:.metadata.name,NODE:.spec.nodeName
kubectl get pods --sort-by=.metadata.creationTimestamp
kubectl get pods --field-selector=status.phase=Failed

kubectl top nodes                       # needs metrics-server
kubectl top pods -A --sort-by=memory
kubectl describe node worker-2          # capacity, conditions, what runs there
kubectl cordon worker-2                 # no new pods here
kubectl drain worker-2 --ignore-daemonsets
kubectl uncordon worker-2

kubectl delete pod web-7d9f8                       # a Deployment makes a new one
kubectl delete pods --field-selector=status.phase=Failed
kubectl delete pod web-7d9f8 --grace-period=0 --force   # stuck pods: last resort