Troubleshooting

Get all abnormal pods

kubectl get pods --field-selector "status.phase!=Running,status.phase!=Succeeded"

Connect to a service on a local port

kubectl port-forward service/blog 12345:http

Get a shell on a temporary pod

kubectl run -it --rm --image alpine tmp -- /bin/sh

Add a temporary container to a deployment and get a shell

kubectl patch deployment/backend -p '{"spec":{"template":{"spec":{"containers":[{"name":"tmp","image":"alpine","std-in":true,"tty":true}]}}}}'
kubectl exec -it deployment/backend -c tmp -- /bin/sh

kubectl patch deployment/backend -p "$(curl https://k8sh8.com/patch/alpine)"
kubectl patch deployment/backend -p "$(curl https://k8sh8.com/patch/busybox)"

Add a temporary pod that mounts a PersistentVolumeClaim

kubectl run -it --rm --image alpine tmp --override-type 'strategic' --overrides '{"spec":{"containers":[{"name":"tmp","volumeMounts":[{"name":"v","mountPath":"/mnt"}]}],"volumes":[{"name":"v","persistentVolumeClaim":{"claimName":"database"}}]}}' -- /bin/sh

Blunt Force

Remove resource limitations from a deployment

kubectl set resources deployment/backend --limits 'memory=0' --requests 'memory=0'

Restart all pods for a deployment

kubectl rollout restart deployment/backend

Terminate a specific container within a pod

kubectl exec backend -c database -- /bin/sh -c "kill 1"

Skip finalizers for a namespace stuck in Terminating

kubectl patch ns/blog -p '{"spec":{"finalizers":[]}}' --dry-run=client -o json | kubectl replace --raw "/api/v1/namespaces/blog/finalize" -f -

Labels & Annotations

Remove an annotation

kubectl annotate deployment/backend meta.helm.sh/release-name-

Information

Get all objects of all types in a namespace

kubectl -n blog get $(kubectl api-resources --namespaced=true --verbs get -o name | tr '\n' ',')pods

Get all non-namespaced objects in the cluster

kubectl get $(kubectl api-resources --namespaced=false --verbs get -o name | tr '\n' ',')nodes

Secrets

kubectl get secret/database -o go-template='{{ range $k,$v := .data }}{{ $k }}: {{ $v | base64decode }}{{ "\n" }}{{ end }}'

kubectl get secret/database -o go-template="$(curl https://k8sh8.com/template/secret)"

Certificates

Force cert-manager certificate renewal

kubectl patch certificate/frontend-certificate --subresource status --type merge -p '{"status":{"conditions":[{"type":"Issuing","status":"True"}]}}'

kubectl patch certificate/frontend-certificate --subresource status --type merge -p "$(curl https://k8sh8.com/patch/renew)"

Get certificate information

kubectl get secret/frontend-certificate -o go-template='{{ index .data "tls.crt" | base64decode }}' | openssl x509 -text

kubectl get secret/frontend-certificate -o go-template="$(curl https://k8sh8.com/template/cert)" | openssl x509 -text

Get private key information

kubectl get secret/frontend-certificate -o go-template='{{ index .data "tls.key" | base64decode }}' | openssl rsa -text

kubectl get secret/frontend-certificate -o go-template="$(curl https://k8sh8.com/template/key)" | openssl rsa -text

Helm

Force Helm ownership of an object

kubectl annotate deployment/frontend --overwrite app.kubernetes.io/managed-by=Helm meta.helm.sh/release-name=blog meta.helm.sh/release-namespace=blog