Kubernetes cheat sheet

Cluster used in this module: kind. Client: kubectl. Objects: README.

kind

kind create cluster --name learn
kind get clusters
kind delete cluster --name learn
kubectl cluster-info
kubectl config current-context          # expect kind-learn

Apply and inspect

kubectl apply -f examples/nginx-deployment.yaml
kubectl apply -f examples/nginx-service.yaml
kubectl get deploy,po,svc
kubectl get pods -o wide
kubectl get pods --show-labels
kubectl describe pod <pod>
kubectl get events --sort-by='.lastTimestamp'

Debug a Pod that is not Ready

kubectl describe pod <pod>              # Events at the bottom
kubectl logs <pod>
kubectl logs <pod> -c <container>
kubectl logs deploy/nginx --previous
kubectl exec -it deploy/nginx -- /bin/sh

Reach a ClusterIP from your laptop

kubectl port-forward svc/nginx 8080:80
curl -s -o /dev/null -w "%{http_code}\n" http://127.0.0.1:8080

Inside the cluster the DNS name is nginx.default.svc.cluster.local.

Scale and roll out

kubectl scale deploy/nginx --replicas=3
kubectl set image deploy/nginx nginx=nginx:1.27-alpine
kubectl rollout status deploy/nginx
kubectl rollout history deploy/nginx
kubectl rollout undo deploy/nginx
kubectl rollout restart deploy/nginx

Generate YAML without applying

kubectl create deployment nginx --image=nginx:1.27-alpine --dry-run=client -o yaml
kubectl create configmap app-config --from-literal=APP_COLOR=blue --dry-run=client -o yaml

Namespaces and RBAC

kubectl create namespace learn
kubectl apply -n learn -f examples/nginx-deployment.yaml
kubectl get pods -A
kubectl auth can-i get pods --as=system:serviceaccount:default:log-reader

Objects (short)