Kubernetes Cheat Sheet

kubectl get pods -A
kubectl describe pod orders-7c9-xyz
kubectl logs -f orders-7c9-xyz -c orders
kubectl exec -it orders-7c9-xyz -- sh
kubectl delete pod orders-7c9-xyz   # forces re-schedule

apiVersion: apps/v1
kind: Deployment
metadata: { name: orders }
spec:
  replicas: 3
  selector: { matchLabels: { app: orders } }
  template:
    metadata: { labels: { app: orders } }
    spec:
      containers:
      - name: orders
        image: ghcr.io/acme/orders:1.4.0
        ports: [{ containerPort: 8080 }]
        readinessProbe: { httpGet: { path: /actuator/health/readiness, port: 8080 } }
        resources:
          requests: { cpu: 200m, memory: 512Mi }
          limits:   { cpu: 1,    memory: 1Gi }

# kubectl
kubectl apply -f orders.yaml
kubectl rollout status deploy/orders
kubectl rollout undo   deploy/orders

apiVersion: v1
kind: Service
metadata: { name: orders }
spec:
  selector: { app: orders }
  ports: [{ port: 80, targetPort: 8080 }]
  type: ClusterIP    # or LoadBalancer / NodePort

kubectl port-forward svc/orders 8080:80

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: orders
  annotations: { cert-manager.io/cluster-issuer: letsencrypt }
spec:
  tls: [{ hosts: [api.acme.com], secretName: api-tls }]
  rules:
  - host: api.acme.com
    http:
      paths:
      - path: /orders
        pathType: Prefix
        backend: { service: { name: orders, port: { number: 80 } } }

kubectl create configmap orders-conf \
  --from-literal=FEATURE_FLAG_NEW=true

kubectl create secret generic db-creds \
  --from-literal=DB_PASSWORD=s3cret

# Mount in a Pod spec
envFrom:
- configMapRef: { name: orders-conf }
- secretRef:    { name: db-creds }

helm repo add bitnami https://charts.bitnami.com/bitnami
helm repo update

helm upgrade --install orders ./chart \
  -n payments --create-namespace \
  -f values.prod.yaml

helm diff upgrade orders ./chart -f values.prod.yaml
helm list -A
helm rollback orders 1

kubectl config get-contexts
kubectl config use-context prod-eu
kubectl get all -n payments
kubectl top pods -n payments
kubectl explain deployment.spec.strategy
kubectl debug node/ip-10-0-1-23 -it --image=busybox