Kubernetes Cheatsheet

# Cluster info
kubectl cluster-info
kubectl get nodes
kubectl describe node NODE_NAME
kubectl top nodes

# Context & config
kubectl config view
kubectl config current-context
kubectl config use-context CONTEXT_NAME
kubectl config set-context --current --namespace=NAMESPACE

# Create resources
kubectl create -f FILE.yaml
kubectl apply -f FILE.yaml
kubectl apply -f DIR/
kubectl create deployment NAME --image=IMAGE

# Get resources
kubectl get all
kubectl get pods -o wide
kubectl get svc --all-namespaces
kubectl get pods -l app=nginx

# Update resources
kubectl edit TYPE/NAME
kubectl patch TYPE NAME -p '{"spec":{"replicas":3}}'
kubectl set image deployment/NAME CONTAINER=IMAGE:TAG
kubectl scale deployment NAME --replicas=5

# Delete resources
kubectl delete -f FILE.yaml
kubectl delete TYPE NAME
kubectl delete pods --all
kubectl delete ns NAMESPACE

# Pod interaction
kubectl exec -it POD_NAME -- /bin/bash
kubectl exec POD_NAME -- COMMAND
kubectl attach POD_NAME -c CONTAINER
kubectl cp POD_NAME:/path/file ./local/path

# Pod logs
kubectl logs POD_NAME
kubectl logs -f POD_NAME
kubectl logs POD_NAME -c CONTAINER
kubectl logs --previous POD_NAME

# Port forwarding
kubectl port-forward POD_NAME 8080:80
kubectl port-forward svc/SERVICE 8080:80
kubectl port-forward deployment/NAME 8080:80
kubectl proxy

# Debug & describe
kubectl describe pod POD_NAME
kubectl get events --sort-by='.lastTimestamp'
kubectl debug POD_NAME -it --image=busybox
kubectl top pod POD_NAME

# Deployment management
kubectl create deployment NAME --image=IMAGE
kubectl expose deployment NAME --port=80 --type=LoadBalancer
kubectl autoscale deployment NAME --min=2 --max=10
kubectl rollout status deployment/NAME

# Rollout operations
kubectl rollout history deployment/NAME
kubectl rollout undo deployment/NAME
kubectl rollout undo deployment/NAME --to-revision=2
kubectl rollout pause/resume deployment/NAME

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
  labels:
    app: nginx
    tier: frontend
spec:
  containers:
  - name: nginx
    image: nginx:1.21
    ports:
    - containerPort: 80
      name: http
    resources:
      requests:
        memory: "64Mi"
        cpu: "250m"
      limits:
        memory: "128Mi"
        cpu: "500m"
    livenessProbe:
      httpGet:
        path: /
        port: 80
      initialDelaySeconds: 30
      periodSeconds: 10
    readinessProbe:
      httpGet:
        path: /
        port: 80
      initialDelaySeconds: 5
      periodSeconds: 5

apiVersion: apps/v1
kind: Deployment
metadata:
  name: app-deployment
  labels:
    app: myapp
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: app
        image: myapp:1.0.0
        ports:
        - containerPort: 8080
        env:
        - name: ENV_VAR
          value: "production"
        - name: SECRET_KEY
          valueFrom:
            secretKeyRef:
              name: app-secret
              key: api-key
        volumeMounts:
        - name: config
          mountPath: /etc/config
      volumes:
      - name: config
        configMap:
          name: app-config
---
apiVersion: v1
kind: Service
metadata:
  name: app-service
spec:
  selector:
    app: myapp
  type: ClusterIP
  ports:
  - port: 80
    targetPort: 8080
    protocol: TCP

apiVersion: v1
kind: Service
metadata:
  name: nginx-headless
  labels:
    app: nginx
spec:
  ports:
  - port: 80
    name: web
  clusterIP: None
  selector:
    app: nginx
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  serviceName: "nginx-headless"
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.21
        ports:
        - containerPort: 80
          name: web
        volumeMounts:
        - name: www
          mountPath: /usr/share/nginx/html
  volumeClaimTemplates:
  - metadata:
      name: www
    spec:
      accessModes: [ "ReadWriteOnce" ]
      storageClassName: "standard"
      resources:
        requests:
          storage: 1Gi

# Job
apiVersion: batch/v1
kind: Job
metadata:
  name: batch-job
spec:
  completions: 3
  parallelism: 2
  backoffLimit: 4
  template:
    spec:
      containers:
      - name: worker
        image: busybox
        command: ['sh', '-c', 'echo "Processing..." && sleep 30']
      restartPolicy: Never
---
# CronJob
apiVersion: batch/v1
kind: CronJob
metadata:
  name: scheduled-job
spec:
  schedule: "*/5 * * * *"  # Every 5 minutes
  jobTemplate:
    spec:
      template:
        spec:
          containers:
          - name: task
            image: busybox
            command:
            - /bin/sh
            - -c
            - date; echo "Running scheduled task"
          restartPolicy: OnFailure

# ConfigMap
apiVersion: v1
kind: ConfigMap
metadata:
  name: app-config
data:
  database_url: "postgres://localhost:5432/mydb"
  app.properties: |
    server.port=8080
    logging.level=INFO
---
# Secret
apiVersion: v1
kind: Secret
metadata:
  name: app-secret
type: Opaque
data:
  username: YWRtaW4=  # base64 encoded 'admin'
  password: cGFzc3dvcmQ=  # base64 encoded 'password'
---
# Or using stringData (automatically base64 encoded)
apiVersion: v1
kind: Secret
metadata:
  name: app-secret-string
type: Opaque
stringData:
  username: admin
  password: password

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: app-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
    cert-manager.io/cluster-issuer: letsencrypt-prod
spec:
  ingressClassName: nginx
  tls:
  - hosts:
    - app.example.com
    secretName: app-tls
  rules:
  - host: app.example.com
    http:
      paths:
      - path: /api
        pathType: Prefix
        backend:
          service:
            name: api-service
            port:
              number: 8080
      - path: /
        pathType: Prefix
        backend:
          service:
            name: frontend-service
            port:
              number: 80

# Resource investigation
kubectl get events --sort-by='.lastTimestamp'
kubectl get pods --all-namespaces -o wide
kubectl describe node NODE_NAME | grep -A 5 "Allocated resources"
kubectl top pods --all-namespaces

# Network debugging
kubectl exec -it POD -- nslookup kubernetes.default
kubectl exec -it POD -- ping SERVICE_NAME
kubectl exec -it POD -- curl -v http://SERVICE:PORT
kubectl get networkpolicies

# Storage issues
kubectl get pv
kubectl get pvc --all-namespaces
kubectl describe pvc PVC_NAME
kubectl get storageclass

# RBAC debugging
kubectl auth can-i VERB RESOURCE
kubectl auth can-i --list
kubectl get rolebindings,clusterrolebindings --all-namespaces
kubectl describe sa SERVICE_ACCOUNT

# Basic JSONPath
kubectl get pods -o jsonpath='{.items[*].metadata.name}'
kubectl get nodes -o jsonpath='{.items[*].status.addresses[?(@.type=="ExternalIP")].address}'
kubectl get pods -o jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.status.phase}{"\n"}{end}'

# Custom columns
kubectl get pods -o custom-columns=NAME:.metadata.name,STATUS:.status.phase
kubectl get nodes -o custom-columns=NAME:.metadata.name,CPU:.status.capacity.cpu
kubectl get pv -o custom-columns=NAME:.metadata.name,CAPACITY:.spec.capacity.storage

# Filtering & sorting
kubectl get pods --field-selector status.phase=Running
kubectl get events --sort-by='.metadata.creationTimestamp'
kubectl get pods --sort-by='.status.containerStatuses[0].restartCount'

# Complex queries
kubectl get pods -o jsonpath='{.items[?(@.status.phase!="Running")].metadata.name}'
kubectl get svc -o jsonpath='{.items[?(@.spec.type=="LoadBalancer")].status.loadBalancer.ingress[0].ip}'
kubectl get pods -o jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.spec.containers[*].image}{"\n"}{end}'

# Basic aliases
alias k='kubectl'
alias kgp='kubectl get pods'
alias kgs='kubectl get svc'
alias kgd='kubectl get deployment'
alias kaf='kubectl apply -f'
alias kdel='kubectl delete'
alias kdes='kubectl describe'
alias klog='kubectl logs'
alias kex='kubectl exec -it'

# Namespace aliases
alias kgpa='kubectl get pods --all-namespaces'
alias kgsw='kubectl get svc --all-namespaces -o wide'
alias kn='kubectl config set-context --current --namespace'

# Quick commands
alias krun='kubectl run tmp --image=busybox -it --rm --restart=Never --'
alias kdebug='kubectl run debug --image=nicolaka/netshoot -it --rm --restart=Never --'
alias kport='kubectl port-forward'
alias ktop='kubectl top'

# Context management
alias kctx='kubectl config current-context'
alias kuse='kubectl config use-context'

# Resource watching
alias kwatch='kubectl get pods -w'

# Bash
source <(kubectl completion bash)
echo "source <(kubectl completion bash)" >> ~/.bashrc

# Zsh
source <(kubectl completion zsh)
echo "source <(kubectl completion zsh)" >> ~/.zshrc

# Fish
kubectl completion fish | source
echo "kubectl completion fish | source" >> ~/.config/fish/config.fish

# PowerShell
kubectl completion powershell | Out-String | Invoke-Expression