Kubectl CLI

kubectl (Kubernetes CLI)

Official CLI for Kubernetes. Manage clusters, deployments, pods, services, and configurations.

• Official repo: https://github.com/kubernetes/kubectl
• Docs: https://kubernetes.io/docs/reference/kubectl/

Configuration

kubectl config current-context            # Show active cluster
kubectl config get-contexts               # List all contexts
kubectl config use-context my-cluster     # Switch context
kubectl cluster-info                      # Show cluster info

Common Commands

Viewing Resources

kubectl get pods                          # List pods in default namespace
kubectl get pods -A                       # All namespaces
kubectl get pods -n my-namespace          # Specific namespace
kubectl get deployments
kubectl get services
kubectl get nodes
kubectl get all                           # All resource types
kubectl describe pod my-pod               # Detailed pod info
kubectl top pods                          # Resource usage

Deploying

kubectl apply -f manifest.yaml            # Apply config
kubectl apply -f ./k8s/                   # Apply directory of configs
kubectl create deployment my-app --image=my-app:latest
kubectl set image deployment/my-app my-app=my-app:v2   # Update image
kubectl rollout status deployment/my-app
kubectl rollout undo deployment/my-app    # Rollback
kubectl scale deployment/my-app --replicas=3

Debugging

kubectl logs my-pod                       # Pod logs
kubectl logs my-pod -c my-container       # Specific container
kubectl logs -f my-pod --tail=100         # Follow logs
kubectl exec -it my-pod -- bash           # Shell into pod
kubectl port-forward my-pod 8080:80       # Port forward
kubectl get events --sort-by='.lastTimestamp'

Managing Resources

kubectl delete pod my-pod
kubectl delete -f manifest.yaml
kubectl edit deployment my-app
kubectl patch deployment my-app -p '{"spec":{"replicas":2}}'

Agent Best Practices

• Use -o json or -o jsonpath for structured output
• Always specify namespace with -n to avoid mistakes
• Use kubectl diff -f manifest.yaml before apply to preview changes
• Use --dry-run=client -o yaml to generate manifests without applying
• Use kubectl get pods -o wide for node placement info
• Watch resources with kubectl get pods -w for real-time updates
• Use labels: kubectl get pods -l app=my-app

Example Workflows

Check deployment health

kubectl rollout status deployment/my-app
kubectl get pods -l app=my-app -o json | jq '.items[] | {name: .metadata.name, status: .status.phase}'

Debug a crashing pod

kubectl describe pod my-pod | tail -20
kubectl logs my-pod --previous --tail=50