kubectl Basics — Practical Commands for Pods, Deployments, and Services

# Install kubectl (Linux)
curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
chmod +x kubectl && mv kubectl /usr/local/bin/

# Check cluster contexts
kubectl config get-contexts
kubectl config use-context my-cluster

# Current context
kubectl config current-context

# List Pods
kubectl get pods
kubectl get pods -n kube-system        # Specify a namespace
kubectl get pods -A                    # All namespaces
kubectl get pods -o wide               # Include node information

# Pod details
kubectl describe pod my-pod

# Pod logs
kubectl logs my-pod
kubectl logs my-pod -c my-container   # Multi-container
kubectl logs -f my-pod                 # Follow (live)

# Exec into a Pod
kubectl exec -it my-pod -- bash
kubectl exec -it my-pod -c my-container -- sh

# Delete a Pod
kubectl delete pod my-pod

# Create a Deployment
kubectl create deployment nginx --image=nginx:latest --replicas=3

# List Deployments and check status
kubectl get deployments
kubectl rollout status deployment/nginx

# Update the image
kubectl set image deployment/nginx nginx=nginx:1.25

# Rollback
kubectl rollout undo deployment/nginx
kubectl rollout undo deployment/nginx --to-revision=2

# Scale
kubectl scale deployment nginx --replicas=5

# Rolling update history
kubectl rollout history deployment/nginx

# ClusterIP (internal traffic)
kubectl expose deployment nginx --port=80 --target-port=80

# NodePort (external access)
kubectl expose deployment nginx \
  --type=NodePort --port=80 --target-port=80

# LoadBalancer (cloud)
kubectl expose deployment nginx \
  --type=LoadBalancer --port=80

# List Services
kubectl get services
kubectl get svc

# Port-forward (local testing)
kubectl port-forward service/nginx 8080:80

# deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
  labels:
    app: my-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: my-app
        image: my-app:1.0
        ports:
        - containerPort: 3000
        resources:
          requests:
            memory: "64Mi"
            cpu: "250m"
          limits:
            memory: "128Mi"
            cpu: "500m"

kubectl apply -f deployment.yaml
kubectl delete -f deployment.yaml

# List all resources
kubectl get all -n my-namespace

# Filter by label
kubectl get pods -l app=nginx

# Check events (troubleshooting)
kubectl get events --sort-by='.lastTimestamp'

# Node status
kubectl get nodes -o wide
kubectl top nodes

# Pod resource usage
kubectl top pods

# ConfigMap / Secret
kubectl get configmap
kubectl get secret
kubectl describe secret my-secret