Step‑by‑Step Guide to Deploying and Managing a Kubernetes Web Application

1. Create a YAML template

kubectl create deployment web --image=nginx --dry-run -o yaml > web.yaml

2. Edit the template

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: web
  name: web
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web
  template:
    metadata:
      labels:
        app: web
    spec:
      containers:
      - image: zhangfan5391621/java-demo
        name: java

3. Deploy the pod

kubectl apply -f web.yaml
kubectl logs web-dc77dd8db-hhrxz # check logs

kubectl get deploy # view deployments

4. Create a Service

kubectl expose --name=web deployment web --port=80 --target-port=8080 --type=NodePort
kubectl get service # view service ports

Access the application via any node IP and the assigned NodePort (e.g., 30909).

5. Upgrade the service (rolling update)

kubectl set image deployment web java=nginx
# or edit the service directly if configuration changes
http://192.168.106.103:30909/ # access the updated version

6. Roll back the deployment

kubectl rollout history deployment web # view revision history

kubectl rollout undo deployment web # revert to previous version
# optionally specify a revision: --revision=3

7. Scale replicas up or down

kubectl scale deployment web --replicas=5 # expand to 5 pods
kubectl scale deployment web --replicas=2 # shrink to 2 pods

After scaling, the number of running replicas reflects the new count.

8. Delete the Service and Deployment

kubectl delete deployment/web
kubectl delete svc/web