Overview:

StatefulSets are designed to manage stateful applications, where each Pod requires a stable identity and persistent storage.

Key Features:

• Stable Pod Names: Pods get persistent DNS names.

• Ordered Deployment and Scaling: Ensures Pods are started or stopped in order.

• Persistent Storage: Retains data even if Pods are deleted.

Example StatefulSet YAML Manifest:

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  serviceName: "nginx"
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:latest
        ports:
        - containerPort: 80
        volumeMounts:
        - name: www
          mountPath: /usr/share/nginx/html
  volumeClaimTemplates:
  - metadata:
      name: www
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 1Gi

Steps to Deploy:

1. Apply the StatefulSet:

   kubectl apply -f statefulset.yaml

2. Verify Pods:

   kubectl get pods -l app=nginx

3. Check Persistent Volumes:

   kubectl get pvc

Activity:

Deploy a StatefulSet using the provided manifest. Verify that each Pod has a stable identity and persistent storage.