Overview:

Scaling stateful applications requires specialized strategies to preserve data consistency and ordering.

StatefulSet Scaling:

1. Manually Scale StatefulSets:

   kubectl scale statefulset <statefulset-name> --replicas=3

2. Scaling with Persistent Volumes (PVs):

   • Ensure that PVs are dynamically provisioned for each Pod.

Example:

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

Activity:

Deploy a StatefulSet with dynamic volume provisioning and manually scale the Pods.