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Latchu@DevOps
Latchu@DevOps

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🎯 Scenario #8 — Deploy a ReplicaSet and Verify Self-Healing of Pods in Kubernetes

#kubernetes #devops #cicd #containers

ReplicaSets ensure that the desired number of Pods is always running.

If a Pod is deleted manually → ReplicaSet AUTO-CREATES a new one.

✅ Step 1 — Create ReplicaSet YAML 

# rs-nginx.yaml
apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: nginx-rs
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx-demo
  template:
    metadata:
      labels:
        app: nginx-demo
    spec:
      containers:
      - name: nginx
        image: nginx:1.25
        ports:
        - containerPort: 80
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Apply:

kubectl apply -f rs-nginx.yaml
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✅ Step 2 — Verify ReplicaSet + Pods 

kubectl get rs
kubectl get pods -o wide
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You should see 3 Pods with random hash-like suffixes:

nginx-rs-7dd8f995f5-rkzfx
nginx-rs-7dd8f995f5-pxbgl
nginx-rs-7dd8f995f5-7cj2p
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✅ Step 3 — Test Self-Healing (Delete a Pod)

Pick any one:

kubectl delete pod nginx-rs-7dd8f995f5-rkzfx
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Watch Pods:

kubectl get pods -w
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Expected behavior:

  • Deleted Pod goes away
  • ReplicaSet automatically creates a NEW pod
  • Count stays at 3 always

Example:

pod "nginx-rs-xxx" deleted
pod "nginx-rs-newxxx" created
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🎉 ReplicaSet self-healing verified!

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⚠️ Self-Healing Works Only If Labels Match Selector

If you edit the Pod labels:

kubectl label pod POD_NAME app-
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→ ReplicaSet stops managing it
→ Will create a replacement pod.

🔥 BONUS TEST — Scale ReplicaSet

Increase replicas:

kubectl scale rs nginx-rs --replicas=5
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Decrease:

kubectl scale rs nginx-rs --replicas=2
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— Latchu | Senior DevOps & Cloud Engineer

☁️ AWS | GCP | ☸️ Kubernetes | 🔐 Security | ⚡ Automation
📌 Sharing hands-on guides, best practices & real-world cloud solutions

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