https://drive.google.com/file/d/1HKmo-R__r1_zY8mbeMExjsTqKts86_x2/view?usp=sharing

🔍 YAML Breakdown

apiVersion: v1
kind: Pod
metadata:
  name: nnappone
  namespace: learning
  labels:
    app: nnappone
spec:
  containers:
    - name: crackone-app
      image: lovelearnlinux/webserver:v1
      lifecycle:
        postStart:
          exec:
            command: ["/bin/sh", "-c", "useradd crackone -p redhat"]
        preStop:
          exec:
            command: ["/bin/sh","-c","rm -rf /home/crackone; userdel crackone"]

🔑 Key Insight:

• postStart: Runs immediately after container starts (but not guaranteed to run before app starts!)
• preStop: Runs immediately before container terminates (graceful shutdown)

⚠️ Critical Note:

postStart runs asynchronously with the container’s main process.

→ Your app might start before postStart finishes!

📌 When Lifecycle Hooks Run

🎯 Your Example:

• postStart: Creates a user crackone
• preStop: Deletes the user and home directory

💡 Why preStop matters:

Without it, user data would linger after Pod deletion (in container filesystem).

🧪 k3s Lab: Observe Lifecycle Hooks

🔧 Step 1: Create Namespace & Deploy Pod

# Create namespace
kubectl create namespace learning

# Apply Pod
kubectl apply -f pod-simple-lifecycle-events.yml

# Wait for Pod to be ready
kubectl get pods -n learning

🔧 Step 2: Verify postStart Ran

# Check if user was created
kubectl exec nnappone -n learning -- cat /etc/passwd | grep crackone

# ✅ Expected output:
# cracokone:x:1001:1001::/home/crackone:/bin/sh

# Check home directory
kubectl exec nnappone -n learning -- ls /home
# crackone

🔧 Step 3: Trigger preStop (Delete Pod)

# Delete Pod (triggers preStop)
kubectl delete pod nnappone -n learning

# Watch termination
kubectl get pods -n learning -w

🔍 How to verify preStop ran?

Since the Pod is deleted, we can’t check directly.

But we can test with a long-running preStop:

🔧 Step 4: Test preStop with Delay (Optional)