https://drive.google.com/file/d/1FHkmwfdfCk3luxpZiid3_RgPJWvYpqeC/view?usp=sharing

🔍 YAML Breakdown

apiVersion: v1
kind: Pod
metadata:
  name: empty-pod
spec:
  containers:
  - name: boxone
    image: lovelearnlinux/webserver:v1
    volumeMounts:
    - mountPath: /var/www/html  # ← Where volume is mounted in container
      name: demo-volume
  volumes:
  - name: demo-volume           # ← Volume name (matches volumeMounts)
    emptyDir: {}                # ← Ephemeral storage on node

🔑 Key Insight:

emptyDir creates a temporary directory on the node that:

💡 Why mount to /var/www/html?

The lovelearnlinux/webserver:v1 image likely serves files from this directory.

→ emptyDir replaces the default content with an empty directory!

📌 When to Use emptyDir

Use Case Why
Scratch space Temporary files (e.g., sorting, processing)
Shared communication Share data between containers in a Pod
Cache directory Store non-critical cached data
Log aggregation Sidecar container reads logs from app container

⚠️ When NOT to use emptyDir:

🧪 k3s Lab: Test emptyDir Behavior

🔧 Step 1: Deploy the Pod

# Apply Pod
kubectl apply -f empty-dir.yaml

# Verify
kubectl get pods empty-pod

🔧 Step 2: Observe Empty Web Directory

# Check web content (should be empty!)
kubectl exec empty-pod -- ls /var/www/html
# (no output = empty directory)

# Try to access web server
kubectl port-forward empty-pod 8080:80 &
curl <http://localhost:8080>
# ✅ Returns empty response (no index.html)

🔍 Why?

The emptyDir overwrote the image’s default /var/www/html (which had index.html).

🔧 Step 3: Write Data to emptyDir

# Create a file in the volume
kubectl exec empty-pod -- sh -c "echo '<h1>Hello from emptyDir!</h1>' > /var/www/html/index.html"

# Verify
kubectl exec empty-pod -- cat /var/www/html/index.html

# Test via port-forward
curl <http://localhost:8080>
# ✅ "Hello from emptyDir!"

🔧 Step 4: Simulate Container Restart (Data Survives)

# Kill the container (not the Pod!)
kubectl exec empty-pod -- kill 1

# Wait for container to restart
kubectl get pods empty-pod

# Check if data survives
curl <http://localhost:8080>
# ✅ Still "Hello from emptyDir!" → data survived container restart!