Delete the pod. The file stays.

Read the step before copying. Bash commands belong in Git Bash on Windows or Azure Cloud Shell set to Bash; PowerShell uses different syntax. A JSON, YAML, Bicep or application-code example belongs in the named file, not directly at the terminal prompt. Follow any shell-specific instructions below.

Keep the same terminal open so earlier variables remain available. Copy one complete command block without the terminal's $ prompt. A backslash continues a command onto the next line. If Bash shows a lone >, it is waiting for the rest of a quote, command or file block. Finish the complete block; if the paste was incomplete, press Ctrl+C and copy it again. Do not paste the next step into an unfinished command.

A line such as RG="training-group" stores a value without printing it. Output captured with $(...) is also stored; a blank screen alone does not prove failure. A sleep deliberately waits, and -o none suppresses normal output. Wait for your normal prompt, then run the step's checkpoint. After an error, stop and keep the exact command and message; later steps cannot repair a missing resource. Never share passwords, access tokens or secret values in a screenshot.

Delete a pod and its container's writable layer goes with it. An emptyDir survives a container restart inside the same pod but disappears when the pod is removed. To keep this lab's file across pod replacement, create a separate PersistentVolumeClaim (PVC) backed by an Azure Disk through the managed-csi StorageClass. You will write a file, delete the pod, and read it from a new one. Then two pods on this single node will mount the same claim: ReadWriteOnce limits read-write access to one node, not one pod.

Replace the pod. Keep the claim.

If you still have the cluster from Your first AKS cluster, skip to get-credentials. Otherwise recreate it with the identical command.

# Windows/Git Bash: stop it mangling /subscriptions/... arguments (harmless on macOS/Linux)
export MSYS_NO_PATHCONV=1

RG="campux-lab-aks-rg"
az group create -n "$RG" -l eastus

# same command as the first-cluster lab: free control plane, one small node
# if Azure says this size "is not allowed in your subscription", the same error lists the sizes
# that are; pick a 2-vCPU one from that list (Standard_D2as_v4 worked for us in October 2026)
az aks create -n campux-aks -g "$RG" \
  --tier free \
  --node-count 1 \
  --node-vm-size Standard_D2as_v4 \
  --enable-managed-identity \
  --generate-ssh-keys

az aks get-credentials -n campux-aks -g "$RG"
kubectl get nodes
kubectl get storageclass

Request 1Gi through the built-in disk class, then mount the claim into a pod at /data. Azure may provision and bill a larger disk tier than the requested capacity.

kubectl create namespace storage-demo

cat > pvc.yaml <<'EOF'
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: demo-pvc
  namespace: storage-demo
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: managed-csi
  resources:
    requests:
      storage: 1Gi
EOF

kubectl apply -f pvc.yaml
kubectl get pvc demo-pvc -n storage-demo   # STATUS: Pending

Run a pod that mounts the claim, write a file to it, confirm the claim is now Bound, then delete the pod outright.

This block includes a deliberate wait. Leave this terminal open until the normal prompt returns; a wait is not proof that access has propagated.

cat > pod-v1.yaml <<'EOF'
apiVersion: v1
kind: Pod
metadata:
  name: writer
  namespace: storage-demo
spec:
  containers:
  - name: app
    image: busybox:1.28
    command: ["sh", "-c", "echo 'the disk remembers this' > /data/note.txt && sleep 3600"]
    volumeMounts:
    - name: data
      mountPath: /data
  volumes:
  - name: data
    persistentVolumeClaim:
      claimName: demo-pvc
EOF

kubectl apply -f pod-v1.yaml
kubectl wait --for=condition=Ready pod/writer -n storage-demo --timeout=120s
kubectl get pvc demo-pvc -n storage-demo
kubectl exec writer -n storage-demo -- cat /data/note.txt

kubectl delete pod writer -n storage-demo
kubectl get pod writer -n storage-demo   # -> Error from server (NotFound)

Start a new pod — different name, does not write anything — that mounts the same claim and reads the file the deleted pod left behind.

This block includes a deliberate wait. Leave this terminal open until the normal prompt returns; a wait is not proof that access has propagated.

cat > pod-v2.yaml <<'EOF'
apiVersion: v1
kind: Pod
metadata:
  name: reader
  namespace: storage-demo
spec:
  containers:
  - name: app
    image: busybox:1.28
    command: ["sh", "-c", "sleep 3600"]
    volumeMounts:
    - name: data
      mountPath: /data
  volumes:
  - name: data
    persistentVolumeClaim:
      claimName: demo-pvc
EOF

kubectl apply -f pod-v2.yaml
kubectl wait --for=condition=Ready pod/reader -n storage-demo --timeout=120s
kubectl exec reader -n storage-demo -- cat /data/note.txt

With reader still running and holding the claim, try to schedule a second pod that mounts the same PVC.

This block includes a deliberate wait. Leave this terminal open until the normal prompt returns; a wait is not proof that access has propagated.

cat > pod-v3.yaml <<'EOF'
apiVersion: v1
kind: Pod
metadata:
  name: second-reader
  namespace: storage-demo
spec:
  containers:
  - name: app
    image: busybox:1.28
    command: ["sh", "-c", "sleep 3600"]
    volumeMounts:
    - name: data
      mountPath: /data
  volumes:
  - name: data
    persistentVolumeClaim:
      claimName: demo-pvc
EOF

kubectl apply -f pod-v3.yaml
kubectl get pod second-reader -n storage-demo -w   # Ctrl-C once it stops changing

kubectl delete pod reader second-reader -n storage-demo

Delete the pods first, then the PVC and namespace. The built-in class normally uses a Delete reclaim policy, but confirm the disk is gone. The final group deletion also removes the cluster used by the first-cluster lab; skip it if you deliberately want to retain that cluster and accept its ongoing charges.

kubectl delete pvc demo-pvc -n storage-demo
kubectl delete namespace storage-demo

az group delete -n campux-lab-aks-rg --yes --no-wait
az group exists -n campux-lab-aks-rg      # -> false once complete

You created a PVC backed by Azure Disk, wrote a file, deleted its pod, and read the same file from a new pod. You also mounted the claim from two pods on the same node, showing that RWO is a node limit rather than a one-pod lock. This single-node exercise does not test what happens when a second node requests the disk.