PVC Migration in Kubernetes: How to Move Persistent Data Across Availability Zones

Introduction

In today’s IT world, data is everything, and in the era of DevOps, requirements change frequently. Let’s assume your application is running on one Kubernetes cluster, and for some reason, you need to migrate a PVC (Persistent Volume Claim) from this cluster to another Kubernetes cluster in a different availability zone without losing data.

In this guide, we’ll cover how to migrate PVC across availability zones in Kubernetes, the commands to use, and best practices for cloud providers like AWS.

What are PV, PVC, and Storage Volume?

• Persistent Volume (PV): A storage resource in Kubernetes that exists independently of the pod lifecycle. Even if the pod is deleted, the data remains in the PV.
• Persistent Volume Claim (PVC): A request for storage by a user, specifying size, access mode, and other configurations.
• Storage Volume: A virtual disk (block storage) provided by your cloud provider for persistent data storage.

Steps to Migrate PVC Across Availability Zones

1. Identify the PVC Attached to Your Pod

kubectl get po <pod-name> -o yaml

2. Find the PV Bound to the PVC

kubectl get pvc <pvc-name>

3. Get the Volume ID and Zone Info

kubectl describe pv <pv-name>

Check the annotations for the volume ID and the availability zone.

4. Snapshot and Create a New Volume

• Create a snapshot of the existing volume in your cloud provider console (e.g., AWS EBS Snapshot).
• Create a new volume from that snapshot in the desired availability zone.
• Add the label:

KubernetesCluster: <clustername>

Note the new volume ID.

5. Create a PV from the New Volume

apiVersion: v1
kind: PersistentVolume
metadata:
  name: my-pv
  labels:
    type: persistent-volume
spec:
  capacity:
    storage: 3Gi
  accessModes:
    - ReadWriteOnce
  awsElasticBlockStore:
    volumeID: <YOUR STORAGE VOLUME ID>
    fsType: ext4

6. Create a PVC Bound to the New PV

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: my-pvc
  labels:
    type: persistent-volume-claim
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 3Gi
  selector:
    matchLabels:
      type: persistent-volume

7. Attach PVC to a Pod

apiVersion: v1
kind: Pod
metadata:
  name: pv-pod
spec:
  volumes:
    - name: my-pv
      persistentVolumeClaim:
        claimName: my-pvc
  containers:
    - name: task-pv-container
      image: nginx
      ports:
        - containerPort: 80
          name: "http-server"
      volumeMounts:
        - mountPath: "/usr/share/nginx/html"
          name: my-pv

Congratulations! 🎉 You have successfully migrated a PVC from one Kubernetes cluster to another across different availability zones.

Best Practices for PVC Migration

• Always take backups before initiating migration.
• Use ReadWriteOnce volumes for single-node attachment; adjust for ReadWriteMany if needed.
• Check volume type compatibility in the target availability zone.
• For faster automation, consider Kubernetes VolumeSnapshot APIs if your cloud provider supports them.

Conclusion

PVC migration in Kubernetes is a crucial skill for moving persistent data across clusters or availability zones without downtime or data loss. By carefully identifying PVC/PV details, creating snapshots, and provisioning new volumes, you can ensure a smooth migration process. This approach not only supports disaster recovery but also enables scaling, multi-region deployments, and infrastructure upgrades while keeping workloads resilient and highly available.

FAQ

Shubham Kumar

Shubham is a DevOps engineer and has worked with multiple organizations. He has worked extensively with cloud technologies including AWS, Kubernetes, and ArgoCD.