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feat(k8s): add tutorial for multi-az pvc migration
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‎tutorials/migrate-k8s-persistent-volumes-to-multi-az/index.mdx‎

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---
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meta:
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title: Migrating persistent volumes in a multi-zone Scaleway Kapsule cluster
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description: This tutorial provides information about how to migrate existing Persistent Volumes in a Scaleway Kapsule multi-zone cluster to enhance availability and fault tolerance.
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content:
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h1: Migrating persistent volumes in a multi-zone Scaleway Kapsul cluster
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paragraph: This tutorial provides information about how to migrate existing Persistent Volumes in a Scaleway Kapsule multi-zone cluster to enhance availability and fault tolerance.
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tags: kapsule elastic-metal migration persistent-volumes
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categories:
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- kubernetes
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dates:
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validation: 2025-01-30
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posted: 2025-01-30
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---
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Historically, Scaleway Kapsule clusters were single-zone, meaning workloads and their associated storage were confined to a single location. With the introduction of multi-zone support, distributing workloads across multiple zones can enhance availability and fault tolerance.
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This tutorial provides a generalized approach to migrating Persistent Volumes (PVs) from one zone to another in a Scaleway Kapsule multi-zone cluster, applicable to various applications.
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<Macro id="requirements" />
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- A Scaleway account logged into the [console](https://console.scaleway.com)
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- [Owner](/iam/concepts/#owner) status or [IAM permissions](/iam/concepts/#permission) allowing you to perform actions in the intended Organization
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- [Created a Kapsule cluster](/kubernetes/how-to/create-cluster/) with multi-zone support enabled
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- An existing `StatefulSet` using **Persistent Volumes** in a single-zone cluster.
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- [kubectl](/kubernetes/how-to/connect-cluster-kubectl/) installed and configured to interact with your Kubernetes cluster
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- [Scaleway CLI](/scaleway-cli/quickstart/) installed and configured
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- Familiarity with Kubernetes Persistent Volumes, `StatefulSets`, and Storage Classes.
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<Message type="important">
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**Backing up your data is crucial before making any changes.**
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Ensure you have a backup strategy in place. You can use tools like Velero for Kubernetes backups or manually copy data to another storage solution. Always verify the integrity of your backups before proceeding.
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</Message>
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## Identify existing Persistent Volumes
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1. Use `kubectl` to interact with your cluster and list the Persistent Volumes in your cluster:
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```sh
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kubectl get pv
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```
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2. Identify the volumes attached to your StatefulSet and note their `PersistentVolumeClaim` (PVC) names and `StorageClass`.
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Example output:
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```plaintext
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NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS ZONE
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pvc-123abc 10Gi RWO Retain Bound default/my-app-pvc scw-bssd fr-par-1
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```
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To find the `VOLUME_ID`, correlate this with the scw command output:
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```
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scw instance volume list
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```
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## Create snapshots of your existing Persistent Volumes
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Use the Scaleway CLI to create snapshots of your volumes.
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1. Retrieve the volume ID associated with the Persistent Volume:
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```sh
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scw instance volume list
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```
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2. Create a snapshot for each volume:
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```sh
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scw instance snapshot create volume-id=<VOLUME_ID> name=my-app-snapshot
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```
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3. Verify snapshot creation:
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```sh
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scw instance snapshot list
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```
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## Create multi-zone Persistent Volumes
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Once the snapshots are available, create new volumes in different zones:
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```sh
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scw instance volume create name=my-app-volume-new size=10GB type=bssd snapshot-id=<SNAPSHOT_ID> zone=fr-par-2
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```
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Repeat this for each zone required.
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<Meessage type="tip">
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Choose zones based on your distribution strategy. Check Scaleway's [zone availability](/account/reference-content/products-availability/) for optimal placement.
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</Message>
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## Update Persistent Volume Claims (PVCs)
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<Message type="important">
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Deleting a PVC can lead to data loss if not managed correctly. Ensure your application is scaled down or data is backed up.
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</Message>
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Modify your `PersistentVolumeClaims` to reference the newly created volumes.
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1. Delete the existing PVC (PVCs are immutable and cannot be updated directly):
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```sh
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kubectl delete pvc my-app-pvc
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```
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2. Create a new PVC with a multi-zone compatible `StorageClass`:
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```yaml
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apiVersion: v1
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kind: PersistentVolumeClaim
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metadata:
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name: my-app-pvc
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spec:
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accessModes:
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- ReadWriteOnce
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storageClassName: "scw-bssd-multi-zone"
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resources:
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requests:
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storage: 10Gi
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```
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3. Apply the updated PVCs:
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```sh
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kubectl apply -f my-app-pvc.yaml
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```
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## Reconfigure the StatefulSet to use multi-zone volumes
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1. Edit the `StatefulSet` definition to use the newly created Persistent Volume Claims.
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Example `StatefulSet` configuration:
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```yaml
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apiVersion: apps/v1
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kind: StatefulSet
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metadata:
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name: my-app
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spec:
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volumeClaimTemplates:
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- metadata:
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name: my-app-pvc
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spec:
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storageClassName: "scw-bssd-multi-zone"
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accessModes:
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- ReadWriteOnce
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resources:
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requests:
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storage: 10Gi
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```
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2. Apply the `StatefulSet` changes:
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```sh
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kubectl apply -f my-app-statefulset.yaml
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```
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## Verify migration
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1. Check that the `StatefulSet` pods are running in multiple zones:
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```sh
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kubectl get pods -o wide
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```
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2. Ensure that the new Persistent Volumes are bound and correctly distributed across the zones:
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```sh
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kubectl get pv
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```
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## Considerations for volume expansion
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If you need to **resize the Persistent Volume**, ensure that the `StorageClass` supports volume expansion.
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1. Check if the feature is enabled:
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```sh
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kubectl get storageclass scw-bssd-multi-zone -o yaml | grep allowVolumeExpansion
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```
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2. If `allowVolumeExpansion: true` is present, you can modify your PVC:
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```yaml
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spec:
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resources:
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requests:
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storage: 20Gi
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```
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3. Then apply the change:
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```sh
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kubectl apply -f my-app-pvc.yaml
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```
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## Conclusion
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You have successfully migrated your Persistent Volumes to a multi-zone Kapsule setup. Your `StatefulSet` is now distributed across multiple zones, improving resilience and availability.
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For further optimization, consider implementing [Pod anti-affinity](https://kubernetes.io/docs/concepts/scheduling-eviction/assign-pod-node/#affinity-and-anti-affinity) rules to ensure an even distribution of workloads across zones.
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