How to Use ACK Backup Center for Volume Data Protection and Cross‑Cluster Migration

Introduction

In Kubernetes, a PersistentVolumeClaim (PVC) declares the underlying storage required by a container, and the Container Storage Interface (CSI) enables the application to mount the volume as if it were local storage. Application data is critical; loss or corruption can cause severe service disruption, so regular backups are essential for rapid recovery and for migrating data between environments.

ACK Backup Center Overview

ACK (Alibaba Cloud Container Service for Kubernetes) provides a Backup Center that offers a one‑stop disaster‑recovery and migration solution for containerized workloads. The Backup Center previously supported Application Backup, which captures full applications and their resources. In some scenarios only the storage volume and its data need to be backed up:

Existing CI/CD pipelines can redeploy applications via GitOps, making volume backup unnecessary.

Storage class conversion (e.g., NAS to Cloud Disk) can be achieved without backing up the entire application.

Point‑in‑time snapshots allow restoring data to a specific moment.

Data Protection Feature

The Data Protection feature treats a storage volume as the minimal backup unit. It supports one‑time or periodic backups, automatically packaging the PersistentVolume (PV), PersistentVolumeClaim (PVC), and the underlying data. During restore, the Backup Center recreates the PV and PVC with the original names, allowing applications to bind to the restored data without any code changes.

By default, Alibaba Cloud Cloud Disk snapshots are used for Cloud Disk volumes, while other volume types are backed up via Alibaba Cloud Backup Service. The system stores PVC and PV YAML files in Object Storage, adjusting them during restore to keep names consistent.

Backup Process

In the ACK console, navigate to Operations > Application Backup and complete the initial authorization, component installation, and backup repository creation.

Choose either Create Backup Plan for scheduled backups or Immediate Backup for a one‑off backup.

Select the target namespace (e.g., default).

When using Data Protection, pick one of three volume selection methods:

All volumes in the namespace.

Specific storage class.

Specific PVCs (by name).

Confirm the backup; the system creates a backup record showing type, source cluster, timestamp, and backup ID.

Example: NAS to Cloud Disk Migration

Two PVCs are defined, one using an Alibaba Cloud Disk storage class and the other using an Alibaba Cloud NAS storage class:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-disk
  namespace: default
spec:
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 20Gi
  storageClassName: alicloud-disk-topology-alltype
  volumeMode: Filesystem
  volumeName: d-2ze50bonvbinhjxxxxxx
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-nas
  namespace: default
spec:
  accessModes:
  - ReadWriteMany
  resources:
    requests:
      storage: 20Gi
  storageClassName: alibabacloud-cnfs-nas
  volumeMode: Filesystem
  volumeName: nas-4dxxxxxx-xxxx-xxxx-xxxx-4b1b4cxxxxxx

Using the Data Protection feature, a backup plan is created that selects both PVCs. After the backup finishes, the backup record shows two backup IDs: a Cloud Disk snapshot ID for pvc-disk and a Cloud Backup task ID for pvc-nas.

Restore Process

Switch to the target cluster, go to Operations > Application Backup , and click Immediate Restore . Select the backup repository (initialize it if it has not been linked to the cluster), choose the backup created earlier, and optionally enable the storage‑class conversion feature to change the volume type during restore (e.g., convert NAS to Cloud Disk).

After the restore task completes, the PVCs are recreated with their original names. If storage‑class conversion was enabled, the NAS PVC is recreated as a Cloud Disk PVC, demonstrating cross‑type migration.

The restored PVC for pvc-disk includes a dataSource pointing to the original VolumeSnapshot:

dataSource:
  apiGroup: snapshot.storage.k8s.io
  kind: VolumeSnapshot
  name: pvc-disk-volumesnapshot20250320xxxxxx

Because the alicloud-disk-topology-alltype storage class is of type WaitForFirstConsumer, the actual disk is provisioned only when the application first mounts it. After redeploying the stateful application via GitOps, the new Cloud Disk is created and the PVC reaches the Bound state.

Summary

Backup is a critical measure for data safety and business continuity, especially in container environments. Using ACK Backup Center’s Data Protection feature minimizes data‑loss risk and ensures stable operation by allowing granular volume backups, cross‑type migration, and seamless restore without modifying application code.