Container Service for Kubernetes:Migrate applications across clusters in different regions

Usage notes

• Cross-region migration supports application backup. You can also use cross-region migration to back up volumes that use Alibaba Cloud disks.

  If you use an ACK dedicated cluster or registered cluster that connects to a self-managed Kubernetes cluster consisting of Elastic Compute Service (ECS) nodes, you need to check whether the ECS Snapshot permissions are granted to the cluster before you can migrate applications across clusters in different regions. For more information, see Install migrate-controller and grant permissions.

• When the backup center backs up applications, the resources that are being deleted are not backed up.

Preparations

The example in this topic shows how to back up and restore applications across clusters in different regions. In this example, an ACK Pro cluster named Cluster_BJ is created in the China (Beijing) region and used as the source cluster to back up applications. An ACK Pro cluster named Cluster_SZ is created in the China (Shenzhen) region and used as the destination cluster to restore applications. A backup vault is associated with an Object Storage Service (OSS) bucket in the China (Beijing) region.

1. Create an OSS bucket named cnfs-oss-*** in the China (Beijing) region.

   Skip this step if an OSS bucket that meets the requirement is already created in the region.

2. Run the following command to create a stateful NGINX application in the default namespace of the Cluster_BJ cluster.

   YAML file of the stateful Nginx application

   cat << EOF | kubectl apply -f -
   apiVersion: apps/v1
   kind: StatefulSet
   metadata:
     name: web
   spec:
     selector:
       matchLabels:
         app: nginx
     serviceName: "nginx"
     replicas: 1
     template:
       metadata:
         labels:
           app: nginx
       spec:
         containers:
           - name: nginx
             image: nginx:1.14.2
             ports:
               - containerPort: 80
                 name: web
             volumeMounts:
               - name: www
                 mountPath: /usr/share/nginx/html
     volumeClaimTemplates:
       - metadata:
           name: www
           labels:
             app: nginx
         spec:
           accessModes: [ "ReadWriteOnce" ]
           storageClassName: "alicloud-disk-topology-alltype"
           resources:
             requests:
               storage: 20Gi
   EOF

Step 1: Create a backup vault

When you back up applications in an ACK cluster, the backup files are stored in an OSS bucket. If no backup vault is available when you create a backup plan, you must perform the operations in Step 1. For more information about how to create a backup vault, see Create a backup vault.

Step 2: Create a backup plan in the Cluster_BJ cluster

For more information about how to create a backup plan, see Create a backup plan or back up instantly.

Step 3: Restore applications to the Cluster_SZ cluster

For more information about how to restore applications, see Step 3: Restore applications and volumes.

Step 4: Check whether the NGINX application is migrated

1. Log on to the ACK console. In the left-side navigation pane, click Clusters.

2. In the left-side navigation pane of the Cluster_SZ cluster management page, choose Workloads > Deployments.

3. Click Details in the Actions column of the NGINX application. Then, click the Pods tab.

   If the status of the pods is Running, the NGINX application is migrated.

References

• For more information about how to migrate applications across clusters that use different volume plug-ins or run different Kubernetes versions, see Use the backup center to migrate applications in an ACK cluster that runs an old Kubernetes version.

• For more information about how to use the CLI to migrate applications, see Use kubectl to back up and restore applications.