Recovering a cluster

If you have lost a ClickHouse® cluster in a project, you can recover it.

Using the CLIUsing the CLI

spec.clickhouse.recovery supports two recovery options:

• fullRecovery: Recovery of the whole cluster from one full backup. Specify the name of the ClickhouseBackup resource in spec.clickhouse.recovery.fullRecovery.backup.name. A good option if you have a full cluster backup.
• shardsRecovery: Recovery by shards from different backups. In spec.clickhouse.recovery.shardsRecovery.backups[], specify an element with the following fields for each shard:
  • backup.name: Name of the ClickhouseBackup resource for the shard.
  • shard: Shard ID (e.g., shard-1 or shard-2) must match shards[].id in the cluster specification.

List of backups: kubectl get ClickhouseBackup -n <project_name>.

1. Create the ClickhouseCluster resource file, Here is an example: touch clickhousecluster-from-backup.yaml.

2. Open the file and paste the configuration for recovery:

   From one full backup (fullRecovery)

   By shards (shardsRecovery)

   Substitute into spec.clickhouse.recovery.fullRecovery.backup.name the name of the backup to restore the whole cluster from.

   apiVersion: clickhouse.stackland.yandex.cloud/v1alpha1
   kind: ClickhouseCluster
   metadata:
     labels:
       app.kubernetes.io/name: ch-stackland-operator
       app.kubernetes.io/managed-by: kustomize
     name: ch-sample-full
   spec:
     clickhouse:
       version: "25.3"
       enableSuperuserAccess: true
       superuserSecretRef:
         name: "ch-sample-superuser"
       recovery:
         fullRecovery:
           backup:
             name: your_backup_full_name  # kubectl get ClickhouseBackup -n <namespace>
     backup:
       storage:
         type: stackland-storage
       schedule: "0 0 * * * *"
       deltaMaxSteps: 5
   ---
   apiVersion: v1
   kind: Secret
   metadata:
     name: ch-sample-superuser
   type: Opaque
   stringData:
     password: "your_password"
     username: "your_username"
   

   For each shard, specify in spec.clickhouse.recovery.shardsRecovery.backups[] an element with backup.name (name of backup for the shard) and shard (shard ID). The number of elements must match the number of shards in the cluster.

   apiVersion: clickhouse.stackland.yandex.cloud/v1alpha1
   kind: ClickhouseCluster
   metadata:
     labels:
       app.kubernetes.io/name: ch-stackland-operator
       app.kubernetes.io/managed-by: kustomize
     name: ch-sample-full
   spec:
     clickhouse:
       version: "25.3"
       shards:
         - id: "shard-1"
           weight: 1
           settings:
           instances: 2
           storage:
   #          storageClass: "your-storage-class"
             size: 2Gi
         - id: "shard-2"
           weight: 2
           settings:
           instances: 1
           storage:
   #          storageClass: "your-storage-class"
             size: 2Gi
       storage:
   #      storageClass: "your-storage-class"
         size: 2Gi
       resources:
         requests:
           cpu: "500m"
           memory: "1Gi"
         limits:
           cpu: "1"
           memory: "2Gi"
       enableSuperuserAccess: true
       superuserSecretRef:
         name: "ch-sample-superuser"
       recovery:
         shardsRecovery:
           backups:
             - backup:
                 name: your_backup_shard_1_name
               shard: "shard-1"
             - backup:
                 name: your_backup_shard_2_name
               shard: "shard-2"
     keeper:
       instances: 3
       storage:
   #      storageClass: "your-storage-class"
         size: 1Gi
       resources:
         requests:
           cpu: "500m"
           memory: "1Gi"
         limits:
           cpu: "1"
           memory: "2Gi"
     backup:
       storage:
         type: stackland-storage
       schedule: "0 0 * * * *"
   ---
   apiVersion: v1
   kind: Secret
   metadata:
     name: ch-sample-superuser
   type: Opaque
   stringData:
     password: "your_password"
     username: "your_username"
   

3. Apply the manifest: kubectl apply -f clickhousecluster-from-backup.yaml -n <project_name>. Optionally, you can specify the project name in the metadata.namespace resource property and skip it in the command.

Using the management consoleUsing the management console

1. If you have not opened a project yet, select one.
2. In the left-hand menu, select ClickHouse® Clusters.
3. Go to the Backups tab.
4. In the row with the backup you need, click Restore.
5. Check the cluster settings and modify them, if required:
6. Click Restore.

That is it! Your cluster has been recovered and now appears in the project's cluster list.