Restore Data from Azure Blob Storage Using BR

This document describes how to restore the backup SST files stored in Azure Blob Storage to a TiDB cluster on Kubernetes.

The restore method described in this document is implemented based on CustomResourceDefinition (CRD) in TiDB Operator. For the underlying implementation, BR is used to restore the data. BR stands for Backup & Restore, which is a command-line tool for distributed backup and recovery of the TiDB cluster data.

Usage Scenarios

After backing up TiDB cluster data to Azure Blob Storage using BR, if you need to restore the backup SST (key-value pairs) files from Azure Blob Storage to a TiDB cluster, you can follow the steps in this document to restore the data using BR.

This document provides an example about how to restore the backup data from the spec.azblob.prefix folder of the spec.azblob.container bucket on Azure Blob Storage to the demo2 TiDB cluster in the test2 namespace. The following are the detailed steps.

Step 1. Prepare the restore environment

Before restoring backup data on Azure Blob Storage to TiDB using BR, take the following steps to prepare the restore environment:

1. Download backup-rbac.yaml, and execute the following command to create the role-based access control (RBAC) resources in the test2 namespace:

   kubectl apply -f backup-rbac.yaml -n test2
   

2. Grant permissions to the remote storage. You can grant permissions to Azure Blob Storage by two methods. For details, refer to Azure account permissions.

3. For a TiDB version earlier than v4.0.8, you also need to complete the following preparation steps. For TiDB v4.0.8 or a later version, skip these preparation steps.

   1. Make sure that you have the SELECT and UPDATE privileges on the mysql.tidb table of the target database so that the Restore CR can adjust the GC time before and after the restore.

   2. Create the restore-demo2-tidb-secret secret to store the account and password to access the TiDB cluster:

      kubectl create secret generic restore-demo2-tidb-secret --from-literal=password=${password} --namespace=test2
      

Step 2. Restore the backup data to a TiDB cluster

Depending on which method you choose to grant permissions to the remote storage when preparing the restore environment, you can restore the data by doing one of the following:

• Method 1: If you grant permissions by access key, create the Restore CR to restore cluster data as described below:

  kubectl apply -f resotre-azblob.yaml
  

  The content of restore-azblob.yaml is as follows:

  ---
  apiVersion: pingcap.com/v1alpha1
  kind: Restore
  metadata:
    name: demo2-restore-azblob
    namespace: test2
  spec:
    br:
      cluster: demo2
      clusterNamespace: test2
      # logLevel: info
      # statusAddr: ${status_addr}
      # concurrency: 4
      # rateLimit: 0
      # timeAgo: ${time}
      # checksum: true
      # sendCredToTikv: true
    # # Only needed for TiDB Operator < v1.1.10 or TiDB < v4.0.8
    # to:
    #   host: ${tidb_host}
    #   port: ${tidb_port}
    #   user: ${tidb_user}
    #   secretName: restore-demo2-tidb-secret
    azblob:
      secretName: azblob-secret
      container: my-container
      prefix: my-folder
  

• Method 2: If you grant permissions by Azure AD, create the Restore CR to restore cluster data as described below:

  kubectl apply -f restore-azblob.yaml
  

  The content of restore-azblob.yaml is as follows:

  ---
  apiVersion: pingcap.com/v1alpha1
  kind: Restore
  metadata:
   name: demo2-restore-azblob
   namespace: test2
  spec:
   serviceAccount: tidb-backup-manager
   br:
     cluster: demo2
     sendCredToTikv: false
     clusterNamespace: test2
     # logLevel: info
     # statusAddr: ${status_addr}
     # concurrency: 4
     # rateLimit: 0
     # timeAgo: ${time}
     # checksum: true
   # Only needed for TiDB Operator < v1.1.10 or TiDB < v4.0.8
   to:
     host: ${tidb_host}
     port: ${tidb_port}
     user: ${tidb_user}
     secretName: restore-demo2-tidb-secret
   azblob:
     secretName: azblob-secret-ad
     container: my-container
     prefix: my-folder
  

When configuring restore-azblob.yaml, note the following:

• For more information about Azure Blob Storage configuration, refer to Azure Blob Storage fields.
• Some parameters in .spec.br are optional, such as logLevel, statusAddr, concurrency, rateLimit, checksum, timeAgo, and sendCredToTikv. For more information about BR configuration, refer to BR fields.
• For v4.0.8 or a later version, BR can automatically adjust tikv_gc_life_time. You do not need to configure spec.to fields in the Restore CR.
• For more information about the Restore CR fields, refer to Restore CR fields.

After creating the Restore CR, execute the following command to check the restore status:

kubectl get rt -n test2 -o wide

Troubleshooting

If you encounter any problem during the restore process, refer to Common Deployment Failures.