Restore Data from Azure Blob Storage Using BR

This document describes how to restore the backup data stored in Azure Blob Storage to a TiDB cluster on Kubernetes, including two restoration methods:

Full restoration. This method takes the backup data of snapshot backup and restores a TiDB cluster to the time point of the snapshot backup.
Point-in-time recovery (PITR). This method takes the backup data of both snapshot backup and log backup and restores a TiDB cluster to any point in time.

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.

PITR allows you to restore a new TiDB cluster to any point in time of the backup cluster. To use PITR, you need the backup data of snapshot backup and log backup. During the restoration, the snapshot backup data is first restored to the TiDB cluster, and then the log backup data between the snapshot backup time point and the specified point in time is restored to the TiDB cluster.

Note

BR is only applicable to TiDB v3.1 or later releases.
PITR is only applicable to TiDB v6.3 or later releases.
Data restored by BR cannot be replicated to a downstream cluster, because BR directly imports SST and LOG files to TiDB and the downstream cluster currently cannot access the upstream SST and LOG files.

Full restoration

This section 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.

Prerequisites: Complete the snapshot backup

In this example, the my-full-backup-folder folder in the my-container bucket of Azure Blob Storage stores the snapshot backup data. For steps of performing snapshot backup, refer to Back up Data to Azure Blob Storage Using BR.

Step 1: Prepare the restoration environment

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

Create a namespace for managing restoration. The following example creates a restore-test namespace:
```
kubectl create namespace restore-test
```
Download backup-rbac.yaml, and execute the following command to create the role-based access control (RBAC) resources in the restore-test namespace:
```
kubectl apply -f backup-rbac.yaml -n restore-test
```
Grant permissions to the remote storage for the restore-test namespace. You can grant permissions to Azure Blob Storage by two methods. For details, refer to Azure account permissions. After you grant the permissions, the restore-test namespace has a secret object named azblob-secret or azblob-secret-ad.
Note
The role owned by the account must have the permission to modify blob at least (for example, a contributor).
When you create a secret object, you can use a customized name for the object. In this document, the name is azblob-secret.
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

Create a Restore CR named demo2-restore-azblob in the restore-test namespace to restore cluster data as described below:

kubectl apply -f restore-full-azblob.yaml

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

---
apiVersion: pingcap.com/v1alpha1
kind: Restore
metadata:
  name: demo2-restore-azblob
  namespace: test2
spec:
  # prune: afterFailed
  br:
    cluster: demo2
    clusterNamespace: test2
    # logLevel: info
    # statusAddr: ${status_addr}
    # concurrency: 4
    # rateLimit: 0
    # timeAgo: ${time}
    # checksum: true
    # sendCredToTikv: true
  azblob:
    secretName: azblob-secret
    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.
spec.azblob.secretName: fill in the name of the secret object, such as azblob-secret.
For v4.0.8 or a later version, BR can automatically adjust tikv_gc_life_time. You do not need to configure the spec.to fields in the Restore CR.
For more information about the Restore CR fields, refer to Restore CR fields.
For TiDB v9.0.0 and later versions, the Restore CR supports a new field .spec.prune, which can be set to afterFailed to clean up residual metadata tables after a failed restore. Enabling this field changes the behavior and status of the Restore CR when it enters the Failed state. This feature is not supported in versions earlier than v9.0.0. For more details about the .spec.prune field, see Prune field.

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

kubectl get restore -n restore-test -o wide

NAME                   STATUS     ...
demo2-restore-azblob   Complete   ...

If you set .spec.prune to afterFailed, you might see the following restore status:

kubectl get restore -n restore-test -o wide

NAME               STATUS     ...
demo3-restore-s3   PruneComplete   ...

Point-in-time recovery

This section provides an example about how to perform point-in-time recovery (PITR) in a demo3 cluster in the test3 namespace. PITR takes two steps:

Restore the cluster to the time point of the snapshot backup using the snapshot backup data in the spec.pitrFullBackupStorageProvider.azblob.prefix folder of the spec.pitrFullBackupStorageProvider.azblob.container bucket.
Restore the cluster to any point in time using the log backup data in the spec.azblob.prefix folder of the spec.azblob.container bucket.

The detailed steps are as follows.

Prerequisites: Complete data backup

In this example, the my-container bucket of Azure Blob Storage stores the following two types of backup data:

The snapshot backup data generated during the log backup, stored in the my-full-backup-folder-pitr folder.
The log backup data, stored in the my-log-backup-folder-pitr folder.

For detailed steps of how to perform data backup, refer to Back up data to Azure Blob Storage.

Note

The specified restoration time point must be between the snapshot backup time point and the log backup checkpoint-ts.

Step 1: Prepare the restoration environment

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

Create a namespace for managing restoration. The following example creates a restore-test namespace:
```
kubectl create namespace restore-test
```
Download backup-rbac.yaml, and execute the following command to create the role-based access control (RBAC) resources in the restore-test namespace:
```
kubectl apply -f backup-rbac.yaml -n restore-test
```
Grant permissions to the remote storage for the restore-test namespace. You can grant permissions to Azure Blob Storage by two methods. For details, refer to Azure account permissions. After you grant the permissions, the restore-test namespace has a secret object named azblob-secret or azblob-secret-ad.
Note
The role owned by the account must have the permission to access blob at least (for example, a reader).
When you create a secret object, you can use a customized name for the object. In this document, the name is azblob-secret.

Step 2: Restore the backup data to a TiDB cluster

The example in this section restores the snapshot backup data to the cluster. The specified restoration time point must be between the time point of snapshot backup and the Log Checkpoint Ts of log backup.

The detailed steps are as follows:

Create a Restore CR named demo3-restore-azblob in the restore-test namespace and specify the restoration time point as 2022-10-10T17:21:00+08:00:

kubectl apply -f restore-point-azblob.yaml

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

---
apiVersion: pingcap.com/v1alpha1
kind: Restore
metadata:
  name: demo3-restore-azblob
  namespace: restore-test
spec:
  restoreMode: pitr
  # prune: afterFailed
  br:
    cluster: demo3
    clusterNamespace: test3
  azblob:
    secretName: azblob-secret
    container: my-container
    prefix: my-log-backup-folder-pitr
  pitrRestoredTs: "2022-10-10T17:21:00+08:00"
  pitrFullBackupStorageProvider:
    azblob:
      secretName: azblob-secret
      container: my-container
      prefix: my-full-backup-folder-pitr

When you configure restore-point-azblob.yaml, note the following:

spec.restoreMode: when you perform PITR, set this field to pitr. The default value of this field is snapshot, which means snapshot backup.

Wait for the restoration operation to complete:

kubectl get jobs -n restore-test

NAME                           COMPLETIONS   ...
restore-demo3-restore-azblob   1/1           ...

You can also check the restoration status by using the following command:

kubectl get restore -n restore-test -o wide

NAME                   STATUS     ...
demo3-restore-azblob   Complete   ...

If you set .spec.prune to afterFailed, you might see the following restore status:

kubectl get restore -n restore-test -o wide

NAME               STATUS     ...
demo3-restore-s3   PruneComplete   ...

Troubleshooting

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

Restore Data from Azure Blob Storage Using BR

Full restoration

Prerequisites: Complete the snapshot backup

Step 1: Prepare the restoration environment

Step 2: Restore the backup data to a TiDB cluster

Point-in-time recovery

Prerequisites: Complete data backup

Step 1: Prepare the restoration environment

Step 2: Restore the backup data to a TiDB cluster

Troubleshooting

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