Backing Up HDFS NameNode Data

Scenarios

To ensure NameNode service data security routinely or before a major operation on NameNode (such as upgrade or migration), you need to back up NameNode data. The backup data can be used to recover the system if an exception occurs or the operation has not achieved the expected result, minimizing the adverse impacts on services.

NameNode metadata backup tasks can be created on FusionInsight Manager. The system supports both automatic and manual backup modes.

MRS clusters support multiple data path types for backing up NameNode metadata.

• LocalDir: indicates that backup files are stored on the local disk of the active management node, with the standby management node automatically synchronizing the backup files.

  The default storage directory is Data storage path/LocalBackup/, for example, /srv/BigData/LocalBackup.

• RemoteHDFS: indicates that backup files are stored in the HDFS directory of the standby cluster.
• NFS: indicates that backup files are stored in NAS using the NFS protocol.
• CIFS: indicates that backup files are stored in NAS using the CIFS protocol.
• SFTP: indicates that backup files are stored in the server using the SFTP protocol.
• OBS: indicates that backup files are stored in OBS.

Notes and Constraints

MRS 3.1.0 and later versions support the backup of NameNode metadata to OBS.

Prerequisites

• To back up data to a remote HDFS, the following conditions must be met:
  • A standby cluster for backing up data has been created. Its authentication mode must be the same as that of the active cluster.
  • If the active cluster is deployed in security mode and the active and standby clusters are not managed by the same FusionInsight Manager, mutual trust has been configured. For details, see Configuring Mutual Trust Between MRS Clusters. If the active cluster is deployed in normal mode, mutual trust is not required.
  • Cross-cluster replication has been configured for the active and standby clusters. For details, see Enabling MRS Inter-Cluster Replication.
  • Time is consistent between the active and standby clusters, with the NTP services on both clusters configured to use the same time source.
• The backup type, period, policy, and other specifications have been planned based on the service requirements and you have checked whether Data storage path/LocalBackup/ has sufficient space on the active and standby management nodes.

• If you want to back up data to NAS, you have deployed the NAS server in advance.
• If you want to back up data to OBS, you have connected the current cluster to OBS and have the permission to access OBS.

Backing Up HDFS NameNode Data

1. Log in to MRS Manager.

   For details about how to log in to MRS Manager, see Accessing MRS Manager.

2. Choose O&M > Backup and Restoration > Backup Management.
3. Click Create.
4. Set Name to the name of the backup task.
5. Select the cluster to be operated from Backup Object.
6. Set Mode to the type of the backup task.

   Periodic indicates that the backup task is executed by the system periodically. Manual indicates that the backup task is executed manually.

   Table 1 Periodic backup parameters

   Parameter	Example Value	Description
   Started	2024/11/22 10:29:11	Time when the task should start for the first time.
   Period	1 day	Task execution interval. Supported values are Hours and Days.
   Backup Policy	Full backup every time	Only Full backup every time is supported. Incremental backup is not supported for Manager data and component metadata. Only Full backup every time is supported. If Path Type is set to NFS or CIFS, incremental backup cannot be used. When incremental backup is used for NFS or CIFS backup, the latest full backup data is updated each time the incremental backup is performed. Therefore, no new recovery point is generated.

7. In Configuration, select NameNode.
8. Select a backup directory type for Path Type of NameNode.

   Table 2 Path of backup data

   Path Type	Parameter	Description
   LocalDir	Maximum Number of Backup Copies	Number of backup files that can be retained in the backup directory.
   	NameService Name	NameService name of the backup directory. The default value is hacluster.
   RemoteHDFS	Destination NameService Name	Name of the NameService in the standby cluster. You can set it to the NameService name (haclusterX, haclusterX1, haclusterX2, haclusterX3, or haclusterX4) of the built-in remote cluster. You can also set it to the NameService name of a configured remote cluster.
   	IP Mode	IP version of the target IP address. The system automatically determines the IP version, such as IPv4 or IPv6, based on the cluster network type.
   	Target NameNode IP Address	Service plane IP address of the NameNode in the standby cluster.
   	Target Path	Path for storing backup files.
   	Maximum Number of Backup Copies	Number of backup files that can be retained in the backup directory.
   	NameService Name	NameService name of the backup directory. The default value is hacluster.
   	Queue Name	Name of the YARN queue used for backup task execution. The name must be identical to that of a queue currently running properly in the cluster.
   NFS	IP Mode	IP version of the target IP address. The system automatically determines the IP version, such as IPv4 or IPv6, based on the cluster network type.
   	Server IP Address	IP address of the NAS server.
   	Server Shared Path	Shared directory configured on the NAS server by the user. The shared directory of the server cannot be set to the root directory. The user group and owner group of the shared directory must be configured as nobody:nobody.
   	Maximum Number of Backup Copies	Number of backup files that can be retained in the backup directory.
   	NameService Name	NameService name of the backup directory. The default value is hacluster.
   CIFS	IP Mode	IP version of the target IP address. The system automatically determines the IP version, such as IPv4 or IPv6, based on the cluster network type.
   	Server IP Address	IP address of the NAS server.
   	Port	Port number used by the CIFS protocol to connect to the NAS server. The default value is 445.
   	Username	Username configured during CIFS protocol setup.
   	Password	Password configured during CIFS protocol setup.
   	Server Shared Path	Shared directory configured on the NAS server by the user. The shared directory of the server cannot be set to the root directory. The user group and owner group of the shared directory must be configured as nobody:nobody.
   	Maximum Number of Backup Copies	Number of backup files that can be retained in the backup directory.
   	NameService Name	NameService name of the backup directory. The default value is hacluster.
   SFTP	IP Mode	IP version of the target IP address. The system automatically determines the IP version, such as IPv4 or IPv6, based on the cluster network type.
   	Server IP Address	IP address of the server where the backup data is stored.
   	Port	Port number used by the SFTP protocol to connect to the backup server. The default value is 22.
   	Username	Username used to connect to the server over SFTP.
   	Password	Password used to connect to the server over SFTP.
   	Server Shared Path	Backup path on the SFTP server.
   	Maximum Number of Backup Copies	Number of backup files that can be retained in the backup directory.
   	NameService Name	NameService name of the backup directory. The default value is hacluster.
   OBS	Target Path	OBS directory for storing backup data.
   	Maximum Number of Backup Copies	Number of backup files that can be retained in the backup directory.
   	NameService Name	NameService name of the backup directory. The default value is hacluster.

9. Click OK.
10. In the Operation column of the created task in the backup task list, click More and select Back Up Now to execute the backup task.

    After the backup task is executed, the system automatically creates a subdirectory for each backup task in the backup directory. The format of the subdirectory name is Backup task name_Task creation time, and the subdirectory is used to save data source backup files. The format of the backup file name is Version_Data source_Task execution time.tar.gz.

Helpful Links

Backup HDFS NameNode metadata may be restored if data is accidentally modified, deleted, or requires retrieval; if major NameNode operations (such as upgrades or significant data adjustments) cause exceptions in system data or fail to achieve the expected result; if all modules fail and become unavailable; or if data needs to be migrated to a new cluster. For detailed operations, refer to Restoring HDFS NameNode Metadata.