How to backup and restore SQL databases in container orchestration platforms (e.g. Kubernetes)

20 Sep 2023

In container orchestration platforms like Kubernetes, running SQL databases in containers offers flexibility in scaling and managing databases. However, it is essential to ensure data durability and implement backup and restore strategies to safeguard against data loss or corruption.

Backup Strategies

1. StatefulSets

If you are using StatefulSets to deploy your SQL database in Kubernetes, you can leverage the built-in snapshot feature. StatefulSets offer stable network identities and persistent storage, making it easier to handle backups.

To backup your SQL database running in a StatefulSet:

Connect to the database: Use the appropriate client tool (e.g., kubectl exec) to connect to the SQL database instance.
Perform a database dump: Use the appropriate commands (e.g., mysqldump for MySQL) to create a database dump. Specify the output file location within the container or write it to a shared volume.
Copy the backup file: Copy the backup file from the container to a backup location, using commands like kubectl cp or mounting a shared volume to access the backup file.
Store the backup: Store the backup file in a durable storage solution such as object storage (e.g., AWS S3) or a network file system (NFS) accessible to the Kubernetes cluster.

2. Persistent Volumes

If you are not using StatefulSets but have persistent volumes attached to your SQL database containers, you can use the following method to backup your data:

Create volume snapshots: Utilize the snapshot functionality provided by the underlying storage provider (e.g., CSI, Rook) to create a point-in-time snapshot of the persistent volume.
Export snapshots: Export the volume snapshots to a backup location outside the Kubernetes cluster, ensuring the durability and availability of the backup data.

Restore Strategies

1. StatefulSets

To restore a SQL database running in a StatefulSet:

Prepare the backup data: Ensure the backup files are accessible either locally or in a storage solution.
Copy the backup files: Use commands like kubectl cp or mount shared volumes to copy the backup files into the container running the SQL database.
Restore the database: Execute the appropriate database restore command (e.g., mysql for MySQL) to import the backup data into the running database instance.

2. Persistent Volumes

To restore a SQL database using persistent volumes:

Import the snapshots: Import the previously exported volume snapshots back into the Kubernetes cluster using the storage provider’s import capability.
Mount the restored volumes: Update your deployment configuration to mount the restored volumes to the SQL database containers.
Start the database: Restart the SQL database container(s) to start using the restored data.

Conclusion

In container orchestration platforms like Kubernetes, backing up and restoring SQL databases requires careful consideration of the underlying infrastructure and storage options. Whether using StatefulSets or persistent volumes, implementing a robust backup and restore strategy ensures data durability and minimizes the risk of data loss in case of failures.

#SQL #BackupAndRestore #ContainerOrchestration