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Rollback ​

When a deployment introduces bugs or breaks functionality, Norn provides rollback capabilities to quickly revert to a previous version.

How Rollback Works ​

Norn's rollback mechanism finds the second most recent deployment and updates the Kubernetes deployment to use that version's image. This is a fast operation that only modifies the image tag, without rebuilding or running migrations.

CLI Rollback ​

Roll back an application to its previous version:

bash
norn rollback myapp

This automatically finds the last known-good deployment and switches to it.

API Rollback ​

You can also trigger rollback via the API:

bash
POST /api/apps/:id/rollback

Specifying a Version ​

To roll back to a specific version instead of the previous one:

bash
POST /api/apps/:id/rollback
{
  "imageTag": "myapp:abc123"
}

If imageTag is not specified, Norn uses the previous deployment's image automatically.

Snapshot Restore ​

Rollback only reverts the application code, not the database. If a migration in the new version caused issues, you may need to manually restore the database from a snapshot.

Restore Process ​

  1. Locate the snapshot file in the snapshots/ directory:

    snapshots/<db>_<sha>_<timestamp>.dump

  2. Restore using pg_restore:

    bash
    pg_restore -d <database> snapshots/<db>_<sha>_<timestamp>.dump

  3. Verify the restored data is correct before resuming normal operations.

Artifact Retention ​

Norn automatically manages snapshot and artifact retention based on your infraspec configuration:

yaml
artifacts:
  retain: 5  # Keep last 5 versions (default)

Older snapshots are automatically cleaned up to prevent disk space exhaustion. Adjust this value based on your rollback needs and available storage.

When Rollback Isn't Enough ​

Rollback is designed for quick recovery from bad deployments. However, it may not be sufficient if:

  • Database migrations are irreversible: Some schema changes (like dropping columns) can't be undone by simply restoring a snapshot
  • External dependencies changed: If the new version modified external APIs or services, rolling back code alone won't fix integration issues
  • Data corruption occurred: Rollback won't fix data that was corrupted by the bad version while it was running

In these cases, you may need manual intervention to fully recover.