Use a configuration update to change desired behavior. Use restart to replace running tasks without inventing a configuration change.
Update
Open application settings, make the intended change, and save. Changes to images, environment, resources, networking, or supported configuration files may cause task replacement. Review the update strategy and any Guardian validation before a release.
Saving identical settings is a no-op and does not force new containers. A registry tag changing outside CDelivery also does not automatically schedule an update.
Restart
Use the application’s restart action when tasks need replacement. Restart follows the application’s update strategy; it does not guarantee uninterrupted service. The default stop-first, all-at-once strategy can interrupt all replicas.
Restarting does not delete a correctly mounted volume, reset database contents, or solve an invalid command. If the process immediately fails again, inspect logs and fix its cause.
Verify
Compare desired and actual replicas, inspect the image and startup logs, check relevant events, and issue a business request. For a stateful application, verify data as well.
An accepted request may precede completed replacement. Do not submit repeated updates just because the first replacement is still progressing.
Rollback and removal
When a previous configuration is available, rollback can restore it. It does not undo migrations or restore files. Deleting an application is separate and retains its data volumes.