As part of enabling support for Cinder's asynchronous replication with the Ceph (RBD) backend in RHOSP, we need to ensure proper upstream test coverage and CI validation.

This story covers:

• Automating Tempest tests for Cinder's RBD replication feature in the upstream cinder-tempest-plugin.

• Ensuring both positive and negative test scenarios are implemented to validate replication behavior across failover and failback operations.

• Adding a Zuul gate job that runs the replication tests against a devstack deployment with Ceph (RBD) backend configured for replication.

• Making sure the job runs reliably and is gated on patches impacting Cinder replication logic.

The async replication feature is already implemented upstream but not previously supported in RHOSP. Adding test automation and CI validation is critical to ensure feature stability and compliance.

Acceptance Criteria

• All the tests should pass in the gates.
• The patches should be ready for review.