Description of problem: Starting with Mitaka Cells V2 is (apparently) at the point that deployments will be a cell of one. This carries with it some additional setup tasks, particularly creating the separate nova api database. We (nova) team need to document exactly what is required here and feed it into tripleo and as a result OSP-D. Version-Release number of selected component (if applicable): Red Hat OpenStack Platform 9/"Mitaka"
Relevant upstream docs patch: https://review.openstack.org/#/c/284803/
As part of this we need to confirm: (1) Is this absolutely mandatory to do in Mitaka. (2) What is the upgrade process for existing users, how does the new API DB get populated?
Looks like this may already be actioned in TripleO: https://review.openstack.org/#/c/276790/
I believe the only thing that will be required will be create, configure and sync the new database. If we don't land the flavor migration in Mitaka, then there won't really be any additional upgrade steps. All three steps can be done in Liberty before the upgrade, and then we just do the additional api_db sync alongside the normal db sync when we roll forward.