nova-manage cellv2 create_cell might create a duplicate cell1

[Adrien Cunin]

The "Perform cell_v2 initial cell setup" task runs "nova-manage cell_v2 create_cell" with endpoints for the DB and RabbitMQ. This is idempotent on the Nova side as long as you give exactly the same endpoints. If you don't, then Nova creates a new, almost identical, cell.

Experienced this issue when adding a RabbitMQ node to the cluster, I ended up with two "cell1". This confuses Nova a little bit... "openstack compute service list" returns every service twice, resource usage reports are incorrect by a factor of two, etc.

Because (as far as I know) OSA can handle only one cell anyway currently, it should *update* the existing cell if there is one, instead of creating it.

Similar bug in TripleO: https://bugs.launchpad.net/tripleo/+bug/1718912

[Jean-Philippe Evrard (jean-philippe-evrard)]

It looks reasonable to me to update if they have the same name by default, but I'd like others to step in too.

[Jesse Pretorius (jesse-pretorius)]

The fix for this will need to be ported back all the way to Ocata.

[Adrien Cunin (adri2000)]

Not sure how we're going to fix that properly, because to use `nova-manage cell_v2 update_cell` we need the cell_uuid, and looks like the only way to get it is to parse the tabular output of `nova-manage cell_v2 list_cells`...

[Dmitriy Rabotyagov (noonedeadpunk)]

I believe that this bug has been covered with https://review.opendev.org/c/openstack/openstack-ansible-os_nova/+/786258

Can you kindly check that and confirm?

[Dmitriy Rabotyagov (noonedeadpunk)]

There's also a related bug report to nova team https://bugs.launchpad.net/nova/+bug/1923899

[Sylvain Bauza (sylvain-bauza)]

Sounds a legit bug in Nova.
We only verify the existing transport url and database connections as being unique for a cell here : https://github.com/openstack/nova/blob/c4cd6ee4615a35a57dd6a2f3cb5a9cbc8653f7ee/nova/cmd/manage.py#L662-L675

That being said, we don't verify that the name is not unique here https://github.com/openstack/nova/blob/master/nova/cmd/manage.py#L1116 as there is no UniqueConstraint in the DB on the name field https://github.com/openstack/nova/blob/c4cd6ee4615a35a57dd6a2f3cb5a9cbc8653f7ee/nova/db/api/models.py#L141

Putting it as Triaged then, as I think two cells having the same name (using different transport URLs) could be an issue for the operator.

[Dmitriy Rabotyagov (noonedeadpunk)]

@sylvain-bauza I'd likely marked this one as duplicate of #1923899 in nova at least. I just didn't know other way to link bugs then add it another project...

Or you can close 2 in one shot :)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/nova/+/876940