Comment 13 for bug 1993149

I was able to recreate this as well on jammy-yoga. A few findings:

* transport_url is in the DEFAULT section as well as the oslo_messaging_notifications section for nova.conf, though I don't think this is a problem

* the cell_mappings table in the nova_api database contains the same transport url for cell1 as expected (note this doesn't get updated when a rabbit node goes down, probably as expected)

* relation_settings['ha_queues'] never gets set to True anymore in charm-rabbitmq-server for versions >= 3.0.1 [1]. This results in rabbit_ha_queues never getting set to True in clients such as nova [2]. This doesn't solve the problem but may also be required in order to properly mirror queues for failover.

[1] https://opendev.org/openstack/charm-rabbitmq-server/src/branch/master/hooks/rabbitmq_server_relations.py#L485

[2] https://opendev.org/openstack/charm-nova-cloud-controller/src/branch/master/charmhelpers/contrib/openstack/context.py#L703

* kombu_failover_strategy should be defaulting to round-robin according to [3]. I think this is the next place to dig into.

[3] https://docs.openstack.org/oslo.messaging/latest/configuration/opts.html#oslo_messaging_rabbit.kombu_failover_strategy