Comment 3 for bug 1665449

I can confirm the problem:

rabbitmqctl list_queues -p openstack | grep notifications.info
notifications.info 0
versioned_notifications.info 62

I think that for a given deployment this can be configured to a certain extent via "topics" option in oslo.messaging, however, there are caveats.

https://github.com/openstack/oslo.messaging/blob/stable/pike/oslo_messaging/notify/notifier.py#L48-L55

https://github.com/openstack/ceilometer/blame/stable/pike/doc/source/contributor/install/custom.rst#L39-L60
"By default, the ceilometer.conf file is as follows::
   [oslo_messaging_notifications]
   topics = notifications"

Also, it is possible to control which types of notifications are emitted on the nova side (unversioned, versioned, both):

https://github.com/openstack/nova/blob/stable/pike/nova/conf/notifications.py#L88-L105

event_definitions.yaml on the ceilometer side will need to be written to properly handle versioned events as they seem to have different field names:

https://github.com/openstack/ceilometer/blob/stable/pike/ceilometer/pipeline/data/event_definitions.yaml