oslo messaging and notifications

novajoin needs to monitor nova notifications to know when an instance is deleted so the host can be removed from IPA as well. I originally coded it to use the notifications topic but ceilometer also uses this topic so novajoin-notify was getting only a subset of the deletes.

The fix is very easy, add a new topic to the topics option in nova.conf, e.g.

topics=notifications,novajoin

This isn’t at all obvious from any documentation.