Code review comment for lp:~jk0/nova/diagnostics-per-instance

Discussion from irc:

jk0: it's for this BP: https://blueprints.launchpad.net/nova/+spec/diagnostics-per-instance
[10:13am] vishy: jk0: this ultimately needs to be a message passed back from compute
[10:14am] vishy: jk0: I'm not convinced that we want that stuff in a database long term
[10:14am] vishy: jk0: but i suppose it can go in there initially
[10:15am] jk0: I'd have to rethink how we'd do that
[10:16am] vishy: jk0: eday is working on that piece for the distributed data model
[10:16am] jk0: do you think we should hold off on this until that is in place?
[10:17am] jk0: or would it make sense to keep going and refactor later on
[10:17am] vishy: jk0: just make sure that it is easy to pass the relevant data as a message, since we're trying to stop computes from writing directly to the database.

I think moving ahead with this is fine for now as long as we have a clear way to pass the updates through the queue so that ultimately the computes are not writing directly to the db.