[openstack-dev] Quantum + ZeroMQ (with a sprinkling of Nova) in Folsom
eric at cloudscaling.com
Tue Sep 25 21:17:52 UTC 2012
Dan, great (well, kind of). I had thought it was merged into the Folsom branch.
On Tuesday, September 25, 2012 at 17:12 PM, Dan Wendlandt wrote:
> On Tue, Sep 25, 2012 at 1:45 PM, Mark McLoughlin <markmc at redhat.com (mailto:markmc at redhat.com)> wrote:
> > On Tue, 2012-09-25 at 13:28 -0400, Eric Windisch wrote:
> > > Russell, perhaps. The issue is that if the message format changes, it
> > > would be lower cost to do it now. Also, I'm moving this to the public
> > > list, because I agree that it is a good time to do it.
> > >
> > > IF there is an RC3 for Nova, I'd like for consideration to get the
> > > message-format change in, because it reduces complexity for Grizzly
> > > (having to understand two formats), and because it will make the
> > > Quantum code supportable. This binary needs to move outside of Nova to
> > > avoid this unnecessary interdependency.
> > >
> > > It might be resolvable by adding a version to the message format, but
> > > it doesn't solve the problem today - which, arguably, doesn't have to
> > > be solved. We can just release with the zeromq stuff broken in Quantum
> > > for Folsom, without any ability to backport, and I'm prepared for that
> > > to happen. I've just rallied for a best-effort to get it in, because
> > > it would be a nice to have, after finding out at F3 that it wouldn't
> > > work.
> > >
> > > As it is, the patch that is already in Quantum should be enough to get
> > > us going for Folsom if we can also get the patch into Nova. The two
> > > patches pending review can be backported, if necessary.
> > It took me a while to make any sense of this
> > This change which was merged into openstack-common a few days ago:
> > https://review.openstack.org/11408
> > is what changed the message format?
> > I must admit I didn't realize there was a backwards compatibility issue
> > with that patch.
> > So, the message format used by zmq in Nova is incompatible with what's
> > used in Quantum.
> > At this point I'd be inclined to document the zmq driver as unstable and
> > warn users that it's only included in Folsom as a "preview". Making
> > incompatible changes days before the release should tell us that we're
> > not ready to commit to maintaining compatibility with this driver yet.
> > If we don't document it as unstable, we have two choices before the
> > final Folsom release - either merge the new format into Nova or revert
> > it from Quantum.
> Please note: the zmq change in quantum was merged into master (i.e.,
> grizzly) but was not merged into milestone-proposed (i.e., folsom),
> since problems were discovered after the initial merge, but prior to
> deciding whether to include it in Folsom. Thus, I don't think we
> need to worry about reverting anything in Quantum, at least not for
> > Cheers,
> > Mark.
> Dan Wendlandt
> Nicira, Inc: www.nicira.com (http://www.nicira.com)
> twitter: danwendlandt
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