Open Stack

On Mon, Jul 07, 2014 at 02:38:57PM +0000, Dugger, Donald D wrote:
> Well, my main thought is that I would prefer to see the gantt split
> done sooner rather than later.  The reality is that we've been trying
> to split out the scheduler for months and we're still not there.  Until
> we bite the bullet and actually do the split I'm afraid we'll still be
> here discussing the `best` way to do the split at the K & L summits
> (there's a little bit of `the perfect is the enemy of the good' happening
> here).  With the creation of the client library we've created a good
> seam to split out the scheduler, let's do the split and fix the remaining
> problems (aggregates and instance group references).

> To address some specific points:

> 2)  We won't get around to creating parity between gantt and nova.  Gantt
> will never be the default scheduler until it has complete parity with the
> nova scheduler, that should give us sufficient incentive to make sure we
> achieve parity as soon as possible.

Although it isn't exactly the same situation, we do have history with
Neutron/nova-network showing that kind of incentive to be insufficient
to make the work actually happen. If Gantt remained a subset of features
of the Nova scheduler, this might leave incentive to address the gaps,
but I fear that other unrelated features will be added to Gantt that
are not in Nova, and then we'll be back in the Neutron situation pretty
quickly where both options have some features the other option lacks.

> 3)  The split should be done at the beginning of the cycle.  I don't
> see a need for that, we should do the split whenever we are ready. 
> Since gantt will be optional it shouldn't affect release issues with
> nova and the sooner we have a separate tree the sooner people can test
> and develop on the gantt tree.

If we're saying Gantt is optional, this implies the existing Nova code
is remaining. This seems to leave us with the neutron/nova-network
situation again of maintaining two code bases again, and likely the
people who were formerly fixing the bugs in nova scheduler codebase
would be focused on gantt leaving the nova code to slowly bitrot.

Regards,
Daniel
-- 
|: http://berrange.com      -o-    http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org              -o-             http://virt-manager.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org       -o-       http://live.gnome.org/gtk-vnc :|