Open Stack

On Mon, Oct 03, 2016 at 10:11:34AM +0300, Timofei Durakov wrote:
> Hi team,
> 
> I agree that it's kind of strange thing that nova dumps xml definition to
> the disk but doesn't use it(at least I do not aware of it).
> How the proposed changed would be aligned with other drivers? The worst
> case I could imagine here is that libvirt has an xml as a source of truth,
> while others use nova for the same purposes. Taking that into account, the
> question here would be:  why not to store all required information(e.g.
> boot order) in DB instead?

That is duplicating information already stored in libvirt - any time you
change the guest you have the job of updating the DB copy to mirror this
change. This gets particularly fun (aka error prone) during migration
if there's a failure during migration, as you can get the two copies out
of sync (eg if libvirt completes, but something causes an exception in
nova's post-migration logic).

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