[Qemu-devel] Re: [PATCH v3 0/5] Add QMP migration events

[Luiz Capitulino <lcapitulino@redhat.com>]

On Wed, 16 Jun 2010 21:10:04 +0200
Juan Quintela <quintela@redhat.com> wrote:

> Luiz Capitulino <lcapitulino@redhat.com> wrote:
> > On Tue, 15 Jun 2010 17:24:59 +0200
> > Juan Quintela <quintela@redhat.com> wrote:
> 
> >> >
> >> >  I still don't see the need for MIGRATION_STARTED, it could be useful in
> >> > the target but I'd like to understand the use case in more detail.
> >> 
> >> At this point, if you are doing migration with tcp, and you are putting
> >> the wrong port on source (no path or any other error), you get no info
> >> at all of what is happening.
> >
> >  Shouldn't the migrate command just the return the expected error?
> 
> No.  Think you are "having troubles".  You try to find what happens.
> launch things by hand.  And there is no way to know if anybody has
> conected to the destination machine.  Some notification that migration
> has started is _very_ useful.  expecially when there are
> networks/firewalls/... in the middle.

 [...]

> That is it.  But you continue telling that going to the old house and
> doing a info migrate is a good interface.

 I'm sorry? When did I ever claimed such a thing?

 First point: all you describe is MIGRATION_CONNECTED, at the end of the day
it would do exactly what you want for MIGRATION_STARTED.

 The second, and most important point, is that we're trying not to make
things worse. Adding a number of events to circumvent a bad designed
command and having the wrong expectations (ie. help developer debugging)
is a clear recipe for disaster.

 Anyway, I think it doesn't matter anymore, as QMP is not going to be declared
stable for 0.13. In this case we'll have enough time to design the proper
interface.

> To add insult to injury, the problem is that libvirt people are not
> collaborative, and expect things that can't be done, are uncooperative,

 Again, I've never claimed that and I think you're taking this thread to
the wrong direction.

> ....
> 
> Libvirt folks "also" do lots of things wrong, they are not perfect.  But
> it in this case, who is being completely unreasonable is qemu land.
> 
> Later, Juan.
>