Re: [Libvir] Re: [PATCH 1/2] virDomainMigrate implementation (Xen only, no remote, no qemu, no virsh)

["Daniel P. Berrange" <berrange redhat com>]

On Mon, Jul 16, 2007 at 10:58:18AM -0500, Anthony Liguori wrote:
> John Levon wrote:
> >On Mon, Jul 16, 2007 at 10:47:59AM -0500, Anthony Liguori wrote:
> >
> >  
> >>>If we need to express some choice of data channel, TCP, vs SSH, vs 
> >>>SSL/TLS
> >>>then figure out a way to expose that in the API with an hypervisor 
> >>>agnostic
> >>>way. Exposing raw QEMU migration URIs is *not* hypervisor agnostic.
> >>>      
> >>Why?  If nothing but QEMU support ssh:// then exposing an API to do SSH 
> >>migration isn't really hypervisor agnostic.  It's an API for QEMU.
> >>    
> >
> >You're presuming things never change (and that new backends never get
> >added to libvirt!)
> >  
> 
> There's a big difference between taking two implements of SSH migration, 
> finding the commonality, and building an abstraction verses just 
> modeling the KVM ssh:// URI.  The chances that a second implementation 
> can be exposed nicely through the later is small.
> 
> What I'd rather see is something that exposed the bits of both KVM and 
> Xen and then a second "agnostic" interface.  For instance, for KVM you 
> may have:
> 
> virDomainMigrateKVM(..., URI);
> 
> For Xen you'd have:
> 
> virDomainMigrateXen(..., hostname, port);

I don't see the point in having separate methods for those when Xen's
hostname+port can be formatted as a URI too.

> But then you'd also have:
> 
> virDomainMigrate(dom, connPtr);

So perhaps we should think about 2 possible APIs:

  - One based on a URI string
  - One based on a pre-existing virConnectPtr

Or, have 1 API, and have the URI string optional and virConnectPtr be
compulsory ?

Dan.
-- 
|=- Red Hat, Engineering, Emerging Technologies, Boston.  +1 978 392 2496 -=|
|=-           Perl modules: http://search.cpan.org/~danberr/              -=|
|=-               Projects: http://freshmeat.net/~danielpb/               -=|
|=-  GnuPG: 7D3B9505   F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505  -=|