Re: [libvirt] [RFC] Vhost-user backends cross-version migration support

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

On Thu, Feb 02, 2017 at 03:14:01PM +0100, Maxime Coquelin wrote:
> 
> 
> On 02/01/2017 12:41 PM, Daniel P. Berrange wrote:
> > 
> > It depends where / how in OVS it needs to be set. The only stuff libvirt
> > does with OVS is to run 'add-port' and 'del-port' commands via the ovs
> > cli tool. We pass through arguments from the port profile stored in the
> > XML config.
> > 
> >   <interface type='bridge'>
> >     <source bridge='ovsbr'/>
> >     <virtualport type='openvswitch'>
> >       <parameters profileid='menial' interfaceid='09b11c53-8b5c-4eeb-8f00-d84eaa0aaa4f'/>
> >     </virtualport>
> >   </interface>
> > 
> > eg those things in <parameters/> get passed as cli args to the 'add-port'
> > command. Soo if add-port needs this new version string, then we'd need
> > to add the version to the openvswitch virtualport XML.
> > 
> > If the version is provided to OVS in a different command, then it would
> > probably be outside scope of libvirt.
> 
> I think it would make sense to be a parameter of the add-port command.
> But it would be for vhost-user related add-port command, I didn't find
> where/if this is managed in libvirt XML.

For vhost-user, libvirt does not have any interaction with OVS at
all. If the thing that's using the vhost-user UNIX socket, in turn
connects to OVS, that's outside scope of libvirt. IOW, for vhost-user
OVS it seems like that job is for Nova / os-vif to solve.

Regards,
Daniel
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