[libvirt] How can I attach a network interface to KVM machine

[Daniel P. Berrange]

On Wed, Apr 15, 2009 at 02:35:41PM +0400, Anton Protopopov wrote:
> 2009/4/7 Daniel P. Berrange <berrange at redhat.com>
> 
> > On Tue, Apr 07, 2009 at 05:30:02PM +0400, Anton Protopopov wrote:
> > > Hi.
> > >
> > > When I am trying to attach an interface
> > >     <interface type='bridge'>
> > >       <mac address='52:54:00:db:1a:bb'/>
> > >       <source bridge='mkvebr0'/>
> > >     </interface>
> > > libvirt reports me, that
> > >      libvirt.libvirtError: this function is not supported by the
> > hypervisor:
> > > this device type cannot be attached
> > >
> > > Is there a legal way to attach a network interface to QEMU/KVM machine?
> >
> > Not at this time. The QEMU monitor interface doesn't provide sufficient
> > functionality to be able todo this, because there's no way to pass have
> > libvirt create & setup the TAP device, and then pass it to QEMU. The
> > QEMU monitor needs to gain the ability to do SCM_RIGHTS to accept an
> > open file handle before we can hotplug NICs in any useful manner.
> >
> And what about attaching a device to stopped machine?
> Stop, attach, and start. Just as temporary decision.

You can already add devices to stopped machines just by defining a new
config file for them. We do need to make the attach/detach APIs for with
inactive guests too for QEMU driver, since we allow this in the Xen
driver already and there's no particular reason to deny it.

Regards,
Daniel
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