Re: [libvirt] configuring a disconnected <interface>

On Tue, Jul 02, 2013 at 05:32:20PM -0400, Laine Stump wrote: > On 07/02/2013 04:07 PM, Dan Kenigsberg wrote: > > On Mon, Jun 24, 2013 at 11:22:16AM +0100, Daniel P. Berrange wrote: > >> On Sun, Jun 23, 2013 at 03:34:06PM +0300, Dan Kenigsberg wrote: > >>> On Fri, Jun 21, 2013 at 04:31:53AM -0500, Daniel P. Berrange wrote: > >>>> So I'm not inclined to support this disconnected mode. > >>> Disconnected mode exists in actuality. It has valid use cases in the > >>> virtual world as well. I would like to discuss the domxml schema for > >>> representing it, and then, hopefully find the menpower to implement it > >>> outside the core libvirt team. So please, reconsider. > >> The XML schema is easy enough - it is just a new <interface type=none>. > >> Ideally we would want some kind of support in QEMU for this, concept > >> so that we don't have to have a hidden dangling tap device > > That would be cool indeed. It would make it possible to > > virDomainUpdateDevice() from a tap-based connectivity to non-tap one. > > > > Until we have something like that in qemu, would it be reasonable to > > implement <interface type=none> via a dangling tap? Wouldn't it be fine > > to limit changing type=none to type=network only to bridge-based > > networks? > > Well, that *is* how virDomainUpdateDevice behaves when switching from > one network connection to another - if the source and destination are > both implemented with tap, it works, otherwise it returns > OPERATION_UNSUPPORTED. My question is slightly different: it's about switching from one interface type (=none) to another (=network), not between two networks. I am asking whether it would be fine to implement type=none with tap, given this unsupportedness.