On Wed, Jul 03, 2013 at 09:39:57AM +0300, Dan Kenigsberg wrote: > 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.
No, it doesn't really work properly. Not all type=network configs are based on tap devices. We need to be able to ask QEMU to remove the netdev backend, without affecting the guest device, and then add in a new netdev backend. We should have asked for this when we first did dynamic network re-configuration, but we took the easy way out back then. We need to fix this properly so that all possible config changes work. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
