[libvirt] libvirt: use existing network bridge

[Daniel Berteaud]

Le lundi 19 octobre 2009 à 09:14 +0200, Chris Lalancette a écrit :
> Sascha Frey wrote:
> > Hi,
> > 
> > I met a problem setting up virt-manager and libvirt:
> > 
> > I want to use an existing customized network bridge with libvirt
> > (I need special iptables rules and a custom DHCP setup).
> > 
> > So I created a network definition file like this:
> > <network>
> >   <name>NAT</name>
> >   <bridge name='br-nat' />
> > </network>
> > 
> > Unfortunately, I'm unable to activate this network, because libvirt
> > tries to create the bridge `br-nat' and fails, because it already
> > exists:
> > 
> > # virsh net-start NAT
> > error: Failed to start network NAT
> > error: cannot create bridge 'br-nat': File exists
> > 
> > 
> > I just want libvirt to attach the guest's tap devices to this existing 
> > bridge. I don't want libvirt to manage the network.
> > 
> > Is there any chance to realize this set-up?
> > It should work with virt-manager using the graphical wizard.
> 
> Yes, just don't define a new network.  To use existing bridges, you just need to
> edit your guest XML files to use something like:
> 
>     <interface type='bridge'>
>       <mac address='00:16:3e:4a:f6:89'/>
>       <source bridge='br0'/>
>     </interface>
> 
> Note that configured bridges should also show up in virt-manager, I believe.

Existing bridge shows up in virt-manager when run on the local machine.
If you use a remote connection (at least qemu+ssh), you don't see it,
you need to manually edit the guest XML.

(btw, is this a known "problem" or a bug ?)

Regards, Daniel



> 
-- 
Daniel Berteaud
FIREWALL-SERVICES SARL.
Société de Services en Logiciels Libres
Technopôle Montesquieu
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Mail: daniel at firewall-services.com
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