KVM: Problem creating VM with vmbuilder and bridged Network

[pred2k]

Hi, i installed Ubuntu 8.10 server and choose the Package "Virtual Machine host".
I installed the python-vm-builder to create a new VM based of the JeOS.

Because i wanted a bridged Network i changes the interface Element in /etc/vmbuilder/libvirt/libvirtxml.tmpl

<interface type='bridge'>
   <source network='br0'/>
</interface>

.. and created a dhdcp br0 Interface in the /etc/network/interfaces

Then i executed my vmbuilder command:

sudo vmbuilder kvm ubuntu --suite intrepid --flavour virtual --arch i386 -o --libvirt qemu:///system ...

and during creating the VM, following error appeared:

libvir: QEMU error : internal error No <source> 'dev' attribute specified with <interface type='bridge'/>
2008-11-01 17:25:58,925 INFO     Cleaning up
Traceback (most recent call last):
  File "/usr/bin/vmbuilder", line 29, in <module>
    VMBuilder.run()
  File "/usr/lib/python2.5/site-packages/VMBuilder/__init__.py", line 66, in run
    frontend.run()
  File "/usr/lib/python2.5/site-packages/VMBuilder/plugins/cli/__init__.py", line 67, in run
    vm.create()
  File "/usr/lib/python2.5/site-packages/VMBuilder/vm.py", line 447, in create
    self.deploy()
  File "/usr/lib/python2.5/site-packages/VMBuilder/vm.py", line 177, in deploy
    if getattr(plugin, 'deploy')():
  File "/usr/lib/python2.5/site-packages/VMBuilder/plugins/libvirt/__init__.py", line 61, in deploy
    self.conn.defineXML(vmxml)
  File "/usr/lib/python2.5/site-packages/libvirt.py", line 866, in defineXML
    if ret is None:raise libvirtError('virDomainDefineXML() failed', conn=self)
libvirt.libvirtError: virDomainDefineXML() failed internal error No <source> 'dev' attribute specified with <interface type='bridge'/>

i don't know whats wrong, because i have a <source>-Element beflow the <interface>.

[nknight]

I just fought through this myself. The docs are in error, as is the error message given by vmbuilder.

You need to replace this:

<interface type='bridge'>
   <source network='br0'/>
</interface>

With this:

<interface type='bridge'>
   <source bridge='br0'/>
</interface>

The error from vmbuilder really should have been "No <source> 'bridge' attribute[...]".

[pred2k]

You need to replace this:

...

With this:

<interface type='bridge'>
   <source bridge='br0'/>
</interface>

Yep, thats it! Thanks for that advice. =D>

Should be changed in the VMBuilder-howto asap.