Hello!

I've faced a weird problem. And I totally can't understand how libvirt handles networks. The thing that i need to do is simple. I create a bridge in my ubuntu host, the following config:

iface eth0 inet manual

auto br0
iface br0 inet dhcp
  bridge_ports eth0
  bridge_stp on
  bridge_maxwait 0

That's OK, and my bridge turns up automatically. But I don't understand why libvirt can't use it, it always want to create bridge on its own. So that when I try to create bridged network with the command:
  virsh virsh net-create net.xml

net.xml contents:
 <network>
  <name>virbreth0</name>
  <bridge name='br0' stp='on' delay='0' />
 </network>

I always get error ===>
error: Failed to create network from net.xml
error: cannot create bridge 'br0': File exists

That's pretty obvious that libvirt wants to create bridge on its own. But what should I do in my specific situation. May be there is a workaround. I appreciate any help and ideas...

Thanks for your answers.

Best regards,
  Denis Barishev.