[libvirt-users] Using libvirt with a preexisting network infrastructure

[Vegard Vesterheim]

I have a server running Ubuntu natty (libvirt 0.8.8) with separate
ethernet interfaces. I have created an unnumbered bridge for each
interface, these are connected to an already established network
infrastructure, with preexisting DHCP and DNS services.

I would like to handle *establishment* of these bridges outside libvirt
(via /etc/network/interfaces), but still have them defined as networks
within libvirt. So, libvirt shall not *configure* the bridges, just be
aware of their existence and connect each VM to its configured
bridge. This way I can use virt-manager/libvirt to connect my virtual
hosts to the correct network. The libvirt commands net-start,
net-destroy would become no-ops. It seems that libvirt is geared towards
handling all network configuration itself, but I do not need help from
libvirt for establishing the bridges, DHCP and DNS.

I know that I can edit the <interface> element in the VM XML-files
after creation, to assign a virtual host to a bridge, like
this:

  <interface type='bridge'>
      <source bridge='br22'/>
      ....
  </interface>

This works, but I would like to do this with libvirt mechanisms. Is this
possible?

 - Vegard V -