[libvirt] Re: [netcf-devel] [RFC] Reporting host interface status/statistics via netcf/libvirt, and listing active vs. inactive interfaces

[David Lutterkort]

On Wed, 2009-06-17 at 19:27 +0100, Daniel P. Berrange wrote:
> Hmm, this seems wrong to me. 'connections' are an application level
> concept. The libvirt API should be exposing all the interfaces on 
> the host, so you should see all the br0, bond0, and eth0  & eth1
> devices for a bridge on top of a bond.  An application using libvirt
> can filter this to only show the logical 'connections' if required.
> 
> If you start out with a fresh machine and virConnectListInterfaces
> gives you back 2 objects for 'eth0' and 'eth1', I would not expect
> these objects to disappear from the API when I created a 'bond0' out
> of them.

We probably need two different views of the network setup: one that
considers network devices (and in that area, you would always see eth0,
eth1 etc. even when they are enslaved to bridges/bonds) and one that
considers connections; on some OS's, it doesn't make sense to talk about
eth0 when it's enslaved to a bridge br0 for config purposes. [1] has an
example of how a bridge is configured on Debian - note that eth0 should
not be mentioned anymore outside of the br0 setup.

Of course, eth0 is still around as an interface/device, and, at a
minimum, has statistics that are different from the bridge's statistics.

>From the netcf side, we should probably restructure the model to talk
about connections (roughly what netcf_if is today, maybe renamed to
netcf_conn) and interfaces/devices, and a way to get the devices from a
connection, so that you can list all the interfaces involved in a bridge
(connection)

David

[1] http://compsoc.dur.ac.uk/~djw/qemu.html