[libvirt] RFC: configuring host interfaces with libvirt

[Daniel P. Berrange]

On Fri, Jan 16, 2009 at 12:44:21PM +0000, Richard W.M. Jones wrote:
> On Fri, Jan 16, 2009 at 12:41:42PM +0000, Daniel P. Berrange wrote:
> > On Fri, Jan 16, 2009 at 12:35:55PM +0000, Richard W.M. Jones wrote:
> > > On Fri, Jan 16, 2009 at 01:13:18AM +0000, David Lutterkort wrote:
> > > > For certain applications, we want libvirt to be able to configure host
> > > > network interfaces in a variety of ways; currently, we are most
> > > > interested in teaching libvirt how to set up ordinary ethernet
> > > > interfaces, bridges, bonding and vlan's.
> > > [...]
> > > > 3. Implementation
> > > > =================
> > > > 
> > > > Configuring network interfaces is highly OS and OS-variant/distro
> > > > dependant. There are at least two different ways how libvirt can go about
> > > > modifying the host to create interfaces:
> > > > 
> > > >   1. Modify the system's network setup scripts (ifcfg-XXX on RH)
> > > > 
> > > >   2. Directly use the system's network utilities like ifconfig
> > > > 
> > > >   3. Rely on NetworkManager (not an option right now, as NM doesn't know
> > > >     about bridges and the like)
> > > 
> > > I must be missing something here ... how can libvirt modify stuff
> > > inside the guest?
> > 
> > It can't - this is all about configuring & managing networking on the
> > host OS.
> 
> Well OK then, how does the information get passed into the guest?

There isn't anything to pass into the guest . This is about how to
configure host network interfaces for bridging, bonding, vlans, etc
eg, So you can take an host with a NIC, eth0, put that NIC into a 
bridge, br0, and thus now have the ability to create guests using
a bridged networking configuration.

As it currently stands admins have to manually configure bridges
in their host by editing /etc/sysconfig/networking-scripts/ifcfg-eth0
This proposal is to provide an API for doing this in the host instead
of requiring that admin do it manually ahead of time.

Regards,
Daniel
-- 
|: Red Hat, Engineering, London   -o-   http://people.redhat.com/berrange/ :|
|: http://libvirt.org  -o-  http://virt-manager.org  -o-  http://ovirt.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
|: GnuPG: 7D3B9505  -o-  F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|