Re: [libvirt-users] virtual networking - virbr0-nic interface
On 10.09.2012 23:09, Shantanu Pavgi wrote:
I need some help in understanding libvirt's virtual networking. I have configured
bridged networking (shared physical device) on libvirt+KVM system which is working fine.
Also, I am using default NAT network on with virbr0 bridge device and virbr0-nic. I would
like to get better understanding on virbr0-nic works in this virtual network
configuration. I understand that traffic from virbr0 bridge is forwarded through host
system's physical interface eth0 using iptables rules, but I am not following
virbr0-nic's working here. I see it attached to virbr0 bridge device though.
{{{
$ brctl show
bridge name bridge id STP enabled interfaces
br0 8000.14feb5dc4f06 no eth0
vnet1
virbr0 8000.525400f5a4ed yes virbr0-nic
vnet2
}}}
Any pointers on how virbr0 and virbr0-nic work would be really helpful.
It's a workaround for kernel bug/feature. The bridge's MAC is copied
from the first NIC attached. So if one detach all interfaces from a
bridge and then attach just one, the bridge will lost previous MAC and
gain a new one - just the same as the attached interface has.
So if libvirt has to ensure a MAC for virtual bridge - it creates this
dummy device (no traffic is routed through though) and just attach it to
the virtual bridge.
Regards,
Michal
--
Thanks,
Shantanu
_______________________________________________
libvirt-users mailing list
libvirt-users(a)redhat.com
https://www.redhat.com/mailman/listinfo/libvirt-users