[ovs-discuss] ovs bridge mac address selection in the VM launched by openstack

[Ben Pfaff]

On Wed, Jan 15, 2014 at 04:07:08PM -0800, Chengyuan Li wrote:
> We created a ovs bridge br0 in a VM launched by openstack, and add eth0 as
> its port, assign the IP address to br0 port instead of eth0. But the br0 is
> not reachable from external, before bridge is created, eth0 is working well
> in the VM.
> 
> The reason is that br0 doesn't get the same mac address as eth0.
> eth0 mac address in openstack VM starts with "fa" which U/L bit is set, but
> openvswitch doesn't select any Local address for bridge port, it causes ovs
> bridge doesn't work in the VM.
> 
> One question is that why openvswitch limits Local address to be
> used?

Local addresses are usually randomly generated.  OVS tries to get a
permanent MAC address that isn't going to be so volatile.

> Secnond,
> Is there any solution to use ovs bridge in the VM if I don't want manually
> change br0's mac address?

You can write a script.