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

Chengyuan Li chengyuanli at gmail.com
Fri Jan 17 04:29:12 UTC 2014


Hi Ben,

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

This is true for OVS running on the bare mental.
But if the OVS is running on the virtual machine, even though eth0's mac is
"local" type, we can't regard it as "volatile", it should be treated as
normal mac address.


Regards,
CY.


On Thu, Jan 16, 2014 at 1:38 PM, Ben Pfaff <blp at nicira.com> wrote:

> 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.
>
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