openstack team mailing list archive

[Eric Windisch <eric@xxxxxxxxxxxxxxxx>]

> > 
> > The issue reported with that is that it creates a smaller space for
> > collision amongst OpenStack users. Encouraging people to use
> > locally-assigned OUI or buy their own might therefore be a better strategy.
> > 
I see the problem being that we shouldn't automatically choose a random OUI. Administrators might be using local OUIs elsewhere.   Isn't collision with other devices that might have locally-assigned OUIs more immediately threatening than colliding with deployments in (presumably) physically separate domains?

If a random OUI might be dangerous and we're going to choose a non-random OUI, why not make it our own?

Xen, VMware, and HyperV provide their own OUI for automatically generated addresses. Yes, these collide between deployments. XenSource does go so far as to provide the following recommendation, to use one of the following strategies in order of preference:

> 1) Use your own OUI
> 2) Use a random OUI
> 3) Use the XenSource-assigned OUI
> 

When I first deployed Xen, it would choose #3 by default, because while it wasn't the best option overall, it worked deterministically out of the box without risk of collisions (outside of other Xen host's VMs).  Colliding with artifacts of your own software is better than colliding with local operator configurations and preferences.

Regards,
Eric Windisch