Proposal: enable stateless persistant network interface names

[Martin Pitt]

Hello,

Karsten Merker [2015-05-11 20:22 +0200]:
> >From what Ben Hutchings has described in
> <1431294933.2233.66.camel at decadent.org.uk>, the race condition
> could easily be avoided with the current codebase by simply not
> using "eth" as the prefix, but e.g. "en".

Right, that would solve one problem, but not the others.

> Could you explain why the existing code does not provide stable
> names in virtual machines?  As long as the virtual ethernet
> controller keeps the same MAC address over time (which I believe
> to be the normal case), I see no reason why the existing codebase
> should not provide stable names in a VM in the same way it does
> on physical hardware.

I'm afraid you have to ask folks more familiar with clouds about the
"why", but it seems MAC addresses change all the time there as with
every new instance or even boot you get a different virtual ethernet
card assigned. See all the reports that we are getting about adding
entries to the blacklist.

> As "slot" has been shown to be not really stable for a number of
> use cases (even for PCI, see above), I think that "mac" is the
> only way that works for all cases.

It clearly doesn't work for "all cases", like replacing network cards
(in physical servers, but this is what by and large happens in clouds
too), or where you have to rely on the location of cards instead of
their MACs (like running the same config on a rack of servers, where
what you see, wire, and configure are port locations).

Anyway, I do see that we want to use MAC addresses by default for at
least USB.

Thanks,

Martin
-- 
Martin Pitt                        | http://www.piware.de
Ubuntu Developer (www.ubuntu.com)  | Debian Developer  (www.debian.org)