Proposal: enable stateless persistant network interface names

[Josh Triplett]

Martin Pitt wrote:
> Proposal
> --------
> I propose to retire [mac], i. e. drop
> /lib/udev/rules.d/75-persistent-net-generator.rules and enable
> [ifnames] by default.
> 
> This will provide the new stable interface names for all new
> installations, stop the different handling of server/client, work with
> system-image, and stops the woes cloud providers have with Ubuntu's
> [mac].
> 
> I'm happy to ship a commented example udev rule that shows how to
> configure your own names, if you want to continue using MAC based
> schemas, or call your interfaces "internet" and "intranet" or the
> like.  This makes it easier to see how to do custom naming than having
> to start from scratch.
> 
> For upgrades: As we don't know what refers to existing stable network
> names, we can't ever safely remove a generated
> /etc/udev/rules.d/70-persistent-net.rules. So when we do the above,
> names on existing installations will *not* change (as
> 70-persistent-net.rules trumps [ifnames]).
> 
> So we can only let time and replacing/reinstalling machines take care
> of this. /etc/udev/rules.d/70-persistent-net.rules requires zero
> maintenance from us (it's just like the admin had manually set their
> own rules).
> 
> Opinions?

Having spent a non-trivial amount of time fighting persistent-net.rules
on various systems, I'd very much welcome this change.

To help migrate existing systems, I'd suggest including a NEWS.Debian
file that explains the change, and recommends deleting
/etc/udev/rules.d/70-persistent-net.rules on systems that don't depend
on the exact names (for instance, systems that run NetworkManager rather
than hard-coding network configuration in ifupdown's
/etc/network/interfaces).

- Josh Triplett