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Re: Question to new network device names




On Thu, Aug 24, 2017 at 09:17:00AM -0400, The Wanderer wrote:
> However, I'll point out that machines with this many network interfaces
> are *by far* the exception rather than the rule; indeed, even machines
> with more than *one* interface each of wired and wireless are reasonably
> rare.

In the home desktop space, perhaps.  When you deal with rackmount
servers, OTOH, four (wired) network ports is pretty standard these days.

Of course, they're all on the same bus and using identical hardware/
firmware, so the "order might change based on which drivers load first"
case still doesn't apply.

> To the best of my awareness, the rationale for calling this "predictable
> network interface names" is that, on a single computer which has
> multiple network interfaces of a given type, this naming scheme makes
> it possible to predict *from one boot to the next* what the name of each
> one will be. On such a computer, this is extremely valuable.
> 
> By contrast, on a computer which has at most one interface of a given
> type, this naming scheme provides - so far as I can tell - no advantage
> at all.
> 
> What's more, when working on *multiple* computers of that latter type,
> this naming scheme makes it impossible to predict *from one computer to
> the next* what the name of the sole available interface will be.
> 
> As such, IMO this naming scheme makes network-interface names
> significantly *less* predictable in the real-world scenario which is
> most commonly encountered.

This closely parallels the move from using /dev/sdXn to UUIDs for
referring to filesystems.  Probably superior in theory and doesn't cause
any issues as long as you're dealing with a single machine and
unchanging hardware configuration... but then you have a drive failure,
restore your backups onto new hardware, and you're hosed because the
system wants to boot from a UUID that no longer exists.  (Yes, you can
recover from that situation - I know because I've had to do it - but it
doesn't Just Work(TM) effortlessly.)

-- 
Dave Sherohman