Re: Question to new network device names
On Thu 24 Aug 2017 at 09:17:00 (-0400), The Wanderer wrote:
> On 2017-08-24 at 07:52, tomas@tuxteam.de wrote:
>
> > On Thu, Aug 24, 2017 at 01:11:27PM +0200, Hans wrote:
> >
> >> Hi folks,
> >
> >> I stumbled over the new network names (i.e. wl0p8 instead of wlan0), and of
> >> course I know, that this is obviously the newe standard (please correct me, i
> >> I am wrong).
>
> >> So, what is the status today? How have people accepted the new names also for
> >> long running systems?
> >
> > I'd say: if you have a box with a huge number of interfaces, or if your
> > interface's hardware is brought up dynamically (picture a bunch of USB
> > hubs with 16 eth interface adapters at its tips, to have something your
> > phantasy can attach to), where the loading order of the corresponding
> > kernel modules determine who is first and who is last, whoever is eth0
> > and whoever is eth15 may change from boot to boot.
> >
> > You don't want that, especially when those are attached to different
> > networks (picture a firewall/router...)
> >
> > A similar case is when the interfaces come and go (e.g. plugging in and
> > out said USB adapters. All this doesn't need to be USB -- in the more
> > expensive world you can plug in (and out!) RAM and CPUs, while the
> > system is running).
> >
> > Predictable names (try to) bring up the "same" interface with the "same"
> > name each time (although "same" itself isn't well-defined; IMHO this
> > makes a 100% job impossible anyway).
>
> 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. As such, the scenario in which this naming scheme makes interface
> names more predictable is not one which most people will ever encounter.
> (...which calls into question the appropriateness of making this scheme
> the default.)
>
> 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.
>
> On that basis and from that perspective, the choice of "predictable
> network interface names" as the label for this naming scheme seems
> downright Orwellian.
Running wheezy and jessie, the lspci output from this laptop included
the lines
02:02.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5705 Gigabit Ethernet (rev 03)
02:04.0 Network controller: Intel Corporation PRO/Wireless 2200BG [Calexico2] Network Connection (rev 05)
so it was "predictable¹" that installing stretch would yield these:
kernel: [ 111.443209] tg3 0000:02:02.0 enp2s2: renamed from eth0
kernel: [ 134.994910] ipw2200 0000:02:04.0 wlp2s4: renamed from eth0
in its syslog. In case the eth0 duplication perplexes you, the
wireless card in squeeze, wheezy and jessie is called eth1. Don't ask
me why. That *was* unpredictable AFAICT.
¹Predictability is based on the output of lspci, according to the
page referenced earlier.
Cheers,
David.
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