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Re: Naming of network devices - how to improve it in buster




On Wed, 12 Jul 2017, Michael Biebl wrote:
> Am 12.07.2017 um 18:58 schrieb Matt Zagrabelny:
> > On Wed, Jul 12, 2017 at 11:47 AM, Michael Biebl <biebl@xxxxxxxxxx
> > <mailto:biebl@xxxxxxxxxx>> wrote:
> > 
> >     Am 12.07.2017 um 17:35 schrieb Marc Haber:
> >     > My finger memory will still type tcpdump -i eth0 before the brain can
> >     > intervene ten years from now.
> > 
> >     thankfully tcpdump (and lots of other tools) have nice shell completion.
> >     tcpdump -i <TAB> works great her.
> > 
> > 
> > Agreed. However, I'd still rather deal with names like /dev/sda and eth0
> > than /dev/disk/by-id/ata-SanDisk_SSD_U100_252GB_122339300522 and en<blah>.
> > 
> > It is kind of like using people's first names as opposed to their Social
> > Security Number (in US) or other form of national identification. I know
> > when I can use the name Matt and I know who it refers to, even if
> > another Matt enters the room. I'm comfortable with eth0 being the name,
> > even when another interface appears.
> > 
> > I completely understand, and largely agree with, the need for persistent
> > naming - but I think we are selling ourselves and our users short by not
> > pressing harder for network interface aliases. It seems to be too useful
> > of a solution for this problem.
> 
> Indeed, the best solution would be to never rename the interfaces and
> simply create aliases / symlinks. Then again, I'm no kernel hacker so I
> have no idea if that would be feasible.

ip link set dev eth0 alias foo0

But don't expect everything to work right with this: it is the same
mechanism that was used for adding "extra IP addresses" when using
braindamaged crap from a decade ago (old ifconfig), so I very much bet
there are going to be stuff misbehaving...

The obvious thing would be to just tell the kernel to change namespaces
in the first place (kconfig + command line), and have userspace aware of
the kernel namespace using sysfs.  Just beware the kernel default would
be "unspecified" (and not "eth*", etc) because this is not central
policy in the kernel at all).  I have never understood why this wasn't
done, since it is absolutely trivial to implement, even if it is a lot
of busywork (you have to patch each !@#$ network driver).  But you could
clean up a _LOT_ of crap kernel side while at it, AND create both a
central point for naming this stuff AND better device grouping, so it
would be worth the trouble.  And it would be opt-in, default N, and
detectable from userspace, so that it would not regress anything not
prepared for it.

-- 
  Henrique Holschuh