[systemd-devel] How to disable Predictable Network Interface Names using a drop-in?

[Lennart Poettering]

On Mon, 20.02.17 17:38, Lennart Poettering (lennart at poettering.net) wrote:

> On Sun, 19.02.17 12:54, Marc Haber (mh+systemd-devel at zugschlus.de) wrote:
> 
> > On Mon, Feb 06, 2017 at 09:56:30PM +0100, Lennart Poettering wrote:
> > > On Sat, 21.01.17 21:20, Marc Haber (mh+systemd-devel at zugschlus.de) wrote:
> > > > On Fri, Jan 20, 2017 at 02:51:00PM +0000, Patrick Schleizer wrote:
> > > > > I've learned about the kernel parameter and symlink ways to disable
> > > > > predictable network interface names.
> > > > 
> > > > What would be the "symlink way"?
> > > 
> > > Linking the relevant .link file to /dev/null in /etc.
> > 
> > What if there is no .link file and the Interfaces just come up as
> > enp8s0 and wlp2s0
> 
> We ship a default fallback .link file in systemd upstream:
> 
> /usr/lib/systemd/network/99-default.link
> 
> If your distro removes that, then I'd recommend contacting your distro
> for help, as they are clearly deviating from upstream defaults, and I
> have no idea where the naming is enforced then.
> 
> > > However, if you pick your own names outside of the kernel's
> > > namespaces, then all is good, and that's actually what we
> > > recommend. (Though I'd do it by dropping in some .link files with the
> > > right [Match] sections to make this happen, not bother with udev
> > > rules, but either works)
> > 
> > [2/5147]mh at swivel:~ $ cat /etc/systemd/network/lanc0.link
> 
> Consider naming the file 50-lanc0.link or so, so that it takes
> precedence over 99-default.link if that's shipped by your distro. If
> it isn't, please contact your downstream distro for help (see above).

BTW, all of the above is documented in systemd.link(5). My
recommendation is always to check the documentation first.

Lennart

-- 
Lennart Poettering, Red Hat