Re: [OE-core] [PATCH] systemd: Allow overriding PNI name policies

[Ross Burton <Ross.Burton@arm.com>]

On 15 Apr 2025, at 07:56, Koen Kooi via lists.openembedded.org <koen.kooi=oss.qualcomm.com@lists.openembedded.org> wrote:
> 
> > It's very difficult to configured systemd in a way that is acceptable
> > to everyone, and I'm not sure adding variable "knobs" for every
> > possible configuration option is feasible for systemd.

My 2c is that I agree with Josh.

I think that we need some helper classes to make it simple to configure systemd at a higher level in a separate recipe, by dropping in configuration fragments and links as needed. This separate recipe could be machine-specific, unlike the systemd recipe itself.  We could then remove the PNI logic from systemd itself (and any other half-attempts at configuration too).

> For me, the issue is that OE-core adds the MAC naming feature that upstream has disabled by default, which gives me unpredictable names for various on-SoC network interfaces[1]. Having a way, supported by OE-core, to disable the addition that results in predictable names not being predictable would be great. It would make PNI function as intended :)

Amusingly, the mac naming was added for some SoCs that don’t have anything else (oe-core 4a7b42fc and 37bd8e8d).  It’s almost like this is a machine-specific configuration that shouldn’t be part of the core systemd recipe at all…

I’m more than half tempted to revert the bulk of the PNI policy patches (leaving just the on/off toggle, without altering the behaviour otherwise), and if someone wants to override them on a per-machine basis then they can, using a per-machine recipe that writes a drop file to /usr/lib/systemd/network/99-default.link.d/pni.conf. 

Ross