[systemd-devel] Support for unmerged-usr systems will be REMOVED in the second half of 2023

[Richard Purdie]

On Tue, 2023-06-13 at 15:59 +0100, Luca Boccassi wrote:
> On Tue, 13 Jun 2023 at 15:52, Richard Purdie
> <richard.purdie at linuxfoundation.org> wrote:
> > 
> > On Tue, 2023-06-13 at 15:31 +0100, Luca Boccassi wrote:
> > > On Tue, 13 Jun 2023 at 15:15, Richard Purdie
> > > <richard.purdie at linuxfoundation.org> wrote:
> > > > 
> > > > On Tue, 2023-06-13 at 11:29 +0100, Luca Boccassi wrote:
> > > > > On Tue, 20 Sept 2022 at 20:18, Luca Boccassi <bluca at debian.org> wrote:
> > > > > > 
> > > > > > Hello,
> > > > > > 
> > > > > > Following this thread started back in April:
> > > > > > 
> > > > > > https://lists.freedesktop.org/archives/systemd-devel/2022-April/047673.html
> > > > > > 
> > > > > > As far as we understand there are no distributions running or
> > > > > > optionally supporting systemd that have not either completed, or at
> > > > > > least started, the transition to merged-usr systems.
> > > > > > 
> > > > > > So, we are planning to drop support for unmerged-usr systems in the
> > > > > > first release that will happen in the second half of next year, I.E.:
> > > > > > any time starting from July 2023 (while we tend to release somewhat
> > > > > > regularly we do not have strict dates and deadlines, so right now it's
> > > > > > not possible to tell the exact version, but it will be of course
> > > > > > communicated once it becomes clear).
> > > > > 
> > > > > As previously announced, this is being prepared now and will be part of v254:
> > > > > 
> > > > > https://github.com/systemd/systemd/pull/27999
> > > > 
> > > > I'd note that nobody did resolve the issues for Yocto Project yet so
> > > > our CI will break if we try and upgrade :(.
> > > 
> > > Those issues are purely internal to Yocto's custom CI and completely
> > > unrelated to systemd, as they manifest without systemd being even
> > > enabled. The 'usrmerge' distro feature was added six years ago, in
> > > 2017, by Yocto developers:
> > > 
> > > https://git.yoctoproject.org/poky/commit/?id=178e983cf745fe32b199e0cbfe9777270124b186
> > > 
> > > If even Yocto developers cannot manage to fix internal CI issues
> > > created by internal features added by Yocto developers in 6 years,
> > > there's hardly anything outsiders could possibly do, I'm afraid.
> > 
> > The issue is that Yocto Project supports a variety of configurations
> > and systemd has decided to drop support for some of them.
> > 
> > Nobody has done the work to migrate the configuration combinations
> > being dropped in Yocto Project.
> > 
> > Distro features are optional in Yocto Project, we don't force people to
> > use them. There are plenty of people with products shipping in the wild
> > which do not use the "usrmerge" feature. Our own test matrix hasn't
> > been adjusted to force usrmerge for systemd, nor is the documentation
> > or migration information present for that change.
> > 
> > This is not an issue caused by our "internal features" and to claim
> > that is farcical.
> 
> It's Yocto's own unit test that fails, internally written, related to
> RPM or so IIRC, with no involvement of the systemd recipe whatsoever.
> Evidently that unit test was not tested in combination with the distro
> feature when it was added by the commit linked above. Once again,
> unrelated to systemd's recipe. You can fix it, or you can drop it
> entirely, or you can skip it when that distro feature is enabled, but
> don't expect outsiders to come and fix Yocto's internal CI issues,
> because _that_ is farcical.

That unit test was fixed back in November when this was last
discussed. 

The broken test was actually specific to usrmerge, showing how little
use this configuration actually gets in Yocto Project yet we're forcing
people onto it.

What still hasn't happened and what I mentioned above is the checks
around ensuring systemd can only be configured with usrmerge, the test
matrix updates to ensure we only test that configuration rather than
what we use right now which will no longer work, the recipe change to
enforce the distro feature and the documentation/migration information
that goes with those changes.

I'm frustrated that neither Yocto Project developers or systemd
developers seem to want to do this yet I know who will get the
complaints when things stop working or aren't documented :(.

Richard