[systemd-devel] [packaging] split of systemd package

[Zbigniew Jędrzejewski-Szmek]

On Wed, Nov 11, 2015 at 12:58:14PM +0100, Martin Pitt wrote:
> Hello all,
> 
> in case it's useful, this is how we split them in Debian.
> 
> However, is this even a topic for upstream, apart from giving
> recommendations? I. e. do you actually consider putting this kind of
> split into the upstream build system à la "make install-<component>"?
> 
> Lukáš Nykrýn [2015-11-11 11:47 +0100]:
> > Personally I don't think it makes sense to split the package to get a
> > smaller core package. Most of our binaries are just few KBs.
> 
> They are actually fairly big, 100 kB to 1.5 MB for systemd itself. I
> think the main reason for that is that they all statically link
> libsystemd instead of dynamically linking to libsystemd.so.0. Is there
> a particular reason for that?
> 
> > Other aspect would be minimizing external dependencies.
> 
> That is one important reason why we split them in Debian; e. g. the
> machined/nspawn/importd group pulls in a number of rather heavy
> dependencies. udev (including hwdb) is something which you don't need
> in containers, so we split that out too.
> 
> Another reason is to make it easy to enable/disable a particular
> feature (e. g.  libnss-myhostname).
> 
> And then of course the infamous "need to run with sysvinit/upstart",
> which other distros don't need to be concerned about :-)
> 
> > So I suggest following scheme
> 
> FTR, this isn't too far away what we already do in Debian/Ubuntu:
> 
> > systemd
> 
> check
> 
> > systemd-libs
> > systemd-devel
> 
> They are called a bit differently for distro policy, upgrade safety,
> consistency, and multi-arch support reasons; we need separate binary
> packages for every lib*.so. But in spirit, "check".
> 
> > systemd-journal-remote (so gatewayd,remote,upload)
> 
> Check, we have exactly this package name.
> 
> > systemd-networkd (maybe also with resolved?)
> 
> We currently keep that in the "systemd" package as splitting it out
> now is a bit of an upgrade pain, but we discussed doing this.
> 
> > systemd-machine (machined,nspawn,importd)
> 
> We call that package "systemd-container", but it has exactly those, so
> "check".
> 
> > systemd-firstboot (firstboot,sysusers?,factory stuff?)
> 
> We don't have a separate package for that.
> 
> > systemd-hwdb
> 
> We split out the entire udev, including hwdb. This nicely reduces the
> footprint in containers and also allows us to use udev with
> sysvinit/upstart.

Yeah, after removing a bunch of stuff, hwdb stuff becomes even more
pronounced.

I prepared a package for rawhide with [1,2] the following subpackages:
systemd-journal-remote (remote, upload, gatewayd)
systemd-container (nspawn, machinectl, machined, importd, pull, var-lib-machines.mount)
systemd-udev (udevd, udevadm, udev rules, hwdb).

The first two are uncontroversial (systemd-journal-remote already existed
as systemd-journal-gateway for a long time).
The last is somewhat controversial: while people seem to agree about the split,
it's not necessary clear whether udevd should be in the subpackage or not.
I went with "yes", to see how that works out. I think this makes more
sense this way, but maybe not.

[1] http://in.waw.pl/git/fedora-systemd/
[2] https://copr.fedoraproject.org/coprs/zbyszek/systemd/build/138959/