[systemd-devel] How to get rid of this ordering cycle?

Simon McVittie simon.mcvittie at collabora.co.uk
Thu Aug 14 06:31:00 PDT 2014

On 14/08/14 13:27, Vlad Orlov wrote:
> # Provides:          mintsystem
> # Required-Start:    $local_fs $syslog $remote_fs dbus
> # Required-Stop:     $local_fs $syslog $remote_fs
> # Default-Start:     S
> # Default-Stop:  

As Lennart said, this is Debian-(and-its-derivatives)-specific: upstream
systemd does not support sysvinit services during early boot, i.e. rcS.

In Debian, support for sysvinit scripts in rcS was patched back in to
avoid breaking existing software, because it's unlikely that all of the
packages listed in
<http://codesearch.debian.net/search?q=Default-Start%3A\s*S> will get a
native systemd unit any time soon. Most of them probably doesn't
actually need to run in rcS - nvi? seriously? - but if fixing them all
was on the critical path for adopting systemd, we'd probably still be
using sysvinit for years to come.

Default-Start: S means basic-target.target depends on
mintsystem.service, which depends on dbus.service, which does not have
DefaultDependencies=no, so it implicitly depends on sysinit.target, so
you lose.

Or to put it in sysvinit terms, this is still incorrect: a service
started in rcS should not depend on dbus, which is started in rc2.

(Perhaps dbus should use DefaultDependencies=no - I think all it
actually needs are syslog.socket and /usr - but it has traditionally
been run in rc2.)

> I'd like to know: what can I change in this script to get rid of the ordering cycle?

You can start it later, in rc2 (so it can start after dbus.service); or
you can make it not depend on dbus if it doesn't actually need
dbus-daemon; or you can modify dbus.service to use
DefaultDependencies=no and declare its dependencies explicitly; or you
can delete it.

If mint-adjust.py is
then, ugh, this is the sort of thing that should not be done (and Debian
Policy specifically forbids it). Linux Mint should ship a patched
version of Debian's base-files package instead, like Ubuntu, SteamOS and
other Debian derivatives do: that's the correct place to declare your OS
to be a fork of Debian.


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