[systemd-devel] [HEADS-UP] Early-boot SysV service support is going away

[Lennart Poettering]

Heya,

In a month or two we'll make the SysV service logic in systemd
generator-based. This helps us clean up our codebase a bit and makes
SysV service support an optional plugin rather than something that is
built into PID1.

Effectively, by doing this move very little will change in behaviour for
SysV scripts, with one exception however: we will remove support for
early-boot SysV scripts. Early-boot SysV scripts are those for the
special "S", "boot", or "b" runlevel that exist on some distributions.
These runlevels are highly distro specific, have never been really
standardized and are really cumbersome to support right now with a lot
of per-distribution hacks.

Please do not misunderstand this: it's one thing supporting normal SysV
scripts, it's another one supporting them in the early boot part of the
things. The former is going to stay for a long time, the latter however
is going to be removed in a couple of month.

Anyway, this is basically just a heads-up about this, so that you folks
who still need this can think about good solutions what to do
instead. Here's what I can propose:

a) port the early-boot init scripts to native systemd units. You
probably should do that anyway, and in most cases there should be very
little left that systemd doesn't do on its own anyway in the early-boot
process. We recommend to go this way, of course.

or 

b) Try to forward-port support for these magic runlvels to what's
coming. Probably a lot of work, since due to the conversion to a
generator this is a lot more work than it might appear right now. The
code structure of the sysv logic will change quite substantially.

or 

c) write an explicit generator for these services, in the specific
syntax of your distro. 

Anyway, please think about it, we'd just like to make you aware of this
in time.

At least Debian, Suse, Ubuntu, Angstrom appear to be candidates where
this lost functionality might be noticable.

Lennart

-- 
Lennart Poettering - Red Hat, Inc.