[arch-general] RFC: OpenRC as init system for Arch

Patrick Lauer patrick at gentoo.org
Wed Apr 25 10:03:19 EDT 2012


in the last months there have been many discussions about init systems,
especially systemd. The current state seems to make no one really happy
- the current Arch Linux init system is a bit minimal and gets the job done, but it's not superawesome.
There's things like init script dependencies that would be nice to have, but then it's about the smallest of all init systems around.

On the other hand systemd is just Not The
Unix Way, it consolidates everything into one huge process and forces
some impossible dependencies (dbus? udev? on my server?! and you expect
a linux 3.0+ kernel? waaah!). But "everyone else" is moving to systemd,
so where does that leave us? (One might notice that "everyone else" is
just Fedora/RHEL at the moment, with (open)SuSE tagging along, and most
others still not committed to a migration yet)

As an alternative to the One Process For Everything I'd like to ask you to evalute OpenRC as an init system for Arch Linux.

While Gentoo is by far the largest user it's definitely not the only one
- there are the direct derivatives (Sabayon, pentoo, funtoo,
sysrescuecd, tinhat, ...) and some "foreign" users (Alpine, a debian
derivative, uses OpenRC)

What we offer you is a modern, slim, userfriendly init system with
minimal dependencies. All you need is a C99 compiler and a posix sh!
The list of features is long and tedious (see
http://wiki.gentoo.org/wiki/OpenRC ), but the critical bits are:

* portable - we have it running on Linux, *BSD, and there's no reason
why it should fail on other unixoid platforms
* dependency-based init scripts - no need to manually figure out the
startup order, something like "before apache, after logger" is all you
need to specify
* small footprint - 10k LoC C99, ~3k LoC Posix SH out of the box (plus
your own init scripts, of course)
* friendly responsive upstream (let's figure out how we can cooperate, eh?)
* boring - deterministic reproducable bootup, including interactive mode
and verbose debug output

For a long time we haven't done any active advertising, but OpenRC is
now about 5 years old, and it is a drop-in replacement for our previous
"baselayout" init system (which was started over a decade ago). We don't
try to take over the world, we just create the best solution for our
needs. And those go all the way from embedded systems (where you can use
busybox for all the shell tools) to servers (minimal deps! No mandatory
udev or dbus!) and desktops (including optional splash screen eyecandy
and whatever makes you happy).

There's pretty good support for advanced usage like SELinux, built-in
support for ulimit and cgroups to do per-service resource limits, and it
even comes with a friendly license (although some might say that a
2-clause BSD license it too friendly and promiscuous). And as a random
bonus feature you get stupid-fast bootup - We've seen <5sec from
bootloader handover to login prompt (depending on hardware and amount of
services started, of course) and <5sec for rebooting a kvm guest.

Should you decide to switch (or just evaluate if switching is possible /
makes sense) you'll get full support from us in migrating init scripts
and figuring out all the nontrivial changes. Just visit us on IRC (
#openrc on irc.freenode.net), send us a mail ( openrc at gentoo.org ) or
meet us for a beer or two.

Thanks for your consideration,

Patrick Lauer

Gentoo Developer, OpenRC co-maintainer

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