Re: OpenRC now supports daemon supervision using s6

From: Steve Litt <>
Date: Sun, 26 Jul 2015 14:34:13 -0400

On Sun, 26 Jul 2015 12:51:48 +0200
Laurent Bercot <> wrote:

> On 26/07/2015 04:35, Steve Litt wrote:
> > For all I know it might amelliorate the other problem: insane init
> > script complexity, by putting more of the details in the s6 run
> > script.
> I'm not sure that would be a good trade-off. An init script is run
> once at boot time - or whenever you're changing the machine state -
> whereas a ./run script is run every time the service starts, i.e at
> least as often. Better move as much complexity as you can *outside*
> the run script.
> > Me, I'd just go with s6 out of the box, but I guess OpenRC is more
> > corporationally correct or something like that
> What OpenRC does and s6 alone does not is dependency management,
> which is important for heavyset services (including, I guess, desktop
> setups). A supervision suite does not handle dependencies between
> oneshot services and longrun services, and only implicitly handles
> dependencies between longrun services (by letting them restart until
> everything works). A real dependency-based systems starts services
> in the order they are needed, which is all in all a good thing.

s6 + LittKit!

> If you want to test a supervision suite + dependency management
> system combo doing the right thing, try out anopa, or the publically
> available preliminary version of s6-rc. ;)

I might do that. Suckless Init plus s6 plus LittKit worked well for me,
but LittKit requires *me* to know enough to know what order things
should start in, and requires *me* to make up tests to make sure that
process are ready, or that tasks have been completed.

> > it can use s6 to do the supervision (and sysvinit to do the PID1,
> > you can't make this up, folks).
> OpenRC runs s6-svscan as one of its services, so it can't use it as
> init - so it needs to run under another init.
> But that's not such a big deal. When switching "init systems", the
> rc subsystem is really the difficult part. Once you have a working rc
> system, it's not too hard to switch pid 1.

Weeeelll, depending on how separable they are. If you swap out
systemd's PID1 for Suckless Init, I'll be surprised :-)

Hey, seriously, congratulations on s6-rc. If it's what I think it is,
it's a sorely needed thing.


Steve Litt
July 2015 featured book: Rapid Learning for the 21st Century
Received on Sun Jul 26 2015 - 18:34:13 UTC

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