Re: runit and System shutdown

[Henrik Heil <hhml@zweipol.net>]

Hi,

> i am using runit 1.0.5 on my Debian/Sarge for all the Daemons except
> postfix. runsvdir-start is run from inittab.

I have a similar setup on 2 servers and was wondering about the right 
way to do this.

> To me this sounds like total loss of control. Its quite a
> mess. Is there something i dont understand? Shouldnt there be an
> init-script that does runsvctrl d /var/services/* as the first Action
> in Runlevel 0?

In addition to the the shutdown of runsv, services and logservices in no 
particular order I recently noticed that with the default inittab-entry 
in runlevel 6:

* sendsigs TERM makes runsvdir exit immediatly, tells all processes to 
terminate an waits 5 seconds
* meanwhile SysV-init restarts runsvdir and runsvdir starts all services
* after 5 seconds all services are killed(-9) by sendsigs

I am using this inittab-entry for now:

RT1a:12345:respawn:/usr/sbin/runsvdir-start
RT1b:06:once:/usr/sbin/runsvdir-start

I am not shure about the shutdown-initscript. I was thinking in that 
direction but would like to use "svwaitdown -x -t 10 /var/services/*" 
because

* it waits for the services to actually stop.
* I believe it guarantees to stop the logservice after the service (is 
this correct?).

So an (untested) shutdown-script would be:

kill `pidof runsvdir`
svwaitdown -x -t 10 /var/services/*

(only works if runsvdir does not respawn -- see above)

Apart from the SysV-integration problem with the respawning runsvdir I 
think runit does the right thing when the commands receive a TERM signal:

If runsv receives a TERM it acts like runsvctl x.
If runsvdir receives a TERM signal, it exits with 0 immediately.

Even if you don't stop any services I believe it's unlikely that runsv 
tries to restart a service before it receives sendsigs TERM and itsself 
waits for the service to exit. So if you don't have somthing that takes 
more than 5 seconds to stop nothing too bad should happen.

But I am still not too familiar with process supervision an would really 
like to hear comments or a recommended way to stop runit under SysV-init 
from the experts.

Regards,
Henrik

-- 
Henrik Heil, zweipol Coy & Heil GbR
http://www.zweipol.net/