Re: using runit as init

[Bernhard Graf <list-supervision@augensalat.de>]

Vincent Danen wrote:

> You may also be interested in what Annvix has done.  Annvix has used
> runit for init for quite a few years now, and very successfully.  It
> still handles traditional "initscripts", but doesn't handle
> number-based runlevels or runlevel switching (largely due to the fact
> that Annvix has no GUI and thus has no real need for that).

Of course I also discovered Annvix already. Nice work (and a lot of, I 
suppose). Brought me to execline among other things, which I knew for 
quite some time, but never actually used so far.

> That's got the relevant runit scripts we use to handle init.  Note
> that we don't completely do away with sysvinit... there are some
> useful tools that come with it; we just don't use sysvinit's init.

Actually I'm missing two essential things in runit, that would allow to 
replace "standard" (Linux/SysV) init while keeping the start/Stop 
scripts in the beginning:

- possibility to set no-respawn mode for a service, instead run command
  (e.g. "/etc/init.d/service start") when service appears in runsvdir's
  directory and run other command (e.g. "/etc/init.d/service stop) when
  it disappears
- service dependencies

Another interesting project is ninit [1] and its ancestor minit [2]

[1] http://riemann.fmi.uni-sofia.bg/ninit/
[2] http://www.fefe.de/minit/

Those have dependencies and can start services w/o respawn, but they 
don't have a svscan-like function, they can start dependend services at 
start-up - later services must be brought up and down by [mn]svc 
command. Potentially this would fit better into an existing SysV-based
init scheme, because "/etc/init.d/service start" would just execute 
[mn]svc -u service and "/etc/init.d/service stop" [mn]svc -d service.

Still runit is much more elegant IMHO by starting and removing services 
as they appear and disappear - this would make runlevels really easy.
-- 
Bernhard Graf