Re: starting service order

[Marco Ermini]

<quota chi="Sebastien ESTIENNE">
> Hello,
> I'm in the process to integrate monit in linux gentoo as the default way
to handle system services.
</quota>

I don't think it's a clever idea. For what I could see, Monit is best
suited as a kind of alarming system for a specific setup, not as a generic
system startup service.

I think you could, at least, "assist" a system V/rc script startup system
with monit, but not replace entirely.


<quota chi="Sebastien ESTIENNE">
> I wanted to know if it was possible to define the order in which the
services will start. for example mysql before apache. I think it's
different from dependencies because sometimes only the order is
important.
</quota>

Sure it is, but it's not possibile, by now, with monit. Or, it's not
_explicitely_ possibile - I think Monit just follows the order you write
in monitrc :-)

It's different, because maybe you want to start apache even if mysql fails
- there are cases in which it could be acceptable to serve just static
pages, for instance - so dependencies are not weel suited to provide a
startup order.

Dependancies in Monit are a kind of "closer" relationship compared to a
system V's or rc script's startup system: the apache which depends by
mysql it's not a "default" or "generic" apache, it's a _specific_ and
_customized_ application deployed to work _only_ with mysql - it's a
no-sense to start apache if mysql is broken.


> Maybe it could be implemented using dependency, if we could define that
some dependency can fail.
> thanks for your answers

In my 5 cent worth opinion, Monit is very good to be customized for
specifical setups and specifical application monitoring, but I don't think
it's well suited for a generic distro startup system. This would require a
lot of work in my opinion.

To provide such a service, you should define:

1) the ability for a dependency to fail
2) a kind of ordering, or at least, the ability to not startup the
subsequent service in the list if the previous did not already completed
to startup _without_ using a dependency
3) some tool to easily rearrange the services (a chkconfig-like tool) 4)
the ability tu support different runlevels


My 5 cent worth


Regards
-- 
Marco Ermini
http://www.markoer.org
Dubium sapientiae initium. (Descartes)
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