Re: starting service order

[Sebastien ESTIENNE]

> To provide such a service, you should define:
>
> 1) the ability for a dependency to fail
>  
Yes that's i was asking if this feature exist, it could be implemented 
like this

depends on apache_bin can fail 
or a new keyword that would do the same thing named "before"


> 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
>  
it could be implemented by keywords like before/after
Gentoo linux already provide this functionnality (look here: 
http://www.gentoo.org/doc/en/handbook/handbook-x86.xml?part=2&chap=5#doc_chap4 
)
you can define order with before after
dependencies need/use and also provide

for example you can say that qmail "provide mta" and "need  net"
and that nagios "need mta"

so the system knows that he must start qmail before nagios (if you had 
use the "use" keyword instead of "need" it means that qmail can fail 
it's okà

"provide" is also because you can say that many service provide the same 
functionnality, eg: mta -> qmail, postfix, exim

> 3) some tool to easily rearrange the services (a chkconfig-like tool) 4)
> the ability tu support different runlevels
>  
I wrote this tool, it was easy, i just modified the default tool from 
gentoo (it was just a matter of 5 lines)
I did it like this:
in /etc/monitrc i added  "include /etc/monit.d/autostart/*"
in /etc/monit.d/ i put a file by service (eg: apache postfix mysql)
and the tool just write or remove a link from /etc/monit.d/ in 
/etc/monit.d/autostart
so i have the exact same functionnality as a tool like chkconfig
(i don't know if you use gentoo, but now i add services like this: 
rc-update add apache monit)

you said that monit is only good in specialized situation, or when 
customized, it's true, but you can define default and then allow the 
user to provide custom settings without modifying the default install, 
using include:
the default, would only check for pid, and listening port and then the 
user can overide things or adding things by including his configuration:
eg:
/etc/monit.d/system/SERVICE <- contain all default service config
and each SERVICE contain a line like this at the end: include 
/etc/monit.d/user/SERVICE
so when a user want to customized apache for example, he just have to 
create a file /etc/monit.d/user/apache

I think that monit can remplace the default system, because the onlyt 
things that the default init system has to do, is stating/stopping 
system in the right order nothing more
and i don't see why monit couldn't do this?
for example djb's daemontools where built to manage services (they 
manage qmail/djbdns) and monit seems to be a daemontools++. too bad he 
also missed the ability to define services start order...

--
Sebastien ESTIENNE
Administrateur Système et Réseaux
www.ovibes.net