Requisite for starting sevices in rh9

tuxfood · 05-17-2005, 05:36 AM

Hi ..

I am trying to figure out the dependencies between the services in my system i.e,
which all services to start before a particular service can be started.

For example ... vsftpd requires network.
netfs reuires network
some services require xinetd to be enabled before using them

I have read thru the /etc/rc.d/init.d scripts and have found out that most of the scripts just check for some service having enabled thru checking some variable..

eg : most of the scripts check whether network is up by checking the variable

NETWORKING which is declared in /etc/sysconfig/network.

Other scripts just assume the service has started by included the above file in the startup script.

How can we be sure whether any other service must have started before a particular service can be started. (of course apart from the trial and error method).

Any ideas ???

thnks

tuxfood

cormander · 05-17-2005, 10:06 PM

If the service runs as a daemon, you can see if it is running with the "pidof" command. If it returns nothing, the service is not running. Otherwise, it gives you the pid(s) of the process(es) running.

For example:

pidof httpd
15973 15938 5291 26219 26212 18519 14400 24442 24441 24317 21207 17957 17955 17954 17953 7161 18977 18797

That is the master process and all of it's children running.

/sbin/pidof asgasg

That returns nothing, naturally, because asgasg doesn't even exist, much less is running.

In bash, you can do something like this in a script:

Code:

#!/bin/bash

if [ -z "$(/sbin/pidof httpd)" ]; then

    echo "httpd is not running"

else

    echo "httpd is running"

fi

Hope this helps.

tuxfood · 05-19-2005, 01:52 AM

hi..

what i actually want is to find out which all services should be up before a particular service can be started

eg: vsftpd can be started only if network is up
httpd can be started only if network is up

etc

i hope i make myself clear

thnks
tuxfood