Writing a custom init script

It's been a long time since I did a source tar-ball install. But the production servers at work require that applications that are not part of the standard install base (from Kickstart/Jumpstart and VMWare images) should be compiled from source. It was a very refreshing experience. :)

So after going through the usual configure; make; make install invocation, it was time to make sure that the app is persistent at boot. I would have copied an init script from my *nix desktop, but good thing SLES had a baseline script in /etc/init.d/skeleton.

In a nutshell, the steps are:

1. Define the INIT INFO section, as per the LSB specs.


2. Fill in the variables.


3. Use /etc/rc.status and rc_* functions for sanity checks.


4. Create the basic start, stop and status functions.


5. Use YAST (System > System Services (Runlevel)) -- or, if available, innserv -- to enable the startup script.

Below is a script I wrote for Apache:

#!/bin/sh
#
# Author: Ian Dexter R. Marquez
#
# /etc/init.d/httpd
#
### BEGIN INIT INFO
# Provides: httpd
# Required-Start: $local_fs
# Required-Stop: $local_fs
# Default-Start: 3 5
# Default-Stop: 0 1 2 6
# Description: Start the Apache httpd daemon
### END INIT INFO

HTTPD=/path/to/apache/2.2.4/bin/httpd
APACHECTL=/path/to/apache/2.2.4/bin/apachectl
PROG=httpd

test -x $HTTPD || exit 5
test -s /etc/rc.status && . /etc/rc.status && rc_reset

start() {
   echo -n "Starting $PROG: "
   $HTTPD -k start
   rc_status -v
}

stop() {
   echo -n "Stopping $PROG: "
   /sbin/killproc $HTTPD
   rc_status -v
}

status() {
   echo -n "Checking $PROG: pid "
   /sbin/pidofproc $HTTPD
   rc_status -v
}

case "$1" in
   start)
      start
      ;;
   stop)
      stop
      ;;
   restart)
      stop
      start
      rc_status
      ;;
   status)
      status
      ;;
   try-restart|condrestart)
      if test "$1" = "condrestart"; then
         echo "${attn} Use try-restart ${done}(LSB)${attn} rather than condrestart ${warn}(RH)${norm}"
      fi
      $0 status
      if test $? = 0; then
         $0 restart
      else
         rc_reset   # Not running is not a failure.
      fi
      # Remember status and be quiet
      rc_status
      ;;
   graceful|help|configtest|fullstatus)
      $APACHECTL $@
      rc_status
      ;;
   *)
      echo "Usage: $PROG {start|stop|restart|status|graceful|help|configtest|fullstatus}"
      exit 1
esac
rc_exit

References:

• Writing Init Scripts, Novell Developer Net.


• Creating Custom Init Scripts, Novell Cool Solutions.