3.5.1 Matrix Server Administration Guide

Chapter 17: Advanced Monitor Topics 271

• For a service monitor, the file must be installed on each server

associated with the virtual host on which the service monitor is

located.

• For a device monitor, the file must be installed on each server that is

configured with the virtual hosts associated with the device monitor.

• The command termination exit status is used to signal script success

or failure. A 0 (zero) exit status indicates script success; any other exit

status indicates script failure.

Types of Custom Scripts

You can develop the following types of custom scripts for use with

service and device monitors.

Probe Scripts

Probe scripts run periodically and check the health of a service or device.

You will need to determine what the probe should look at and how it

should exit.

For example, you might want to create a custom service monitor for an

application that creates a pid file when it is running. You could write a

shell script called /usr/local/myprobes/testpid that looks up the pid from

the application’s pid file and then determines whether the pid is actually

running.

Here is the testpid script:

if [ ! -e $1 ]; then # Does the pid file exist?

exit 1

read pid < $1 # Read the pid into the variable pid

kill -0 $pid # Does the pid exist in the process table?

When you create the service monitor, you would specify the following as

the user probe script. (Specifying the application’s pid file as a parameter

instead of naming it in the script allows the testpid script to be used with

any application that creates a pid file.)

usr/local/myprobes/testpid /var/run/application.pid