Home » Categories » Multiple Categories

How To Create Nagios Plugins With Python On CentOS 6

This time, we will expand on this idea and create Nagios plugins using Python.

Step 1 - Install RPMForge Repository and NRPE

rpm -ivh http://pkgs.repoforge.org/rpmforge-release/rpmforge-release-0.5.3-1.el6.rf.x86_64.rpm
yum -y install python nagios-nrpe
useradd nrpe && chkconfig nrpe on

Step 2 - Create your Python Script

It would be a good idea to keep your plugins in same directory as other Nagios plugins (/usr/lib64/nagios/plugins/ for example). For our example, we will create a script that checks current disk usage by calling "df" from shell, and throw an alert if it is over 85% used:
import os, sys
used_space=os.popen("df -h / | grep -v Filesystem | awk '{print $5}'").readline().strip()

if used_space < "85%":
        print "OK - %s of disk space used." % used_space
elif used_space == "85%":
        print "WARNING - %s of disk space used." % used_space
elif used_space > "85%":
        print "CRITICAL - %s of disk space used." % used_space
        print "UKNOWN - %s of disk space used." % used_space

We will save this script in /usr/lib64/nagios/plugins/usedspace.py and make it executable:
chmod +x /usr/lib64/nagios/plugins/usedspace.py

The entire Nagios NRPE plugin boils down to using exit codes to trigger alerts.
You introduce your level of logic to the script, and if you want to trigger an alert (whether it is OK, WARNING, CRITICAL, or UNKNOWN) - you specify an exit code.
Refer to the following Nagios Exit Codes:

Nagios Exit Codes

Exit Code Status
0 OK

Step 3 - Add Your Script to NRPE configuration on client host

Delete original/etc/nagios/nrpe.cfgand add the following lines to it:


Where is our monitoring server from previous articles. Change these to your own values.
Make sure to restart Nagios NRPE service:
service nrpe restart

Step 4 - Add Your New Command to Nagios Checks on Nagios Monitoring Server

Define new command in/etc/nagios/objects/commands.cfg
define command{
        command_name    usedspace_python
        command_line    $USER1$/check_nrpe -H $HOSTADDRESS$ -c usedspace_python

As you can see, it uses NRPE to make TCP connections to port 5666 and run command 'usedspace_python', which we defined in /etc/nagios/nrpe.cfg on that remote host.
Add this check to your Nagios configuration file for client server.
For our example, we will monitor a server called MyCentOS and edit /etc/nagios/servers/MyCentOS.cfg
define service {
        use                             generic-service
        host_name                       MyCentOS
        service_description             Custom Disk Checker In Python
        check_command                   usedspace_python
Restart Nagios:
service nagios restart

Verify that the new check is working. And you are all done!
Attachments Attachments
There are no attachments for this article.
Related Articles RSS Feed
How To Set Up ProFTPD on CentOS 6
Viewed 1647 times since Thu, Jan 2, 2014
The Basics of Using the Sed Stream Editor to Manipulate Text in Linux
Viewed 1428 times since Fri, Dec 27, 2013
How To Install Wordpress on Centos 6
Viewed 1527 times since Tue, Dec 31, 2013
How To Create An Off-Site Backup Of Your Site With Rsync On Centos 6
Viewed 1605 times since Sat, Jan 4, 2014
How to Setup Additional Entropy for Cloud Servers Using Haveged
Viewed 1619 times since Sat, Jan 4, 2014
How To Deploy Node.js Applications Using Systemd and Nginx
Viewed 4820 times since Sat, Jan 4, 2014
How To Create Nagios Plugins With Bash On CentOS 6
Viewed 2014 times since Sat, Jan 4, 2014
How to Deploy Python WSGI Applications Using uWSGI Web Server with Nginx
Viewed 2082 times since Sat, Jan 4, 2014
How To Setup Your Own VPN With PPTP
Viewed 1548 times since Thu, Jan 2, 2014
How To Install Linux, Apache, MySQL, PHP (LAMP) stack On CentOS 6
Viewed 1750 times since Thu, Dec 26, 2013