NRPE (Nagios Remote Plugin Executor) is used for executing Nagios plugins on remote client systems. In previous article we had described about installation of Nagios Server on Ubuntu operating system. This article will help you to install NRPE on Ubuntu 15.04, 14.04, 12.04 & LinuxMint systems.

Step 1. Install NRPE and Nagios Plugins

NRPE is available under default apt repositories of Ubuntu systems. Execute the following command to install it

$ sudo apt-get install nagios-nrpe-server nagios-plugins

Step 2. Configure NRPE

In NRPE configuration, first we need to nrpe to which nagios servers it accepts requests, For example your nagios server ip is 192.168.1.100, then add this ip to allowed hosts list. Edit NRPE configuration file /etc/nagios/nrpe.cfg and make changes like

 allowed_hosts=127.0.0.1, 192.168.1.100

we can add more Nagios servers in allowed hosts by comma separated list.

Now restart NRPE service. Now its ready to listen requests from Nagios server

$ sudo /etc/init.d/nagios-nrpe-server restart

Let’s login to your Nagios server and verify that your Nagios server can communicate with NRPE service properly. Execute following command from nagios server plugin directory, and we are assuming that your nrpe client-server ip is 192.168.1.11.

# check_nrpe -H 192.168.1.11

NRPE v2.15

The output “NRPE v2.15” shows that nagios server successfully communicated with nrpe.

Step 3. Add Check Commands in NRPE

All the services check commands with the nagios plugins packages, which is by default installed in /usr/lib/nagios/plugins/ for 32 bit systems. Default installation adds few commands in configuration file. Add more commands as per your requirements like below

command[check_users]=/usr/lib/nagios/plugins/check_users -w 5 -c 10
command[check_load]=/usr/lib/nagios/plugins/check_load -w 15,10,5 -c 30,25,20
command[check_hda1]=/usr/lib/nagios/plugins/check_disk -w 20% -c 10% -p /dev/hda1
command[check_zombie_procs]=/usr/lib/nagios/plugins/check_procs -w 5 -c 10 -s Z
command[check_total_procs]=/usr/lib/nagios/plugins/check_procs -w 150 -c 200

Step 4. Start/Stop NRPE Service

Use following commands to start, stop or restart nrpe service. Each time we make any changes in configuration file required to restart service

$ sudo /etc/init.d/nagios-nrpe-server stop
$ sudo /etc/init.d/nagios-nrpe-server start
$ sudo /etc/init.d/nagios-nrpe-server restart