How to Install NRPE on CentOS and RHEL Systems

NRPE stands for Nagios Remote Plugin Executor, NRPE is designed to allow you to execute the Nagios plugins one remote Linux machines. It allows Nagios to monitor local host resources such as CPU statistics, Memory statistics, Disk Space etc on remote machine.

Follow the below link to install Nagios Server.

• How to Install Nagios Server on RHEL/CentOS and Fedora

Install NRPE on CentOS and RHEL

Follow the below steps to install NRPE on CentOS and RHEL.

Step #1 : Install EPEL Repository

First of all install EPEL repository on your system. It provides NRPE packages and plugins for Nagios. Follow the below link to install and enable the EPEL repository on the Linux system.

• How to Install EPEL Repository on RHEL/CentOS

Step #2 : Install NRPE and NRPE-Plugins

Now after installing and enabling EPEL repository, install NRPE and plugins on your system.

# yum --enablerepo=epel -y install nrpe nagios-plugins

You can also list of available commands packages and install in on your system using below command.

# yum --enablerepo=epel -y list nagios-plugins*

Installed Packages
nagios-plugins.x86_64                      2.2.1-4git.el7     @epel
Available Packages                                          
nagios-plugins-all.x86_64                  2.2.1-4git.el7     epel
nagios-plugins-apt.x86_64                  2.2.1-4git.el7     epel
nagios-plugins-bacula.x86_64               5.2.13-23.1.el7    base
nagios-plugins-bonding.x86_64              1.4-3.el7          epel
nagios-plugins-breeze.x86_64               2.2.1-4git.el7     epel
nagios-plugins-by_ssh.x86_64               2.2.1-4git.el7     epel
nagios-plugins-check-updates.x86_64        1.6.18-2.el7       epel
nagios-plugins-cluster.x86_64              2.2.1-4git.el7     epel
nagios-plugins-dbi.x86_64                  2.2.1-4git.el7     epel
nagios-plugins-dhcp.x86_64                 2.2.1-4git.el7     epel
nagios-plugins-dig.x86_64                  2.2.1-4git.el7     epel
nagios-plugins-disk.x86_64                 2.2.1-4git.el7     epel
nagios-plugins-disk_smb.x86_64             2.2.1-4git.el7     epel
nagios-plugins-dns.x86_64                  2.2.1-4git.el7     epel
.....
.....

Step #3 NRPE Configuration

After installing NRPE you need to edit its configuration file and start it.

# vim /etc/nagios/nrpe.cfg

Now add the below line with Nagios Server IP as shown below. In my case Nagios server IP is 192.168.0.5.

allowed_hosts=127.0.0.1, 192.168.0.5

Once edited the above file now lets see Nagios server is able to connect with NRPE client.

command[check_root_disk]=/usr/lib/nagios/plugins/check_disk -w 20% -c 10% -p /
command[check_load]=/usr/lib/nagios/plugins/check_load -w 15,10,5 -c 30,25,20

You can also add more commands like above as per requirement of monitoring.

Step #4 : Start NRPE Service

Now start and enable on boot the NRPE service after making all changes to apply the changes.

# systemctl enable nrpe.service
# systemctl start nrpe.service

Step #5 : Testing From Nagios Server

Now login to your Nagios server and execute the below command to verify that Nagios server is able to connect to client NRPE service. If it able to connect it will show version of clients NRPE package. In my case remote system IP is 192.168.0.6.

# check_nrpe -H 192.168.0.6
NRPE v3.1