Nagios NRPE Installation

In previous article, we learn how to install nagios (monitoring tool). Now we'll learn how to install nagios agent on the system, which needs to be monitored in nagios. This Agent tool is known as Nagios NRPE (for linux). To monitor system having Windows operating system, we need to install NSClient++. NSClient++ is very easy to install as it is simply a .exe file. Here are the steps to install NRPE plugin (agent) on linux machine:

• Install required packages

yum install gcc
yum install openssl-devel

• Create Installation directory

mkdir /install

• Download NRPE

wget ​http://prdownloads.sourceforge.net/sourceforge/nagios/nrpe-2.12.tar.gz
tar -zxvf nrpe-2.12.tar.gz
cd nrpe-2.12
./configure

• Execute Commands

make all
useradd nagios
make install
cd /install

• Download & Install Nagios-Plugin

wget ​http://prdownloads.sourceforge.net/sourceforge/nagiosplug/nagios-plugins-1.4.16.tar.gz
tar -zxvf nagios-plugins-1.4.14.tar.gz
cd nagios-plugins-1.4.14
./configure
make all
make install

• Install NRPE into /etc/init.d

chmod a+x nrpe

• Backup of Nagios installation

cd /usr/local/
cp -frp nagios/ nagios_/ 

• Configuration for another server in nagios.cfg

These configurations has to be done on server, where Nagios server is installed.
cd /usr/local/nagios/etc/
vi nagios.cfg 

Add below lines to add an entry for another server to be monitored.
# Definitions for monitoring the local (Linux) host
cfg_file=/usr/local/nagios/etc/objects/server96.cfg

• Add Configuration file for another server

cd objects/
cp -rf /usr/local/nagios/etc/objects/localhost.cfg /usr/local/nagios/etc/objects/server96.cfg
chown -R nagios:nagios server96.cfg
vi server96.cfg and made the needful changes.

• Restart the services

service nagios restart
service httpd restart