Installing Nagios 3.4.4 On CentOS 6.3

Introduction

Nagios is a monitoring tool under GPL licence. This tool lets you monitor servers, network hardware (switches, routers, ...) and applications. A lot of plugins are available and its big community makes Nagios the biggest open source monitoring tool. This tutorial shows how to install Nagios 3.4.4 on CentOS 6.3.

Prerequisites

After installing your CentOS server, you have to disable selinux & install some packages to make nagios work.

To disable selinux, open the file: /etc/selinux/config

# vi /etc/selinux/config

# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#     enforcing - SELinux security policy is enforced.
#     permissive - SELinux prints warnings instead of enforcing.
#     disabled - No SELinux policy is loaded.
SELINUX=permissive // change this value to disabled
# SELINUXTYPE= can take one of these two values:
#     targeted - Targeted processes are protected,
#     mls - Multi Level Security protection.
SELINUXTYPE=targeted 

Now, download all packages you need:

# yum install gd gd-devel httpd php gcc glibc glibc-common

Nagios Installation

Create a directory:

# mkdir /root/nagios

Navigate to this directory:

# cd /root/nagios

Download nagios-core & plugin:

# wget http://prdownloads.sourceforge.net/sourceforge/nagios/nagios-3.4.4.tar.gz
# wget http://prdownloads.sourceforge.net/sourceforge/nagiosplug/nagios-plugins-1.4.16.tar.gz

Untar nagios core:

# tar xvzf nagios-3.4.4.tar.gz

 Go to the nagios dir:

# cd nagios

Configure before make:

# ./configure

Make all necessary files for Nagios:

# make all

Installation:

# make install

# make install-init

# make install-commandmode

# make install-config

# make install-webconf

Create a password to log into the web interface:

# htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin

Start the service and start it on boot:

# chkconfig nagios on
# service nagios start

Now, you have to install the plugins:

# cd ..
# tar xvzf nagios-plugins-1.4.15.tar.gz
# cd nagios-plugins-1.4.15
# ./configure
# make
# make install

 Start the apache service and enable it on boot:

# service httpd start
# chkconfig httpd on

Now, connect to your nagios system:

http://Your-Nagios-IP/nagios and enter login : nagiosadmin & password you have chosen above.

And after the installation ?

After the installation you have to configure all your host & services in nagios configuration files.This step is performed in command line and is complicated, so I recommand to install tool like Centreon, that is a beautiful front-end to add you host & services.

To go further, I recommend you to read my article on Nagios & Centreon monitoring.