Installing Nagios core on RHEL / CENTOS 5.x – RHEL / CentOS 6.x Fedora 15/16/17/18/19/20

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What is Nagios

An enterprise-class monitoring and alerting solution that provides organizations with extended insight of their IT infrastructure before problems affect critical business processes.


We require following things for Installing Nagios:
These are Just Pre-requisites. We need them to other things work …

1. Apache and PhP (php is optional)
2. gcc, glib, glibc-common, gd and gd-devel

I am performing this whole task on RHEL 5 and nagios core.


( A ) Installing/checking Dependencies
As we know we get these repositories already installed, so let’s check whether they are installed or not!..

Its a major step so please don’t skip this

Invoke the terminal and write these command one by one:

1 To Check Apache/Http

rpm -qa | grep httpd

2. To Check the Gcc

rpm -qa | grep gcc
rpm -qa | grep glibc glibc-common
rpm -qa | grep gd gd-devel

If everythings come ok lets move ahead…if not install the package using

yum install httpd
yum install glibc glibc-common
yum install gd gd-devel
yum install httpd

( B ) Create User And Groups

We need to create a user Nagios and put it to group Nadmin

useradd -m Nagios
passwd Nagios
"Set the password for the user Nagios"

groupadd Nadmin

/usr/sbin/usermod -a -G Nadmin Nagios

/usr/sbin/usermod -a -G Nadmin apache

Building And Installing Nagios

Everything set lets begin with installation

1 Download Nagios tar using:

=> wget

2 Untar it anywhere 

=> tar zxf nagios-3.2.0.tar.gz

3 Get into the directory

=> cd nagios-3.2.0

4 configure the nagios using this command

=> ./configure --with-command-group=Nadmin

5 Run Make commands to build up the files to install Nagios

=> make all

6 Then use make install to install the init scripts in directory /etc/rc.d/init.d

=> make install

7 Lets configure permission for holding external files 

=> make install-init

8 Install sample config files which can be found later in /usr/local/Nagios/etc

=> make install-config

9 This for commandmode installation

=> make install-commandmode

10 Set your Email Id using:

=> vi /usr/local/Nagios/etc/objects/contacts.cfg

Installing Web Interface
After Nagios is Installed lets install the Web interface a key Utility

1 Install web interface

=> make install-webconf

2 Create web interface account. Using this we gonna login for management 

=> htpasswd -c /usr/local/Nagios/etc/htpasswd.users nagiosadmin

3 Done lets start Apache

=> /sbin/service httpd restart

As we are done with installing both Nagios and web interface we are yet not completed everything…

What we need now Nagios plugin , so lets begin with that :)

Installing and Configuring Nagios plugins

Download plugins by typing this command in the terminal

=> wget

Untar the file

=> tar zxf nagios-plugins-1.4.14.tar.gz

Change directory:

=> cd nagios-plugins-1.4.14

Lets configure it :)

=> ./configure --with-nagios-user=Nagios --with-nagios-group=Nadmin

Again make the files for the installation process

=> make

Install the plugins

=> make install

This is the second part of the Nagios installation Process

Now, we need to start the nagios

Here is the process for the same :

To make the nagios utility to work automatically use this:

=> /sbin/chkconfig --add nagios

Turn the Nagios on :)

=> /sbin/chkconfig nagios on

We need a check config file that can work for for auto start of nagios. To do that use 

=> /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg

Now start the service

/sbin/service nagios start

So here we are done with the nagios installation and configuration ….

For the web interface :
type the following in the URL

http://localhost/nagios orr http://ip/nagios

I tried to write this tutorial as simple as a 2nd standard guy can configure it 🙂  just a joke

any questions ??? let me know…..