How to Install Nagios in Linux/CentOS server

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

Create Nagios User account and group
useradd -m nagios

Create nagcmd group for allowing external commands to be submitted through the web interface. Add both the nagios user and the apache user
groupadd nagcmd
usermod -a -G nagcmd nagios
usermod -a -G nagcmd apache

Create Directory to store Nagios installation files
mkdir /opt/Nagios
Download Nagios and Plugins

Save file to directory /opt/Nagios

http://www.nagios.org/download/download.php

Extract Files:
cd /opt/Nagios

tar xzf nagios-Currentversion.gz

cd nagios-Currentversion.gz

Compile and Configure Nagios
./configure –with-command-group=nagcmd
Compile Nagios:
make all
Compile binaries, init script, sample config files:

make install
make install-init
make install-config
make install-commandmode

** Do Not Start Nagios **
Nagios has now been installed to the directory /usr/local/nagios/
Install Nagios Web Interface:
make install-webconf
Nagios Web Interface installed to /usr/local/nagios/share ( http conf file added to /etc/httpd/conf.d/nagios.conf )

Create Web Interface Login User:
** This is not the most secure method **
We will create user “nagiosadmin” ( remember the password you assign !)

htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin
Restart Apache:
service httpd restart
Install Nagios Plugins

Extract Files:
cd /opt/Nagios
tar xzf nagios-plugins-1.4.13.tar.gz
cd nagios-plugins1.4.13
Compile and Configure Nagios Plugins
./configure –with-nagios-user=nagios –with-nagios-group=nagios

make
make install
Configure nagiosadmin email address for alerts
vi /usr/local/nagios/etc/objects/contacts.cfg

email [email protected];
Verify the sample Nagios configuration files
/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg

Total Warnings: 0
Total Errors: 0
Start Nagios

Enable Nagios to start at system startup / boot
chkconfig –add nagios
chkconfig nagios on
chkconfig httpd on
Start Nagios
service nagios start

Log into Web Interface

http://ip-address/nagios/