Question

How to install Nagios on CentOS?

Answer 1

Follow these steps:

Install the required packages

yum install httpd php php-cli gcc unzip wget glibc glibc-common gd gd-devel net-snmp

Start services

service httpd start

Set-up user accounts

useradd nagios
passwd nagios

Create a group for nagios and add nagios user to this group

groupadd nagcmd
usermod -a -G nagcmd nagios
usermod -a -G nagcmd apache

Install nagios core service

cd /opt/
wget https://assets.nagios.com/downloads/nagioscore/releases/nagios-4.4.3.tar.gz
tar xzf nagios-4.4.3.tar.gz
cd nagios-4.4.3
./configure --with-command-group=nagcmd
make all
make install
make install-init
make install-daemoninit
make install-config
make install-commandmode
make install-exfoliation

Set up Apache configuration

make install-webconf

Configure apache configuration

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

service httpd restart

Install Nagios plugin

cd /opt
wget http://nagios-plugins.org/download/nagios-plugins-2.2.1.tar.gz
tar xzf nagios-plugins-2.2.1.tar.gz
cd nagios-plugins-2.2.1

Compile and install Nagios plugin

./configure --with-nagios-user=nagios --with-nagios-group=nagios
make
make install

Start Nagios 

service nagios start

Access Nagios in a web browser 

http://nagios.tecadmin.net/nagios/