How to Install Nagios 4.0.8 on CentOS 6.5

Install the prerequisite packages

yum install gd gd-devel httpd php gcc glibc glibc-common make perl wget

If you want to monitor SNMP you should install net-snmp now

yum install net-snmp net-snmp-utils
service snmpd start
chkconfig snmpd on

Create the Nagios user.

useradd -m nagios
passwd nagios
groupadd nagcmd
usermod -a -G nagcmd nagios
usermod -a -G nagcmd apache

Create a directory to download and build Nagios from

mkdir /root/nagios
cd /root/nagios

Download Nagios and the Nagios plugins


Extract the Nagios zip

tar xvzf nagios-4.0.8.tar.gz
cd nagios-4.0.8

Compile and make it

make all
make install
make install-init
make install-commandmode
make install-config
make install-webconf

Create a password so you can login to the web interface

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

Enable Nagios on startup

 chkconfig nagios on

Start the service

service nagios start

Install the plugins.

cd ..
tar xvzf nagios-plugins-2.0.2.tar.gz
cd nagios-plugins-2.0.2
make install

Start apache and make sure it starts on boot.

service httpd start
chkconfig httpd on

You should now be able to access Nagios by going to https://nagiosserverip/nagios

If you run into issues check your firewall and make sure SELinux is disabled.