Nagios – Centos

I will give some info on the deployment of Nagios the Monitoring software (Can monitor Windows or Linux).


Installation Key Points:

  •  Install CentOS from net Install – Version 5.5 (

Nagios Installation Key Points

After you installed the system log in as root and run update the system:

yum update

If the kernel was updated reboot the system.



Now we have to include the rpmforge repository to install Nagios 3.0.x.
If you are not familiar with installing repostiorys using yum read this.

yum install yum-priorities


Install RPMForge


Now install the Nagios software:

yum install nagios nagios-plugins nagios-devel nagios-plugins-nrpe


You need to disable SELinux if you want to start nagios or you have to modify the configuration of SELinux. I will only explain the easier way to disable SELinux.



set the SELinux to warn or disabled.

Allow http traffic to you machine:



Set the nagiosadmin password:

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


The username has to be nagiosadmin otherwise you will not have accessrights.

Add Nagios to your runlevels:

chkconfig –levels 35 nagios on


Add httpd to your runlevels:


chkconfig –levels 35 httpd on

Start the two services:

service httpd start

service nagios start


Connect to your Nagios Interface:



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