What is Nagios?
Nagios is a powerful monitoring system that enables organizations to identify and resolve IT infrastructure problems before they affect critical business processes.
It has the capability of monitoring application, services, entire IT infrastructure. It has been designed with scalability and flexibility in mind, Nagios gives you the peace of mind that comes from knowing your organization’s business processes won’t be affected by unknown outages.
Nagios is a one of the best open source tools available in the market that provides you with instant awareness of your organization’s mission-critical IT infrastructure. Nagios allows you to detect and repair problems and mitigate future issues before they affect end-users and customers.
Step 1: Install Dependencies and Required Packages
We are assuming that you have fresh installed CentOS, Red hat or Fedora systems, So our first requirement is to install LAMP . You have not installed LAMP server, Please click here for LAMP installation steps or Click on the below link.
# yum install httpd php php-cli gcc glibc glibc-common gd gd-devel net-snmp
# service httpd start
Step 2: Create User Accounts
Now create a new nagios user account and setup a password to this account
# useradd nagios
# passwd nagios
Now create a groud for nagios setup “nagcmd” and add nagios user to this group. Also add nagios user in apache group.
# groupadd nagcmd
# usermod -a -G nagcmd nagios
# usermod -a -G nagcmd apache
Step 3: Install Core Service
After installing required dependencies and adding user accounts. Lets start with Nagios core installation. Download latest nagios core service from official site.
# cd /opt/
# wget http://prdownloads.sourceforge.net/sourceforge/nagios/nagios-4.0.8.tar.gz
# tar xzf nagios-4.0.8.tar.gz
# cd nagios-4.0.8
# ./configure –with-command-group=nagcmd
# make all
# make install
# make install-init
# make install-config
# make install-commandmode
Now use below command to setup apache configuration for Nagios installation.
# make install-webconf
Step 4: Configure Apache Authentication
We need to setup apache authentication for user nagiosadmin. Do not change this username. else you would required more changes in configuration.
# htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin
Now restart Apache service to make the new settings take effect.
# service httpd restart
Step 5: Install Nagios Plugins
After installing and configuring Nagios core service, Download latest nagios-plugins source and install using following commands.
# cd /opt
# wget http://nagios-plugins.org/download/nagios-plugins-2.0.3.tar.gz
# tar xzf nagios-plugins-2.0.3.tar.gz
# cd nagios-plugins-2.0.3
Now compile and install nagios plugins
# ./configure –with-nagios-user=nagios –with-nagios-group=nagios
# make install
Step 6: Verify and Start Nagios
Use the following commands to verify nagios install and start nagios core service.
# /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
# service nagios start
Also configure nagios service to start on system start
# chkconfig –add nagios
# chkconfig nagios on
Step 7: Access Nagios in Web Browser
Nagios creates its own apache configuration file /etc/httpd/conf.d/nagios.conf. There are no need to make any changes to it. Simply open below url in browser.
[change your domain or ip]
Login with new created login credential.
Now you have successfully installed and configured Nagios core service in your system.