Nagios server is an open source use for system monitoring, network monitoring and software application status. It gives your service alerts, information and status.
You know the server status immediately when problems occurred.

Installation steps:

You want to  install supporting packages in server

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

Create a user name nagios and set password,
#/usr/sbin/useradd -m nagios

# passwd nagios

Download the Nagios file using wget command,
# wget

Extract that file and configure it
# tar -xf nagios-4.0.3.tar.gz

# cd nagios-4.0.3


Web Interface Options:
                 HTML URL:  http://localhost/nagios/
                  CGI URL:  http://localhost/nagios/cgi-bin/

# make all

# make install

# make install-init

# make install-config

# make install-commandmode

# make install-webconf

Set nagios admin password for viewing on web interface
# htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin
New password:
Re-type new password:
Adding password for user nagiosadmin

Install plugin:

Download the files using wget command
# wget

Extract the tar.gz file and configure the plugin,
# tar xf nagios-plugins-1.5.tar.gz

# cd nagios-plugins-1.5

# ./configure --with-nagios-user=nagios --with-nagios-group=nagios

# #make && make install

To start Nagios  :
#/etc/init.d/nagios start
Starting nagios: done.

To stop Nagios :
#/etc/init.d/nagios stop
Stopping nagios: .done.

To restart Nagios:
# /etc/init.d/nagios restart
Running configuration check...done.
Stopping nagios: .done.
Starting nagios: done.

Start Apache server :
# /etc/init.d/httpd start
Starting httpd:                                            [  OK  ]
Nagios service will start during the system startup
# chkconfig nagios on
# chkconfig --list | grep nagios
nagios          0:off   1:off   2:on    3:on    4:on    5:on    6:off

If you will update any configuration in nagios check whether is it right?
# /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg

Now, Nagios Monitoring Web interface at : and give the user name and password

User Name: nagiosadmin (We have created the user name while configuring Nagios)

Click the  Gird view on Current Status.

We have to know the file usage and location,

Nagos host config File


Contacts File


Configuration file:


Resource File


Common Log:


Get Current status, comment, and Downtime Information


Object Cache File