Setting up Nagios monitoring server

Nagios is an open-source monitoring software, you can monitor different host resources like host UP/down status, disk usage, system load, logfile.
Setting up Nagios on Linux is very straight forward.

In our test environment, we will setup host centos as our monitoring host.

Steps to install Nagios on centos:
1. Download nagios core, nagios plugins
http://www.nagios.org/download/core, choose DIY option.
http://www.nagios.org/download/plugins, download latest stable version.

2. Create nagios account:

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

3. Install Nagios

# tar -zxpf nagios-3.5.0.tar.gz
# cd nagios
# ./configure --with-command-group=nagcmd
# make all
# make install

# make install-init
# make install-config
# make install-commandmode

# make install-webconf

4. Create nagiosadmin account, this account will be used to login to nagios web interface

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

5. Edit /etc/httpd/conf.d/nagios.conf, pointing AuthUserFile to /usr/local/nagios/etc/htpasswd.users

6. Start apache

# service httpd restart

7. Install Nagios Plugins

# tar -zxpf nagios-plugins-1.4.16.tar.gz
# cd nagios-plugins-1.4.16
# ./configure --with-nagios-user=nagios \
  --with-nagios-group=nagios
# make; make install

8. Enable autostart of Nagios and start Nagios service

# chkconfig --add nagios
# chkconfig nagios on
# service nagios start

9. Login to http://centos/nagios, you will see we already have centos monitored by Nagios

In the next post http://linuxscripter.blogspot.com/2013/09/using-nagios-and-nrpe-to-monitor-remote.html, I will discuss how to monitor remote hosts using Nagios and NRPE.

Reference: http://nagios.sourceforge.net/docs/3_0/quickstart-fedora.html