Monitoring Fedora servers with NAGIOS

By | February 7, 2015

This is a description of the installation process of NAGIOS monitoring on two Fedora21 based servers.

Choose one server as the main nagios host. Lets call it nas1.

Add nagios users , group and add apache as member in the nagios group:

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

Install nagios binaries on nas1:

# yum install -y nagios

Install all the nagios plugins on nas1:

# yum install -y nagios-*

Start nagios service and enable it at server start.

# systemctl start nagios
# systemctl enable nagios

Change the default password for nagiosadmin user. This will be the user used to login to the nagios web interface.

# htpasswd -C /etc/nagios/passwd nagiosadmin

Restart the Apache service.

# systemctl restart httpd

To access the nagios web interface simply point your browser to https://nas1/nagios

Add a second linux host nas2 to Nagios monitoring server nas1 using the NRPE Plugin.

First do on nas2 the following installation steps:

Add nagios users , group and add apache as member in the nagios group:

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

Install nagios binaries on nas1:

# yum install -y nagios

Install all the nagios plugins on nas1:

# yum install -y nagios-*

Start nagios service and enable it at server start.

# systemctl start nagios
# systemctl enable nagios

Edit the nrpe config file

# vi /etc/nagios/nrpe.cfg

Change the following from default to:

  • allowed_hosts=nas1

Start the nrpe daemon and enable at server start.

# systemctl start nrpe
# systemctl enable nrpe

Check the status of nrpe to see the port and allowed hosts

# systemctl status nrpe

In case a firewall is active on nas2 add a rule:

# iptables -A INPUT -p tcp -m tcp –dport 5666 -j ACCEPT
# service iptables save

On the Nagios monitoring server nas1 we already have installed the nrpe plugin the remaining steps are:

  • Create a Nagios command definition using the check_nrpe plugin.
  • Create Nagios host and add service definitions for monitoring the remote Linux host.

TO BE CONTINUED …

 

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