Nagios NRPE addon installation and configuration under Debian

Nagios is a service that, by default, runs on only one node. That host node can be used to check various services on other nodes - including SSH, ping, web services, and many others - but it can't execute commands on remote machines. In order to do that, you need to install the Nagios NRPE plugin, sometimes called the Nagios client. This plugin has two components: a simple plugin for Nagios on the host machine, and an NRPE daemon. The daemon needs to be installed on every machine than the host will be running remote commands on.

Installation on the Host Node

First, you'll need to install the NRPE plugin on the Nagios host node. This is the host that runs the web server and that you've already set up Nagios on. (If you haven't already set up Nagios, this tutorial will help you, and you should do that first.)

To install the host side of NRPE, issue

apt-get install nagios-nrpe-plugin

Installation on the Clients

Each one of the clients will need to have this installed and configured. On each machine that the Nagios host will contact to execute plugins remotely, issue 

apt-get install nagios-nrpe-server

• When prompted for Workgroup/Domain Name: enter your internal domain name
• When asked, Modify smb.conf to use WINS settings from DHCP?, keep the default of no

Depending on the version of Debian you're running, this may or may not install all of the default Nagios plugins. If you want them (if you're not just running your own custom plugins), install them with 

apt-get install nagios-plugins
 

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