2. Overview of this guide

What we will do is to configure few hosts to monitor. We will monitor specific services and health of those hosts. We will also add some networking equipment for monitoring. There will be also link state monitoring with notifications about link changes. Monitoring will be also applied to host and services, so you will get notifications about monitored hosts and services as well.

Monitoring in nagios is done in two steps. First we have to define service and hosts definitions. These definitions are called checks. For example you define that Windows hosts should have checks that include: C drive available space, free RAM, how many autostarted services are running (running services) etc. After that you have to define hosts types (groups) like Windows, Linux, Windows-vm etc. After that you have to link those definitions to specific hosts or groups. After that checks will performed and notifications to events/triggers might be configured.

What isn’t the most user friendly is that you have to do that all in command line. It is one of the limitations of the Core version. But it is FREE! To make things easier I add following line into sudo config located in(Debian) /etc/sudoers:


This enables specific user to execute root commands without entering root pass. Thanks to that you can use WinSCP in SCP mode and shell type: sudo su – (remember about “” at the end) to edit files in notepad2 or notepad++ instead of nano in terminal/shell. I found it very helpful and fast. I know it isn’t the most linux way and I should use nano or even vi but I prefer to make things easier :)