What is it?

Nagios is a fantastic F/OSS project that provides an entire, flexible, monitoring infrastructure for your network, services, and machines. The full suite of capabilities is better explained in Nagios’ own documentation, But the main thing that sets nagios apart is its very simple idea of a check plugin. In nagios, any type of service check can be added simply be writing a small script that returns 0,1,2, or 3 when it exits to inidcate the state of the monitored service.

Nagios itself comes with a number of excellent general purpose checks (port checks, process checks, etc), and there is a plugins project that provides its own extended collection of plugins. Over the years I (along with a few of my colleagues) have needed to add a few of our own checks. Not all of them conform to the same development standards, and they are likely riddled with bugs – but they have solved monitoring problems for us in the past.

Get it

The Nagios plugins can be gotten here as a tarball.