An introduction to Nagios monitoring

2006-06-01 00:00:00

Working at $CLIENT in 2005 was the first time that I built a complete monitoring infrastructure from the ground on up. In order to keep expenses low we went for a free, yet versatile monitoring tool: Nagios

Nagios, which is available over here, is a free and Open Source monitoring solution based on what was once known as NetSaint.

Nagios allows you to monitor a number of different platforms through the use of plugins which can run on both the server as well as on the monitoring clients. So far I've heard of clients being available for various UNIXen and BSDs (including Mac OS X) and Windows. Windows monitoring requires either the unclear NSClient software, or the NRPE_nt daemon which is basically a port of the UNIX Nagios client.

Setting up the basic server requires some fidgeting with compilers, dependencies and so on. However, a reasonably experienced sysadmin should be able to have the basic software up and running (and configured) in a day. However, adding all the monitors for all the clients is a matter entirely

Although there are a number of GUI's available which should make configuring Nagios a bit easier, I chose to do it all by hand. Just because that's what I'm used to and because I have little faith in GUI-generated config files. You will need to define each monitor separately for each host, so let's take a look at a quick example.

Say that you have twenty servers that need to be monitored by ten monitors each. Each definition in the configuration file takes up approximately sixteen lines, so in the end your config file will be at least 3200 lines long :)

But please don't let that deter you! Nagios is a powerful tool and can help you keep an eye on _a_lot_ of different things in your environment. I for one have become quite smitten with it.

In the menu you will find a configuration manual which I wrote for $CLIENT, as well as a bunch of plugins which were either modified or created for their environment. Quite possible there's one or two in there that will be interesting for you. tags: , , ,

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