An introduction to Nagios monitoring

[Nitin(RHCE)]

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.