In this recipe, we'll follow a procedure to find a plugin appropriate to a specific monitoring task. We'll start by checking whether an existing plugin is already available to do just what we need. If we can't find one, we'll check whether we can use another more generic plugin to solve the problem. If we still find that nothing suits, we'll visit Nagios Exchange and search for an appropriate plugin.
You should have a Nagios Core 4.0 or newer server running with a few hosts and services that are configured already, and you'll need to have a particular service on one of these hosts, which you're not yet sure you need to monitor.
We'll use a simple problem as an example; we have a server named
troy.example.net that runs an
rsync(1) process that listens on port
873. We're already monitoring the host's network connectivity via PING, but we'd like to have Nagios Core check whether the
rsync(1) server is available and listening at all times, in case it crashes while...