The NRPE addon is designed to allow you to execute Nagios plugins on remote Linux/Unix machines. The main reason for doing this is to allow Nagios to monitor “local” resources (like CPU load, memory usage, etc.) on remote machines. Since these public resources are not usually exposed to external machines, an agent like NRPE must be installed on the remote Linux/Unix machines.
Now I will advise you to explain the NRPE architecture on the basis of diagram shown below.
The NRPE addon consists of two pieces:
The check_nrpe plugin, which resides on the local monitoring machine.
The NRPE daemon, which runs on the remote Linux/Unix machine.
There is a SSL (Secure Socket Layer) connection between monitoring host and the remote host as shown in the diagram.
