Below are the steps to install the Nagios NRPE server on a Raspberry Pi. The configuration of the Nagios Server side are outside the scope of what we are trying to do here. This also assumes that you are running Raspbian on your Raspberry Pi.
First, we’ll want to make sure we have the latest cache of the repos.
sudo apt-get update
Next, we can go ahead and install the Nagios NRPE server on the Raspberry Pi:
sudo apt-get install nagios-nrpe-server
It will give you a list of dependencies it will install, and then ask you if you want to proceed. You can just type “y” and press ENTER.
Do you want to continue [Y/n]?
You’ll notice that it should have also installed a lot of the common Nagios plugins, which you’ll need for monitoring this host.
We will now want to configure the NRPE service. Go ahead and edit the config file using your preferred editor:
sudo vi /etc/nagios/nrpe.cfg
At a minimum, you’ll probably want to edit the “allowed_hosts” parameter, to include the IP of your Nagios Server.
Once the file is updated and saved, we’ll need to restart the NRPE service to read the changes.
sudo service nagios-nrpe-server restart
You should now be all set with NRPE running on the Raspberry Pi, and able to configure the Nagios Server to poll it for monitoring.