Basic setup

aptitude install nagios-nrpe-server

/etc/nagios/nrpe.cfg 

allowed_hosts=127.0.0.1,nagios.panelnet.cz,88.86.101.28
command[check_root]=/usr/lib/nagios/plugins/check_disk -w 20% -c 10% -p /dev/md0
command[check_data]=/usr/lib/nagios/plugins/check_disk -w 20% -c 10% -p /dev/md5

test

/usr/lib/nagios/plugins/check_nrpe -H ets.panelnet.cz -c check_data