Nagios

Nagios is a powerful monitoring system that enables organizations to identify and resolve IT infrastructure problems before they affect critical business processes.

Check command

/usr/local/nagios/libexec/check_nrpe -H 192.168.1.1 -c check_metric

Sample /etc/nagios/nrpe config file on CentOS 6.3 64 bit, host checked by Nagios

log_facility=daemon
pid_file=/var/run/nrpe/nrpe.pid
server_port=5666
nrpe_user=nrpe
nrpe_group=nrpe
#nagios server 192.168.1.2
allowed_hosts=196.168.1.2,127.0.0.1
dont_blame_nrpe=0
debug=1
command_timeout=60
connection_timeout=300
include_dir=/etc/nrpe.d/

command[check_users]=/usr/lib64/nagios/plugins/check_users -w 5 -c 10
command[check_load]=/usr/lib64/nagios/plugins/check_load -w 15,10,5 -c 30,25,20
command[check_hda1]=/usr/lib64/nagios/plugins/check_disk -w 20% -c 10% -p /dev/hda1
command[check_zombie_procs]=/usr/lib64/nagios/plugins/check_procs -w 5 -c 10 -s Z
command[check_total_procs]=/usr/lib64/nagios/plugins/check_procs -w 150 -c 200

check_oracle_health shows warning when OK

http://forums.meulie.net/viewtopic.php?f=62&t=6282

Nagios shows Warning when is OK

Run the command locally on the target server with the user nrpe

su nrpe
mycommand.py
echo $?

If there are problems of permissions or similar wqhen running with the user nrpe solve them Always test the commands under the user nrpe.

If the command creates or uses files, delete them if the command tested with root, so they are created properly with the right permissions.