I was surprised that nagios plugins didn’t come with a pre-packaged check_crond command! Anyway, here is a quick way to do it using NRPE.
Add the command definition in command.cfg.
define command{ command_name check_crond command_line $USER1$/check_nrpe -n -H $HOSTADDRESS$ -t 90 -c check_crond }
Add the service definition to an existing host.
define service{ use local-service host_name gnucom.cc service_description CROND check_command check_crond notifications_enabled 1 }
And last but not least the /usr/local/nagios/nrpe.cfg command definition.
command[check_crond]=/usr/local/nagios/libexec/check_procs -c 1:20 -C crond
