Each node must have an NRPE plugin installed with the checks described earlier in /usr/local/nagios/libexec and the commands specified in /usr/local/nagios/etc/nrpe.cfg, shown as follows:

command[check_jt_heap]=/usr/local/nagios/libexec/check_hadoop_namenode.pl -H $HOSTADDRESS$ -u $USER8$ -P $PORT$ -b $ARG2$
command[check_tasktracker]=/usr/local/nagios/libexec/check_tasktracker 

Similarly, entries need to be made for each of the checks to be executed on the nodes.