check Hadoop datanodes

Perl script to check the number of Hadoop datanodes alive

useage:

Nagios Configuration
services.cfg

define service {
use generic-service
host_name [namenode's host]
service_description check_remote_datanode
contact_groups admins
check_command check_remote_datanode!15!13
}

above example says that:
check_remote_datanode returns
1 ("WARNING") if the number of datanodes alive is equal or less than 15
2 ("CRITICAL") if the number of datanodes alive is equal or less than 13
0 ("OK") if the number of datanodes alive is more than 15

commands.cfg
define command {
command_name check_remote_datanode
command_line /usr/local/bin/check_hadoop_datanode.pl $HOSTADDRESS$ $ARG1$ $ARG2$
}