The basic Nagios set-up consists of a central server that polls all the Hadoop daemons - Hadoop master and slave nodes, the Templeton server, Zookeeper nodes, and HBase servers - in your installation.
Nagios checks these services for one of the following states:
OK
Warning
Critical
Nagios writes its output to a status log, /var/nagios/status.dat. The alert
information from that file is periodically collected and displayed in Ambari Web. For more
details on Nagios architecture, see the Nagios Overview at the
nagios.org web site.
Out of the box Ambari provides a set of Nagios plugins specially designed for monitoring important aspects of your Hadoop cluster.
