Using the open source monitoring system Nagios, Ambari gathers information on the status of both of the hosts and the services that run on them.
Host and System Information: Ambari monitors basic host and system information such as CPU utilization, disk I/O bandwidth and operations per second, average memory and swap space utilization, and average network latency.
Service Information: Ambari monitors the health and performance status of each service by presenting information generated by that service. Because services that run in master/slave configurations (HDFS, MapReduce, and HBase) are fault tolerant in regard to service slaves, master information is presented individually, whereas slave information is presented largely in aggregate.
Alert Information: Using Nagios with Hadoop-specific plug-ins and configurations, Ambari Web can issue alerts based on service states defined on three basic levels:
OK
Warning
Critical
The thresholds for these alerts can be tuned using configuration files, and new alerts can be added. For more details on Nagios architecture, see the Nagios Overview at the
nagios.orgweb site.
