Metrics usage in JMX, ganglia or nagios

Discovering Available Metrics

Rather than listing each metric which HBase emits by default, you can browse through the available metrics, either as a JSON output or via JMX. Different metrics are exposed for the Master process and each region server process.

Procedure: Access a JSON Output of Available Metrics

• After starting HBase, access the region server’s web UI, at http://REGIONSERVER_HOSTNAME:60030 by default (or port 16030 in HBase 1.0+).
• Click the Metrics Dump link near the top. The metrics for the region server are presented as a dump of the JMX bean in JSON format. This will dump out all metrics names and their values. To include metrics descriptions in the listing — this can be useful when you are exploring what is available — add a query string of ?description=true so your URL becomes http://REGIONSERVER_HOSTNAME:60030/jmx?description=true. Not all beans and attributes have descriptions.
• To view metrics for the Master, connect to the Master’s web UI instead (defaults to http://localhost:60010 or port 16010 in HBase 1.0+) and click its Metrics Dump link. To include metrics descriptions in the listing — this can be useful when you are exploring what is available — add a query string of ?description=true so your URL becomes http://REGIONSERVER_HOSTNAME:60010/jmx?description=true. Not all beans and attributes have descriptions.

You can use many different tools to view JMX content by browsing MBeans. This procedure uses jvisualvm, which is an application usually available in the JDK.

Procedure: Browse the JMX Output of Available Metrics

• Start HBase, if it is not already running.
• Run the command jvisualvm command on a host with a GUI display. You can launch it from the command line or another method appropriate for your operating system.
• Be sure the VisualVM-MBeans plugin is installed. Browse to Tools → Click Installed and check whether the plugin is listed. If not, click Available Plugins, select it, and click Install. When finished, click Close.
• To view details for a given HBase process, double-click the process in the Local sub-tree in the left-hand panel. A detailed view opens in the right-hand panel. Click the MBeans tab which appears as a tab in the top of the right-hand panel.
• To access the HBase metrics, navigate to the appropriate sub-bean: .* Master: .* RegionServer:
• The name of each metric and its current value is displayed in the Attributes tab. For a view which includes more details, including the description of each attribute, click the Metadata tab.