One of the most important parts of HBase operation tasks is to monitor the cluster and make sure it is running as expected. HBase inherits its monitoring APIs from Hadoop. It exposes a lot of metrics, which gives the insight information of the cluster's current status, including region-based statistics, RPC details, and the Java Virtual Machine (JVM) memory and garbage collection data.
These metrics are then subsequently configured to expose to JMX and Ganglia, which makes the metrics visible through graphs. Ganglia is the recommended tool for monitoring large-scale clusters. Ganglia itself is a scalable, distributed system; it is said to be able to handle clusters with 2000 nodes.
We will describe how to use Ganglia to monitor an HBase cluster in this recipe. We will install Ganglia Monitoring Daemon (Gmond) on each node in the cluster, which will gather the server and HBase metrics of that node. These metrics are then subsequently polled...