How Scaling Really Works in Apache HBase by Matteo Bertozzi.
From the post:
At first glance, the Apache HBase architecture appears to follow a master/slave model where the master receives all the requests but the real work is done by the slaves. This is not actually the case, and in this article I will describe what tasks are in fact handled by the master and the slaves.
You can use a tool or master a tool.
Recommend the latter.