Hmaster Server in HBase

Each hregion server communicates with the Hmaster server, and Hmaster's primary task is to tell each hregion server what hregion it is maintaining.

When a new Hregion server logs on to the Hmaster server, Hmaster tells it to wait for the data to be allocated first .

When a hregion crashes, Hmaster will mark its responsible hregion as unassigned , and then assign them to other hregion servers.

If the current hbase has resolved the previously existing SPFO (single point of failure), and hbase can start multiple hmaster, it can be zookeeper to ensure that there is always a master running in the system.

Distributed cluster deployment of HBase ha

Hmaster is primarily responsible for the management of table tables and hregion in its functions, including:

1, the Management user to table tables of the increase, deletion, change, check operation;

2, manage the load balance of Hregion server, adjust hregion distribution;

3, after the Hregion Division, responsible for the new hregion distribution;

4, after the Hregion server outage, responsible for the failure of the Hregion server hregion migration.

　　

Hmaster Server in HBase