What is the role of ZooKeeper in HBase?

ZooKeeper plays a crucial role in HBase, mainly in the following aspects:

1. Coordination Service: ZooKeeper is used to manage the state information of each node in the HBase cluster, coordinating communication and collaboration between nodes to ensure consistency and reliability within the cluster.
2. Metadata Management: Metadata information of HBase, such as table structure and region distribution, is stored in ZooKeeper. HBase uses ZooKeeper to access and maintain this metadata information.
3. Election mechanism: The Master node in the HBase cluster is elected by ZooKeeper, which is responsible for monitoring the status of the Master node and conducting a re-election when the Master node fails.
4. ZooKeeper offers a mechanism for managing distributed locks, which HBase can utilize to ensure data consistency and concurrency.

In conclusion, ZooKeeper plays a role in HBase similar to that of a coordinator and metadata manager, providing the necessary support for the stable operation and high availability of the HBase cluster.