HBase and ZooKeeper roles in Hadoop?

hadoop

Solution

First of all I would strongly recommend you to go through the official pages of these projects. Go here for HBase and here for Zookeeper.

HBase is a NoSQL datastore that runs on top of your existing Hadoop cluster(HDFS). It provides you capabilities like random, real-time reads/writes, which HDFS being a FS lacks. Since it is a NoSQL datastore it doesn't follow SQL conventions and terminologies. HBase provides a good set of APIs( includes JAVA and Thrift). Along with this HBase also provides seamless integration with MapReduce framework. But, along with all these advantages of HBase you should keep this in mind that random read-write is quick but always has additional overhead. So think well before ye make any decision.

ZooKeeper is a high-performance coordination service for distributed applications(like HBase). It exposes common services like naming, configuration management, synchronization, and group services, in a simple interface so you don't have to write them from scratch. You can use it off-the-shelf to implement consensus, group management, leader election, and presence protocols. And you can build on it for your own, specific needs.

HBase relies completely on Zookeeper. HBase provides you the option to use its built-in Zookeeper which will get started whenever you start HBAse. But it is not good if you are working on a production cluster. In such scenarios it's always good to have a dedicated Zookeeper cluster and integrate it with your HBase cluster.

Note : You should always have odd number of nodes in your ZK Quorum.

HTH

Problem

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