title: what are the differences zookeeper, journal node tasks and quorum journal manager in hadoop?
body: <p>On studying the material in multiple no of websites and videos, I am confused with the functionalities and differences in the purposes of the 3 hadoop components ZooKeeper, Journal Node and the Quorum Journal Manager.</p>
  
  <p>Could anyone please explain me the reasons for inventing each of the above and differences in the purposes and functionalities of the above three components?</p>
  
  <p>Thanks in advance.</p>