Zookeeper is a service used to track the health of the nodes.
Zookeeper keep a quorum (logic topic on machine).
ZooKeeper is a coordination service for distributed applications.
It provides a shared hierarchical namespace that is organized like a standard file system.
The namespace consists of data registers called znodes, for ZooKeeper data nodes, which are similar to files and directories.
A name in the namespace is a sequence of path elements where each element is separated by a / character, such as the path /app1/p_2
- Hortonworks: zookeeper-client