ZooKeeper - A Reliable, Scalable Distributed Coordination System

ZooKeeper - A Reliable, Scalable Distributed Coordination System

Abstract
ZooKeeper is a high available and reliable coordination system. Distributed applications use ZooKeeper to store and mediate updates key configuration information. ZooKeeper can be used for leader election, group membership, and configuration maintenance. In addition ZooKeeper can be used for event notification, locking, and as a priority queue mechanism. It's a sort of central nervous system for distributed systems where the role of the brain is played by the coordination service, axons are the network, processes are the monitored and controlled body parts, and events are the hormones and neurotransmitters used for messaging. Every complex distributed application needs a coordination and orchestration system of some sort, so the ZooKeeper folks at Yahoo decide to build a good one and open source it for everyone to use.

P.S. So ZooKeeper is open-source realization (from Yahoo) of "close-source" Chubby lock service (from Google).