apache project zookeeper
http://hadoop.apache.org/zookeeper/ 很高兴得看到Yahoo捐献的Zookeeper已经从sourceforge迁移到Apache,并成为Hadoop的子项目.那么ZooKeeper是什么呢?Zookeeper是Google的Chubby一个开源的实现.是高有效和可靠的协同工作系统.Zookeeper能够用来leader选举,配置信息维护等.在一个分布式的环境中,我们需要一个Master实例或存储一些配置信息,确保文件写入的一致性等.Zookeeper能够保证如下3点: Watches are ordered with respect to other events, other watches, andasynchronous replies. The ZooKeeper client libraries ensures thateverything is dispatched in order. A client will see a watch event for a znode it is watching before seeing the...