Apache Zookeeper is a very useful service for Coordination between various high-performance services. For example, It is used by HDFS, Kafka, Hive, HBase for coordination.
It is a very hands-on chapter on Zookeeper along with concepts of distributed computing such as the Paxos algorithm. I am sure you will be able to appreciate the utility of Zookeeper by the end of this session.
Happy Hands-On Learning!