In this chapter, we learned the basics of a ZooKeeper service followed by the ZooKeeper data model. We read about the different operations supported by the data model and the eventing mechanism associated with it. We also studied in detail about the intricate details of how ZooKeeper is implemented from the protocol, how it maintains consistency guarantees, transaction-processing through a two-phase atomic broadcast scheme, and so on.

In the next chapter, we will dive into the programming of Apache ZooKeeper. We will learn about the ZooKeeper API model by getting acquainted with the client libraries. In addition to this, we will look at programs to use the APIs, which will be a big stepping stone to writing distributed applications using ZooKeeper.