So far, we have discussed the basics of the ZooKeeper service and learned in detail about the data model and its attributes. We have also been acquainted with the ZooKeeper watch concept, which is an eventing mechanism that is done when any changes are made to a znode in the ZooKeeper namespace. We read how authentication and a basic security model are implemented by exposing a set of ACLs to be associated with znodes.

In this section, we will discuss and learn about the lifetime of a client's interaction with a ZooKeeper service by introducing the concept of ZooKeeper sessions. We will also read in detail how ZooKeeper works internally by describing its protocols. It is important to know about the inner workings to gain a deep insight, which will help in designing distributed applications with ZooKeeper and understanding the intricacies of the things associated with it.

Let's start with how clients interact with a ZooKeeper service. In order for...