ZooKeeper is an open-source system which helps in managing the cluster environment of Kafka. As we know that Kafka brokers work in a cluster environment where several servers process the incoming messages before broadcasting to subscribed consumers. It is an integral part of Kafka architecture. One can not use Kafka without ZooKeeper. The client servicing becomes unavailable once ZooKeeper is down. It facilitates communication between different nodes of the cluster. In a cluster environment, only one node works as a leader while others are followers system only. It is a ZooKeeper responsibility to choose a leader in a cluster node. Whenever any server added or removed in a cluster, topic added or removed, ZooKeeper sends that information to each node. This helps in better coordination between different nodes. Choosing leadership node, better synchronization between different nodes, configuration management are the key roles of ZooKeeper.