We introduced in the section Topics, partitions, and offsets the notion of brokers. Brokers are deployed on multiple machines, and all the brokers form what we call a Kafka cluster.

If you want to connect to a Kafka cluster, all you need to know is the address of one of the brokers. All the brokers know about all the metadata of the cluster—brokers, partitions, and topics. Internally, Kafka uses a product named Zookeeper. This allows the sharing of all this metadata between brokers.