Gaurav Garg has an article on installing Apache Kafka on a fresh Ubuntu installation:
For beginners, the default configurations of the Kafka broker are good enough, but for production-level setup, one must understand each configuration. I am going to explain some of these configurations.
broker.id: The ID of the broker instance in a cluster.zookeeper.connect: The ZooKeeper address (can list multiple addresses comma-separated for the ZooKeeper cluster). Example:localhost:2181,localhost:2182.zookeeper.connection.timeout.ms: Time to wait before going down if, for some reason, the broker is not able to connect.
Read the whole thing.