What is the ZooKeeper address format used in these Kafka command examples?

• A. localhost:2181
• B. localhost:9092
• C. 127.0.0.1:2181
• D. zookeeper:2181

Answer: (A)

ZooKeeper is addressed with a host and a port in the form host:port, and 2181 is the default port for ZooKeeper. In these Kafka command examples the ZooKeeper service is on the local machine, so the address shown is localhost:2181. The port 9092 belongs to Kafka brokers, not ZooKeeper, so that would point to a broker instead of the ZooKeeper service. Using 127.0.0.1:2181 would connect to the same local host, so it’s functionally equivalent, but the exact string in the examples uses localhost. A hostname like zookeeper:2181 could work if that host resolves in the environment, but it isn’t the exact format used in the given examples.