Kafka Consumers

Consumers

• Consumers read data from a topic (identified by name)
• Consumers know which broker to read from
• In case of broker failures, consumes know how to recover
• Data is read in order within each partitions.

Consumer Groups

• Consumers read data in consumer groups
• Each consumer within a group reads from exclusive partitions
• If you have more consumers than partitions, some consumers will be inactive

Note: Consumers will automatically use a GroupCoordinator and a ConsumerCoordinator to assign a consumer to a partition.

What if too many Consumers?

• If you have more consumers than partitions, some consumers will be inactive