• 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.

kafka consumers

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

kafka consumers_group

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