Group coordinator
A group coordinator is the Kafka broker responsible for managing a consumer group’s membership, liveness, partition assignments, and committed offsets.
Kafka for Architects
A group coordinator is the Kafka broker responsible for managing a consumer group and coordinating its membership and partition assignments.
- How it is used
- Coordinates consumer-group membership and partition reassignment as application instances join, leave, or fail.
- How deep it goes
- Explains coordinator discovery, assignment exchange, failure-triggered rebalances, and the next-generation heartbeat API without detailing broker internals.
- Examples
- Illustrates assignment distribution, a joining consumer triggering rebalance, and Kafka Connect worker failure redistributing tasks.
- What you can do after
- Diagnose/debug with it when consumer membership changes or failed Connect workers trigger reassignment, distinguishing those events from failed tasks.
Kafka Streams in Action, Second Edition
A group coordinator is the Kafka broker responsible for managing a consumer group's membership, rebalancing, and committed offsets.
- How it is used
- Manages consumer-group membership and initiates partition reassignment when consumers join or fail.
- How deep it goes
- Explains membership detection, timeout-driven rebalancing, partition movement, and eager versus cooperative protocols.
- Examples
- Uses new-member joins, failed consumers, heartbeat timeouts, and diagrams of eager and cooperative partition reassignment.
- What you can do after
- Diagnose why consumer-group membership changes trigger partition reassignment and processing pauses.
Read how Kafka Streams in Action, Second Edition explains group coordinator →
Apache Kafka in Action
A group coordinator is the Kafka broker responsible for managing a specific consumer group's membership, liveness, and assignments.
- How it is used
- Coordinates consumer-group membership, liveness, rejoining, and partition-distribution synchronization.
- How deep it goes
- Explains coordinator discovery, joining, heartbeats, and synchronization, but does not detail assignment algorithms.
- Examples
- Uses FindCoordinator, JoinGroup, Heartbeat, and SyncGroup requests plus a rebalance diagram.
- What you can do after
- Understand how consumers locate their coordinator and communicate during membership and rebalance operations.
Read how Apache Kafka in Action explains group coordinator →
Related concepts
- consumer group rebalancingproduces · Consumer group rebalancing is the redistribution of topic-partition assignments among consumer group members after membership or partition availability changes.
- Kafka brokerkind of · A Kafka broker is a server process in an Apache Kafka cluster that stores records and handles producer, consumer, and other client requests.
- message brokerkind of · A message broker is intermediary software that receives, routes, and delivers messages between communicating producers and consumers.
- Kafka producerused by · A Kafka producer is an application or client that publishes records to Kafka topics.
- group leaderused by · A group leader is the elected Kafka consumer-group member responsible for calculating the group’s partition assignments.
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