# org.apache.kafka.common.errors.GroupMaxSizeReachedException: The consumer group has reached its maximum size

- **ID:** `kafka/group-max-size-exceeded`
- **Domain:** kafka
- **Category:** resource_error
- **Verification:** ai_generated
- **Fix Rate:** 88%

## Root Cause

The consumer group has exceeded the maximum number of members configured by group.max.size.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 3.5.0 | active | — | — |
| 3.6.0 | active | — | — |
| 3.7.0 | active | — | — |

## Workarounds

1. **Increase group.max.size on the broker via kafka-configs.sh:
kafka-configs.sh --bootstrap-server localhost:9092 --entity-type brokers --entity-default --alter --add-config group.max.size=20** (95% success)
   ```
   Increase group.max.size on the broker via kafka-configs.sh:
kafka-configs.sh --bootstrap-server localhost:9092 --entity-type brokers --entity-default --alter --add-config group.max.size=20
   ```
2. **Reduce the number of consumer instances in the group by consolidating partitions to fewer consumers.** (85% success)
   ```
   Reduce the number of consumer instances in the group by consolidating partitions to fewer consumers.
   ```

## Dead Ends

- **** — Restarting consumers individually does not resolve the underlying configuration limit. (95% fail)
- **** — Deleting offsets only resets consumption progress, not the group membership count. (90% fail)