Kafka Error BROKER_ID_NOT_REGISTERED
Error code 102 · Non-retriable Broker
The given broker ID was not registered.
Common Causes
- An admin or internal request referenced a broker ID that has been decommissioned or has not yet completed its KRaft registration
- Broker is in the process of starting up and has not yet sent its BrokerRegistration request to the controller
- Partition reassignment was attempted targeting a broker ID that no longer exists in the cluster
Solutions
- Verify the broker is alive and registered: run kafka-broker-api-versions.sh against that broker's host and check kafka-metadata-quorum.sh --bootstrap-server localhost:9092 describe --status for its registration status
- If decommissioning, ensure all partition replicas are migrated off the broker before removing it from the cluster
- Retry the operation after the broker completes startup — check server.log for 'Registered broker' message confirming successful registration
Diagnostic Commands
# Check broker supported API versions
kafka-broker-api-versions.sh --bootstrap-server <broker-host>:9092
# Look for broker registration events
grep 'BrokerIdNotRegistered\|Registered broker\|broker registration' /var/log/kafka/server.log | tail -20Related APIs
This error can be returned by: BrokerHeartbeat · UnregisterBroker
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