Kafka Error COORDINATOR_NOT_AVAILABLE
Error code 15 · Retriable Consumer
The coordinator is not available.
Common Causes
- __consumer_offsets topic does not exist yet (first consumer group on a fresh cluster with auto-creation disabled)
- All brokers that host the relevant __consumer_offsets partition are down or unreachable
- Coordinator broker is in the middle of a controlled shutdown and the new coordinator has not yet been elected
Solutions
- Verify __consumer_offsets topic exists: kafka-topics.sh --list --bootstrap-server localhost:9092 | grep __consumer_offsets; if missing, ensure 'auto.create.topics.enable=true' or create it manually
- Check which broker is the coordinator for the group: kafka-consumer-groups.sh --bootstrap-server localhost:9092 --group <group> --describe; verify that broker is running
- Ensure 'offsets.topic.replication.factor' is <= the number of available brokers; a cluster with fewer brokers than this setting will fail to elect a coordinator
Diagnostic Commands
# Inspect __consumer_offsets topic health
kafka-topics.sh --describe --topic __consumer_offsets --bootstrap-server localhost:9092
# Check which broker is the group coordinator
kafka-consumer-groups.sh --bootstrap-server localhost:9092 --group <group> --describe 2>&1 | grep -E 'Coordinator|ERROR'Related APIs
This error can be returned by: AddOffsetsToTxn · AddPartitionsToTxn · AlterShareGroupOffsets · ConsumerGroupDescribe · ConsumerGroupHeartbeat · DeleteGroups · DeleteShareGroupOffsets · DeleteShareGroupState · DescribeGroups · DescribeShareGroupOffsets · EndTxn · FindCoordinator · Heartbeat · InitProducerId · InitializeShareGroupState · JoinGroup · LeaveGroup · ListGroups · ListTransactions · OffsetCommit · OffsetDelete · OffsetFetch · ReadShareGroupState · ReadShareGroupStateSummary · ShareGroupHeartbeat · StreamsGroupDescribe · StreamsGroupHeartbeat · SyncGroup · TxnOffsetCommit · WriteShareGroupState · WriteTxnMarkers
Debugging Kafka errors? Conduktor Console gives you real-time visibility into your cluster. Explore all errors in the Error Decoder.