Kafka InvalidGroupIdException: Fixing the group.id Error
Hitting InvalidGroupIdException: "you must provide a valid group.id"? Why subscribe() and offset commits require a group.id in Kafka, and the exact fix.
kafka-consumer
9 PostsKafka InstanceAlreadyExistsException: AppInfo Mbean Fix
Kafka logs 'Error registering AppInfo mbean javax.management.InstanceAlreadyExistsException'. Here's what a duplicate client.id really breaks and how to fix it.
Kafka InconsistentGroupProtocolException: Cause and Fix
Kafka InconsistentGroupProtocolException: the group member's supported protocols are incompatible. Why it hits mid-upgrade and how to fix the assignor mismatch.
Kafka FETCH_SESSION_ID_NOT_FOUND: Causes and Fix
Kafka logs spamming FETCH_SESSION_ID_NOT_FOUND or INVALID_FETCH_SESSION_EPOCH? Here's what the fetch session cache is doing and how to stop the noise.
Kafka FencedInstanceIdException: Fix Static Membership Collisions
FencedInstanceIdException means two live consumers share one group.instance.id. Here's why the broker fences the old one, and how to fix it for good.
Kafka "Failed to construct kafka consumer": Every Cause, Fixed
KafkaException: Failed to construct kafka consumer — how to triage every common cause (deserializer class, classpath, DNS, JAAS, SSL) and fix each one fast.
Kafka CorruptRecordException: Record Is Corrupt — Fix It
Kafka CorruptRecordException: Record is corrupt (stored crc != computed crc). Why the CRC check fails, how to recover the partition, and how to stop it recurring.
Kafka: Consumer Is Not Subscribed to Any Topics — Fix
IllegalStateException: Consumer is not subscribed to any topics or assigned any partitions — why poll() throws it, the subscribe/assign contract, and the fix.
Fix KafkaConsumer Is Not Safe for Multi-Threaded Access
Hitting ConcurrentModificationException: KafkaConsumer is not safe for multi-threaded access? Here's why the thread guard fires and the correct fix.