Youssef Ismail created KAFKA-21022:
--------------------------------------
Summary: Broker Crash During ZK-to-KRaft Migration Due to Missing
Topic ID in Empty Log Directory
Key: KAFKA-21022
URL: https://issues.apache.org/jira/browse/KAFKA-21022
Project: Kafka
Issue Type: Bug
Components: kraft, migration
Affects Versions: 3.9.1
Reporter: Youssef Ismail
While migrating a cluster from ZooKeeper to KRaft, during migration mode
brokers can crash after receiving a full {{LeaderAndIsr}} request from the
KRaft controller with the following error:
{code:java}
java.lang.RuntimeException: The log dir ... does not have a topic ID,{code}
During migration, Kafka checks the broker’s existing log directories through
{{{}findStrayReplicas{}}}. Unlike the normal KRaft startup path, this method
throws an exception when a topic ID is missing which is not allowed when
running in KRaft mode:
* [Migration path in
ReplicaManager|https://github.com/apache/kafka/blob/3.9/core/src/main/scala/kafka/server/ReplicaManager.scala#L1932-L1941]
* [Exception in
findStrayReplicas|https://github.com/apache/kafka/blob/3.9/core/src/main/scala/kafka/log/LogManager.scala#L1667-L1671]
OSS addressed a similar problem in KAFKA-16814 and [PR
#16165|https://github.com/apache/kafka/pull/16165]. That fix treats a log
without a topic ID as stray during normal KRaft startup but the
migration-specific {{findStrayReplicas}} path still throws.
I recovered by stopping the affected broker, removing the empty log directory,
and restarting it in migration mode.
I propose updating {{findStrayReplicas}} to handle a missing topic ID the same
way as the normal KRaft path: treat the empty log as stray instead of crashing
the broker.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
