Hi Kafka Community! I would like to start a discussion for KIP-1268. This KIP proposes enforcing a guardrail in the Controller API to reject such requests by default to ensure cluster stability, while providing an opt-in configuration for emergencies.
Internal topics (__transaction_state, __consumer_offsets, __share_group_state) rely on hashing logic strictly dependent on the partition count. Although the documentation explicitly advises against modifying these topics, there is currently no hard guardrail preventing it. Expanding these topics causes split-brain scenarios. This is not limited to transactions; expanding __consumer_offsets shifts Group ID mappings, leading to non-deterministic offset operation failures and potentially making groups unfindable. Similar risks apply to __share_group_state. KIP: https://cwiki.apache.org/confluence/display/KAFKA/KIP-1268%3A+Prevent+Dynamic+Partition+Expansion+of+Internal+Topics Best regards, Sanghyeok An
