Hi everyone, I would like to start a discussion for this small KIP.
https://cwiki.apache.org/confluence/x/UZc8G Rebalance is the most important consumer event, and Kafka is moving toward server-side rebalance. Today, client-side/sdk callbacks are useful but not always reliable operationally (SDK dependency, Not easy for central management). In incidents, key rebalance evidence is often missing on the client side.On the broker side, logs and metrics are still limited for automation: logs are hard to integrate reliably, and metrics do not include the most actionable key (group.id). This KIP proposes a lightweight broker-side callback to expose key rebalance context (including group.id) for centralized observability and automation, without forcing client upgrades and without adding high-cardinality metric tags. Your feedback is greatly appreciated. Thank you! Regards Jian
