KIP-860 — Add client-provided option to guard against replication factor change during partition reassignments

Accepted Kafka 4.1 AdminBroker

Adds a validateOnly option to the AlterPartitionReassignments AdminClient API that lets callers verify a reassignment request (including replication factor impact) without executing it, and adds a targetReplicationFactor field to prevent accidental RF changes. AdminClient#describeTopics returns the full intermediate replica set during ongoing reassignments, making it impossible for callers to reliably compute the current RF without a TOCTOU race condition.

Protocol Impact

Metadata · UpdateMetadata · AlterPartitionReassignments

Details