KIP-409 — Allow creating under-replicated topics and partitions

Discussion Broker

Allows `CreateTopics` and `CreatePartitions` requests to succeed even when fewer brokers are available than the requested replication factor, creating partitions in an under-replicated state initially. Currently, any broker outage—even a routine rolling restart—blocks all topic and partition creation because the broker enforces that all replica slots be assigned to live brokers before acknowledging the request.

Protocol Impact

CreateTopics · CreatePartitions

Details