KIP-469 — Pre-registration support for static members

Discussion Consumer

Adds pre-registration support for static group members, allowing operators to pre-populate group.instance.id assignments before new instances start, so the group can be pre-sized without triggering rebalances as instances come online. Scaling up a static-membership consumer group still caused repeated rebalances as each new member joined sequentially, since membership slots weren't reserved in advance.

Protocol Impact

JoinGroup · LeaveGroup

Details