Assume rollout scenario - after new application is started, old one is stopped. Each application has 4 members.
When 1st member from new application starts and request “sendJoinGroupRequest”, Kafka disconnects old members and waits for them to rejoin for rebalance timeout.
Old members may rejoin quickly, before 2nd member from new application request join-group. It may happen that each new member will trigger new rebalance.
Is it possible to configure Kafka to give some time for new joiners, similar to rebalance timeout for re-joiners?
I understand that when member leaves a group, Kafka should find a replacement as soon as possible, because topic data is waiting.
But when members exists, topic data is processed and new member come, I do not see any objection to wait short time for more new members.