To quote Guozhang Wang :
"The proposal is that, we extend FindCoordinatorRequest to have multiple consumer ids: today each FindCoordinatorRequest only contains a single consumer id, so in our scenario we need to send N request for N consumer groups still. If we can request for coordinators in a single request, then the workflow could be simplified to:
- send a single FindCoordinatorRequest to a broker asking for coordinators of all consumer groups.
1.a) note that the response may still succeed in finding some coordinators while error on others, and we need to handle them on that granularity (see below).
- and then for the collected coordinator, group them by coordinator id and send one request per coordinator destination.
Note that this change would require the version to be bumped up, to FIND_COORDINATOR_REQUEST_V3 for such protocol changes, also the RESPONSE version should be bumped up in order to include multiple coordinators."
A KIP is needed.