I haven't browsed the source for the rebalance algorithm but anecdotally It appears this is the case. In our system we have a consumer group whose application instances are not only scaled but also split by topics (some topics have much higher message rates). When we perform a deployment of one of the split instances it causes all consumers across all instances in that group to rebalance, even those not consuming that specific topic.
In my opinion I wouldn't split the consumer group deployment by topics as we have done but treat each consumer group as an "application identifier" and scale that way only. Not sure if that helps or not. -John On Tue, May 10, 2016 at 3:50 AM Spico Florin <spicoflo...@gmail.com> wrote: > I have 3 topics A,B,C with same number of partitions. I use the same group > name for all the consumers to this topics. > My questions are: > > 1. If a consumer for one of the topics/partitions will rebalance be > triggered for the other two topics consumers? > > 2. Same if adding a new partition for one topic, will rebalance be > triggered for the other two topics consumers? > > 3. More general, the consumers rebalance occurs at the group level no > matter from what topics are consuming (considering they have the same group > name)? > > I look forward for your answers. > > Regards, > Florin >