Hi, I recently moved some KafkaStreams applications from v0.10.2.1 to v1.1.1 and now I notice a weird behaviour in the partition assignment. When starting 4 instances of my Kafka Streams application (on v1.1.1) I see that 17 of the 20 partitions (of a source topic) are assigned to 1 instance of the application while the other 3 instances only get 1 partition assigned. (previously (on v0.10.2.1) the all got 5 partitions.)
Is this expected behaviour, as I read that quite some improvements were done in the partition assignment strategy for Kafka Streams applications? If yes, how can I make it so that the partitions are equally devided again across all running applications? It's a bit weird in my opinion as this makes scaling the application very hard. Also, when initially starting with 1 instance of the application, and gradually scaling up, the new instances only get 1 partition assigned ... All my Streams applications use default configuration (more or less), running 1 stream-thread. Any suggestions / enlightenments on this? Greets, Bart
