Is it possible to have a consumer rebalancing partition assignment strategy that will rebalance with a minimal number of reassignments?
Per the "Kafka 0.9 Consumer Rewrite Design" it should be possible to define my own partition assignment strategy: "partition.assignment.strategies - may take a comma separated list of properties that map the strategy's friendly name to to the class that implements the strategy. This is used for any strategy implemented by the user and released to the Kafka cluster. By default, Kafka will include a set of strategies that can be used by the consumer." Is there a Jira ticket that tracks adding user defined partitions.assignment.strategies? In the latest source, range, and roundrobin are still the only possible values (hard-coded). I assume that any user implemented strategy would have to implement the PartitionAssignor trait. If so, by naively looking at the 0.8.3 source, a strategy that should do a minimal number of partition reassignments would need the ConsumerMetaData. That's not currently available in the PartitionAssignor contract - assign(topicsPerConsumer, partitionsPerTopic). Have there been any discussion to change the contract to pass ConsumerMetaData?
