Hello, We have a use case that when adding or removing a new node, we hope to minimize the shuffle of partitions between nodes. I'm trying to implement a customized rebalancer calculating the new resource assignment based on the previous resource assignment. When a new node is added, just move some partitions from existing node to the new node, and when a node is down, move the partitions on this node to the other nodes. Partitions would not move between two nodes if the both status are not changed.
The documentation says: In rebalance(), ... the third is the output of the previous invocation of this method (if supported) ... During my testing I found the previous resource assignment passed in is always null. my question is what "if supported" means here? Does the rebalancer need to support something? Any other suggestions are also welcome. Thanks, Changgeng
