I don't particularly like having this method on the scaling strategy but I have no better solution. This is used to convert an IP to an actual instance id as part of auto scaling. When a node is created by auto scaling, it does not have an IP right away and hence we store the instance id. When a node comes up in the RTR, we only have the IP:port instead of the instance id. So this method is used by the scaling stuff to compare what is currently in the cluster to what it thinks is being provisioned and update state accordingly. The underlying scaling strategy is the only thing that has a way of doing the instance id to ip mapping.