Locality scheduling broken due to mismatch between IPs and hosts

I noticed that, on a single-rack cluster, I wasn't getting hardly any data locality. The issue appears to be the code in RMContainerAllocator which changes the resource requests to use IP addresses instead of hostnames:

           //host comes from data splitLocations which are hostnames. Containers
           // use IP addresses.
           //TODO Temporary fix for locality. Use resolvers from h-common. 
           // Cache to make this more efficient ?

However, at least on my cluster, the resource manager sees node resources as hostnames, not IPs. Removing this code fixed data locality.