In the FifoScheduler, the assignNodeLocalContainers method is checking if the data is local to a node by searching for the nodeAddress of the node in the set of outstanding requests for the app. This seems to be incorrect as it should be checking hostname instead. The offending line of code is 455:
Requests are formated by hostname (e.g. host1.foo.com) whereas node addresses are a concatenation of hostname and command port (e.g. host1.foo.com:1234)
In the CapacityScheduler, it's done using hostname. See LeafQueue.assignNodeLocalContainers, line 1129
Note that this bug does not affect the actual scheduling decisions made by the FifoScheduler because even though it incorrect determines that a request is not local to the node, it will still schedule the request immediately because it's rack-local. However, this bug may be adversely affecting the reporting of job status by underreporting the number of tasks that were node local.