slaves registers on JobTracker as "localhost"
And JobTracker trying to fetch data from "localhost" when he "wants" to
fetch data from slaves.
But word "localhost" not contains neither in /etc/hosts, not in any other
linux network or hadoop config file.
For example, my slave's /etc/hosts:
and JobTracker trying to connect to it by "localhost".
(but many times mentions in hadoop's java-sources)