svn merge -r 1451340:1451341 Merging from trunk to branch-2 to fix YARN-269.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1451342 13f79535-47bb-0310-9956-ffa450edef68
svn merge -r 1451375:1451376 Merging from trunk to branch-2 to fix HADOOP-9336.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1451381 13f79535-47bb-0310-9956-ffa450edef68
HDFS-4518. Merge 1451348 from trunk.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1451387 13f79535-47bb-0310-9956-ffa450edef68
merge YARN-406 from trunk. Fix TestRackResolver to function in networks where "host1" resolves to a valid host. Contributed by Hitesh Shah.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1451392 13f79535-47bb-0310-9956-ffa450edef68