HDFS-5776 Support 'hedged' reads in DFSClient

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1571466 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5776 Support 'hedged' reads in DFSClient

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1571467 13f79535-47bb-0310-9956-ffa450edef68
YARN-1678. Fair scheduler gabs incessantly about reservations (Sandy Ryza)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1571468 13f79535-47bb-0310-9956-ffa450edef68
YARN-1686. Fixed NodeManager to properly handle any errors during re-registration after a RESYNC and thus avoid hanging. Contributed by Rohith Sharma.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1571474 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-5761. Added a simple log message to denote when encrypted shuffle is on in the shuffle-handler. Contributed by Jian He.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1571514 13f79535-47bb-0310-9956-ffa450edef68
YARN-1734. Fixed ResourceManager to update the configurations when it transits from standby to active mode so as to assimilate any changes that happened while it was in standby mode. Contributed by Xuan Gong.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1571539 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5922. DN heartbeat thread can get stuck in tight loop. (Arpit Agarwal)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1571542 13f79535-47bb-0310-9956-ffa450edef68