YARN-2874. Dead lock in DelegationTokenRenewer which blocks RM to execute any further apps. (Naganarasimha G R via kasha)
YARN-2891. Failed Container Executor does not provide a clear error message. Contributed by Dustin Cote. (harsh)
YARN-2880. Added a test to make sure node labels will be recovered if RM restart is enabled. Contributed by Rohith Sharmaks
HADOOP-11332. KerberosAuthenticator#doSpnegoSequence should check if kerberos TGT is available in the subject. Contributed by Dian Fu.