2.1. Patch information for Hadoop

Hadoop is patched to include the following:

HDFS-3652: Fixed edit stream issues caused in the event of FSEditlog failure.
MAPREDUCE-4399: Fixed performance regression in shuffle.
HADOOP-7154: Added support to set MALLOC_ARENA_MAX in hadoop-config.sh file.
HADOOP-5464: Added support for disabling write timeout. To do this, you can set zero values for dfs.socket.timeout and dfs.datanode.socket.write.timeout parameters.
HDFS-2617: Replaced Kerberized SSL for image transfer and fsck with SPNEGO-based solution.
HDFS-3466: Fixed SPNEGO filter to use the DFS_WEB_AUTHENTICATION_KERBEROS_KEYTAB_KEY to find the keytab.
HDFS-3461: Fixed HFTP to use the same port and protocol while ontaining the delegation token.
HADOOP-6947: Fixed Kerberos relogin to configure the refreshKrb5Config correctly.
MAPREDUCE-3837: Enhanced JobTracker job recivery mechanism in the event of a crash.