Apache Hadoop 2.0.0-alpha Release Notes

These release notes cover new developer and user-facing incompatibilities, important issues, features, and major improvements.


WARNING: No release note provided for this incompatible change.


The daemon stop action no longer returns failure when stopping an already stopped service.


This change will affect the output of errors for some Hadoop CLI commands. Specifically, the name of the exception class will no longer appear, and instead only the text of the exception message will appear.


WARNING: No release note provided for this incompatible change.


Hadoop log files are now rolled by size instead of date (daily) by default. Tools that depend on the log file name format will need to be updated. Users who would like to maintain the previous settings of hadoop.root.logger and hadoop.security.logger can use their current log4j.properties files and update the HADOOP_ROOT_LOGGER and HADOOP_SECURITY_LOGGER environment variables to use DRFA and DRFAS respectively.


Reduce number of object created by JMXJsonServlet. (Devaraj K via Eric Yang)


WARNING: No release note provided for this incompatible change.


WARNING: No release note provided for this incompatible change.


This change modifies DatanodeID, which is part of the client to server protocol, therefore clients must be upgraded with servers.


This change modifies DatanodeID, which is part of the client to server protocol, therefore clients must be upgraded with servers.


This change modifies DatanodeID, which is part of the client to server protocol, therefore clients must be upgraded with servers.


Upgrade from Hadoop versions earlier than 0.18 is not supported as of 2.0. To upgrade from an earlier release, first upgrade to 0.18, and then upgrade again from there.


The ‘namenode -format’ command now supports the flags ‘-nonInteractive’ and ‘-force’ to improve usefulness without user input.


The fsck “move” option is no longer destructive. It copies the accessible blocks of corrupt files to lost and found as before, but no longer deletes the corrupt files after copying the blocks. The original, destructive behavior can be enabled by specifying both the “move” and “delete” options.


This is a new feature. It is documented in hdfs_user_guide.xml.


The HA NameNode may now be started with the “-bootstrapStandby” flag. This causes it to copy the namespace information and most recent checkpoint from its HA pair, and save it to local storage, allowing an HA setup to be bootstrapped without use of rsync or external tools.


To run secure Datanodes users must install jsvc for their platform and set JSVC_HOME to point to the location of jsvc in their environment.


WARNING: No release note provided for this incompatible change.


Fixed broken compilation in TestSubmitJob after the patch for HDFS-2895.