These release notes cover new developer and user-facing incompatibilities, important issues, features, and major improvements.
The TaskTracker now has a thread which monitors for a known Jetty bug in which the selector thread starts spinning and map output can no longer be served. If the bug is detected, the TaskTracker will shut itself down. This feature can be disabled by setting mapred.tasktracker.jetty.cpu.check.enabled to false.
WARNING: No release note provided for this change.
This fix is marked “incompatible” only because it changes the bin-tarball directory structure to be consistent with the source tarball directory structure. The source tarball is unchanged. RPMs and DEBs now use an intermediate bin-tarball with an “${os.arch}” tag (like the packages themselves). The un-tagged bin-tarball is now multi-platform and retains the structure of the source tarball; it is in fact generated by target “tar”, not by target “binary”. Finally, in the 64-bit RPMs and DEBs, the native libs go in the “lib64” directory instead of “lib”.
Generate integration artifacts “org.apache.hadoop:hadoop-client” and “org.apache.hadoop:hadoop-minicluster” containing all the jars needed to use Hadoop client APIs, and to run Hadoop MiniClusters, respectively. Push these artifacts to the maven repository when mvn-deploy, along with existing artifacts.