These release notes cover new developer and user-facing incompatibilities, important issues, features, and major improvements.
Commands chmod, chown and chgrp now returns non zero exit code and an error message on failure instead of returning zero.
The hadoop jars are renamed from previous hadoop-<version>-<name>.jar to hadoop-<name>-<version>.jar. Applications and documentation need to be updated to use the new file naming scheme.
With this incompatible change, under metrics context “dfs”, the record name “FSDirectory” is no longer available. The metrics “files_deleted” from the deleted record “FSDirectory” is now available in metrics context “dfs”, record name “namenode” with the metrics name “FilesDeleted”.