The Hadoop 2 release

YARN came into the picture with the release of Hadoop 0.23 on November 11, 2011. This was the alpha version of the Hadoop 0.23 major release.

The major difference between 0.23 and pre-0.23 releases is that the 0.23 release had undergone a complete revamp in terms of the MapReduce engine and resource management. This 0.23 release separated out resource management and application life cycle management.