Hadoop Info - Be Interview Ready - YARN came before 2.x version

3. Do we know that before 2.0 , YARN, Kerberos security,HDFS federation & Namenode HA features are already  there ?

Answer :

In November 2011, version 0.23 of Hadoop was released.that has these features but that was not that matures as 2.0 version . Hence 0.23 upgraded to stable version and name as 2.0.