MR2 and YARN Briefly Explained by Justin Kestelyn.
Justin writes:
With CDH4 onward, the Apache Hadoop component introduced two new terms for Hadoop users to wonder about: MR2 and YARN. Unfortunately, these terms are mixed up so much that many people are confused about them. Do they mean the same thing, or not?
Not but see Justin’s post for the details. (He also points to a longer post with more details.)