Hadoop-KFS-FileSystem API

[Wasim Bari]

Hi,
    I am looking to use KFS as storage with Hadoop FileSystem API.

http://hadoop.apache.org/core/docs/current/api/org/apache/hadoop/fs/kfs/package-summary.html

This page states about KFS usage with Hadoop and stated as last step to run 
map/reduce tracker.

Is it necessary to turn it on? 

How only storage works with FileSystem API ?

Thanks

Wasim