Explain use of alternatives when multiple configs are used

At some point, one may be puzzled with multiple config files in /etc/hadoop/conf, /etc/hadoop/pseudo.mr1/ and so on.

It would be helpful for newcomers to explain the use of alternatives in the CDH4 installation documentation. Since the most difficult part of CDH is configuration, modifying config files without being sure you are modifying the good one is non optimal.

Quoting Harsh J. in the mailing list :
"you can run "sudo alternatives --display
hadoop-conf" and see which is current. Your output should point to
mapreduce1 being the currently used alternative, which would be
correct in case of CM deployed client configs.
"