Cloudera provides its distribution of hadoop, people are getting more attracted towards cloudera rather then original Apache hadoop. Cloudera provides almost all the sub packages which apache hadoop provides, Cloudera applys lots of patches to apache hadoop before providing it as its own distribution.
Cloudera also provides some extra subproject (which apache hadoop does not provides) like cloudera hue , Oozie, Sqoop, Flume etc
To install Cloudera:
Pseudo distributed mode: http://patodirahul.blogspot.com/2011/03/running-cloudera-in-pseudo-distributed.html