Apache Hadoop is the Hadoop distribution from Apacge group while Cloudera Hadoop has its own supply of Hadoop which is designed on top of Apache Hadoop, so it does not have latest release of Hadoop.
Cloudera contains extra tools while Hadoop distribution like Cloudera Search, Impala, cloudera Navigator and Cloudera Manager are not involved in Cloudera Hadoop.
Apache Hadoop open source product so no support available . Cloudera , hartonworks mapr EMR, these are Hadoop distributions means they took open source product modified added extra flavor and sold. So those companies give support as well . So internally cloudera using Apache Hadoop only …
Cloudera is an umbrella product which deal with big data systems. Having Apache Hadoop at core, Cloudera has created an architecture which has almost all components necessary to process bigdata.