CDH or Cloudera's Distribution Including Apache Hadoop is an enterprise-level distribution including Apache Hadoop and several components of its ecosystem such as Apache Hive, Apache Avro, HBase, and many more. CDH is 100 percent open source. It is the most downloaded distribution in its space. As of writing this book, the current version of CDH is CDH 5.0.
Some of the important features of CDH are as follows:
All components are thoroughly tested by Cloudera, to see that they work well with each other, making it a very stable distribution
All enterprise needs such as security and high availability are built-in as part of the distribution
The distribution is very well documented making it easy for anyone interested to get the services up and running quickly