You can either install Apache Hadoop on your system or you can also directly use Cloudera single node Quickstart VM. Installing Apache Hadoop from scratch is a tedious process but it will give you a good experience of Hadoop configurations and tuning parameters. On the other hand, Cloudera Quickstart VM will save all the efforts and will give you a ready to use environment.
System Requirements: I would recommend you to have 8GB RAM. Allocate your VM 50+ GB of storage as you will be storing huge data sets for practice.