Since the word Hadoop is so frequently used to refer to the entire suite of open source tools around the core capability, one thing to keep in mind is that you will also need to download several other packages. You don’t really want to do that individually do you? If you download every package separately then you are responsible for making sure it is all integrated, and you will be responsible for making sure that changes to the underlying components are maintained and updated.
That means the best way to start with Hadoop is to download a distribution. Start with the always free to use CDH from Cloudera. CDH stands for Cloudera Distribution including Apache Hadoop. CDH includes components that have been tested together and are known to work. So starting your activity with CDH is the smart way to go.
To download CDH see: https://ccp.cloudera.com/display/SUPPORT/Downloads
You can also download the free version of a a configuration manager called the Service and Configuration Manager (SCM) Express Edition which will get you up and running fast.
More from the download page:
Find out why Cloudera’s Distribution Including Apache Hadoop (CDH) is downloaded more than all the other distributions combined.
Service and Configuration Manager (SCM) Express Edition
Simple, Installer-Based CDH Deployment
SCM Express 3.6.1
Last update: 07/22/2011
Cloudera’s SCM Express Edition will build and configure your single or multi-node CDH cluster and help you manage future changes to it. This software is free to use for up to 50 nodes with no term limit. To try SCM Express Edition, click the ‘Download SCM Express’ link below.
See all at: https://ccp.cloudera.com/display/SUPPORT/Downloads