Our popular Hadoop for Java Developers course was recorded using version 2.4.0 of Hadoop. Since the course was released there have been some further releases of Hadoop, with the current version being 2.6.0.
There are no differences in the content that we cover on the course between the two versions of Hadoop, so the course is completely valid if you wish to use 2.6.0 or 2.4.0. In this blog post, however, I want to point out a reason to stick with version 2.4.0, and a couple of pointers that you should be aware of if you are going to use 2.6.0. I'll also mention the process to upgrade from 2.4.0 to 2.6.0.
Which Version of Hadoop should I use?
If you're starting to develop with Hadoop today then you might just want to download the latest version from the Hadoop website (2.6.0) and there is only really one reason that I can think of not to do this... and that is that Amazon's Elastic Map Reduce (EMR) service, which can be used to run Hadoop jobs "in the cloud" is not yet compliant with versions of Hadoop newer than 2.4.0.