Installation

Start by deciding which user you’d like to run Hadoop as. For trying out Hadoop or developing Hadoop programs, it is simplest to run Hadoop on a single machine using your own user account.

Download a stable release, which is packaged as a gzipped tar file, from the Apache Hadoop releases page, and unpack it somewhere on your filesystem:

% tar xzf hadoop-x.y.z.tar.gz

Before you can run Hadoop, you need to tell it where Java is located on your system. If you have the JAVA_HOME environment variable set to point to a suitable Java installation, that will be used, and you don’t have to configure anything further. (It is often set in a shell startup file, such as ~/.bash_profile or ~/.bashrc.) Otherwise, you can set the Java installation that Hadoop uses by editing conf/hadoop-env.sh and specifying the JAVA_HOME variable. For example, on my Mac, I changed the line to read: