Download Hadoop from the Cloudera website. You would need the tar file. I downloaded the Hadoop 0.20.2 version.
Untar and set up an environment variable HADOOP_HOME to point to that location.
cd to the conf folder
update the hdfs-site.xml file with these changes (replace the items in bold to relevant folders and they need to have the right permissions): <property>
Update the core-site.xml with: <property>
Update the “masters” and “slaves” configuration files with “localhost”
Make sure that ssh is turned on for your Mac.
Format the DFS: hadoop namenode -format
Run start-all.sh => this should start the following processes: $ jps
Copy a few files from local to dfs and you are all set.