A quick note for installing Hadoop with CDH4 MapReduce v1 on Ubuntu.
Step 1: Add CDH4 repository
Create a new file /etc/apt/sources.list.d/cloudera.list with the following contents:
deb [arch=amd64] http://archive.cloudera.com/cdh4/<OS-release-arch><RELEASE>-cdh4 contrib
deb-src http://archive.cloudera.com/cdh4/<OS-release-arch><RELEASE>-cdh4 contrib
where: <OS-release-arch> is debian/squeeze/amd64/cdh, ubuntu/lucid/amd64/cdh, or ubuntu/precise/amd64/cdh, and <RELEASE> is the name of your distribution, which you can find by running lsb_release -c
For example: my box is …