1. If you have not configured anything extra, then docker needs root to work. By default, the docker daemon listens on a local Unix socket called 'docker.sock' in /var/run which is owned by the user root.
I have prepared a step by step guide to build spark project using scala in eclipse. We will run this application locally through eclipse and also run this in hdfs. You might have already guessed. Yes, you are correct we will work on WordCount as an example. After all we do not want to be an outliers by working on something else.
So, let's get started. I am assuming you already have spark set up and running. If not, you can download cloudera quick start VM from http://www.cloudera.com/downloads.html. I would recommend this if you do not have anything set up and running, cause this is easy and quick.
Go to http://www.ubuntu.com/download/desktop and download Ubuntu 14.04.4LTS. You want to download 64 bit version unless you are using something from your grandfather's age. It will take a while to download.