Install Docker under Ubuntu 14.04 (Trusty)

Docker supports Ubuntu versions:

• Ubuntu Vivid 15.04 (64-bit)
• Ubuntu Trusty 14.04 (LTS) (64-bit)
• Ubuntu Precise 12.04 (LTS) (64-bit)
• Ubuntu Raring 13.04 and Saucy 13.10 (64 bit) 

For both Vivid and Trusty you need nothing. It will work out of the box. Others will require some modifications. (Updating of some things, like kernel or installing with wget on 13.04)

1. To install docker from a repository do so:

sudo apt-get update
sudo apt-get install docker.io
sudo ln -sf /usr/bin/docker.io /usr/local/bin/docker
sudo sed -i '$acomplete -F _docker docker' /etc/bash_completion.d/docker.io

2. Now run it with:

sudo apt-get install lxc-docker

3. Make it run on system boot:

sudo update-rc.d docker.io defaults

4. Ready to go! Run container with an Ubuntu:

sudo docker run -i -t ubuntu /bin/bash

To disconnect, or detach, from the shell without exiting use the escape sequence Ctrl-p + Ctrl-q.