How to Install Docker on Ubuntu 14.04 LTS

Step 1: Installation of Docker

First, you’ll follow a simple best practice: ensuring the list of available packages is up to date before installing anything new.

apt-get update

Let’s install Docker by installing the docker-io package:

apt-get -y install docker.io

Link and fix paths with the following two commands:

ln -sf /usr/bin/docker.io /usr/local/bin/docker

sed -i '$acomplete -F _docker docker' /etc/bash_completion.d/docker.io

Finally, and optionally, let’s configure Docker to start when the server boots:

update-rc.d docker.io defaults

Step 2: Download a Docker Container

Let’s begin using Docker! Download the fedora Docker image:

docker pull ubuntu

Step 3: Run a Docker Container

Now, to setup a basic ubuntu container with a bash shell, we just run one command.
docker run will run a command in a new container, -i attaches stdin and stdout,
-t allocates a tty, and we’re using the standard ubuntu container.

docker run -i -t ubuntu /bin/bash

That’s it! You’re now using a bash shell inside of a ubuntu docker container.

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

There are many community containers already available, which can be found through a search. In the command below I am searching for the keyword
debian:

docker search debian

Come From ：http://www.liquidweb.com/kb/how-to-install-docker-on-ubuntu-14-04-lts/