:title: Requirements and Installation on Ubuntu Linux
:description: Please note this project is currently under heavy development. It should not be used in production.
:keywords: Docker, Docker documentation, requirements, virtualbox, vagrant, git, ssh, putty, cygwin, linux

.. _ubuntu_linux:

Ubuntu Linux
============

.. warning::

   These instructions have changed for 0.6. If you are upgrading from
   an earlier version, you will need to follow them again.

.. include:: install_header.inc

Right now, the officially supported distribution are:

- :ref:`ubuntu_precise`
- :ref:`ubuntu_raring`

Docker has the following dependencies

* Linux kernel 3.8 (read more about :ref:`kernel`)
* AUFS file system support (we are working on BTRFS support as an alternative)

Please read :ref:`ufw`, if you plan to use `UFW (Uncomplicated
Firewall) <https://help.ubuntu.com/community/UFW>`_

.. _ubuntu_precise:

Ubuntu Precise 12.04 (LTS) (64-bit)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

This installation path should work at all times.


Dependencies
------------

**Linux kernel 3.8**

Due to a bug in LXC, docker works best on the 3.8 kernel. Precise
comes with a 3.2 kernel, so we need to upgrade it. The kernel you'll
install when following these steps comes with AUFS built in. We also
include the generic headers to enable packages that depend on them,
like ZFS and the VirtualBox guest additions. If you didn't install the
headers for your "precise" kernel, then you can skip these headers for
the "raring" kernel. But it is safer to include them if you're not
sure.


.. code-block:: bash

   # install the backported kernel
   sudo apt-get update
   sudo apt-get install linux-image-generic-lts-raring linux-headers-generic-lts-raring

   # reboot
   sudo reboot


Installation
------------

.. warning::

   These instructions have changed for 0.6. If you are upgrading from
   an earlier version, you will need to follow them again.

Docker is available as a Debian package, which makes installation easy.


.. code-block:: bash

   # Add the Docker repository key to your local keychain
   # using apt-key finger you can check the fingerprint matches 36A1 D786 9245 C895 0F96 6E92 D857 6A8B A88D 21E9
   sudo sh -c "wget -qO- https://get.docker.io/gpg | apt-key add -"

   # Add the Docker repository to your apt sources list.
   sudo sh -c "echo deb http://get.docker.io/ubuntu docker main\
   > /etc/apt/sources.list.d/docker.list"

   # Update your sources
   sudo apt-get update

   # Install, you will see another warning that the package cannot be authenticated. Confirm install.
   sudo apt-get install lxc-docker

Verify it worked

.. code-block:: bash

   # download the base 'ubuntu' container and run bash inside it while setting up an interactive shell
   sudo docker run -i -t ubuntu /bin/bash

   # type 'exit' to exit


**Done!**, now continue with the :ref:`hello_world` example.

.. _ubuntu_raring:

Ubuntu Raring 13.04 (64 bit)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Dependencies
------------

**AUFS filesystem support**

Ubuntu Raring already comes with the 3.8 kernel, so we don't need to install it. However, not all systems
have AUFS filesystem support enabled, so we need to install it.

.. code-block:: bash

   sudo apt-get update
   sudo apt-get install linux-image-extra-`uname -r`


Installation
------------

Docker is available as a Debian package, which makes installation easy.

*Please note that these instructions have changed for 0.6. If you are upgrading from an earlier version, you will need
to follow them again.*

.. code-block:: bash

   # Add the Docker repository key to your local keychain
   # using apt-key finger you can check the fingerprint matches 36A1 D786 9245 C895 0F96 6E92 D857 6A8B A88D 21E9
   sudo sh -c "wget -qO- https://get.docker.io/gpg | apt-key add -"

   # Add the Docker repository to your apt sources list.
   sudo sh -c "echo deb http://get.docker.io/ubuntu docker main\
   > /etc/apt/sources.list.d/docker.list"

   # update
   sudo apt-get update

   # install
   sudo apt-get install lxc-docker


Verify it worked

.. code-block:: bash

   # download the base 'ubuntu' container
   # and run bash inside it while setting up an interactive shell
   sudo docker run -i -t ubuntu /bin/bash

   # type exit to exit


**Done!**, now continue with the :ref:`hello_world` example.


.. _ufw:

Docker and UFW
^^^^^^^^^^^^^^

Docker uses a bridge to manage container networking. By default, UFW
drops all `forwarding`, thus a first step is to enable UFW forwarding:

.. code-block:: bash

   sudo nano /etc/default/ufw
   ----
   # Change:
   # DEFAULT_FORWARD_POLICY="DROP"
   # to
   DEFAULT_FORWARD_POLICY="ACCEPT"

Then reload UFW:

.. code-block:: bash

   sudo ufw reload


UFW's default set of rules denied all `incoming`, so if you want to be
able to reach your containers from another host, you should allow
incoming connections on the docker port (default 4243):

.. code-block:: bash

   sudo ufw allow 4243/tcp

