:title: Installation on Ubuntu :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 ====== .. 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 Docker is supported on the following versions of Ubuntu: - :ref:`ubuntu_precise` - :ref:`ubuntu_raring_saucy` Please read :ref:`ufw`, if you plan to use `UFW (Uncomplicated Firewall) `_ .. _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. **See the** :ref:`installmirrors` **section below if you are not in the United States.** Other sources of the Debian packages may be faster for you to install. First, check that your APT system can deal with ``https`` URLs: the file ``/usr/lib/apt/methods/https`` should exist. If it doesn't, you need to install the package ``apt-transport-https``. .. code-block:: bash [ -e /usr/lib/apt/methods/https ] || { apt-get update apt-get install apt-transport-https } Then, add the Docker repository key to your local keychain. .. code-block:: bash sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 36A1D7869245C8950F966E92D8576A8BA88D21E9 Add the Docker repository to your apt sources list, update and install the ``lxc-docker`` package. *You may receive a warning that the package isn't trusted. Answer yes to continue installation.* .. code-block:: bash sudo sh -c "echo deb https://get.docker.io/ubuntu docker main\ > /etc/apt/sources.list.d/docker.list" sudo apt-get update sudo apt-get install lxc-docker .. note:: There is also a simple ``curl`` script available to help with this process. .. code-block:: bash curl -s https://get.docker.io/ubuntu/ | sudo sh Now verify that the installation has worked by downloading the ``ubuntu`` image and launching a container. .. code-block:: bash sudo docker run -i -t ubuntu /bin/bash Type ``exit`` to exit **Done!**, now continue with the :ref:`hello_world` example. .. _ubuntu_raring_saucy: Ubuntu Raring 13.04 and Saucy 13.10 (64 bit) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ These instructions cover both Ubuntu Raring 13.04 and Saucy 13.10. Dependencies ------------ **Optional 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. AUFS support is optional as of version 0.7, but it's still available as a driver and we recommend using it if you can. To make sure AUFS is installed, run the following commands: .. 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. .. warning:: 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. First add the Docker repository key to your local keychain. .. code-block:: bash sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 36A1D7869245C8950F966E92D8576A8BA88D21E9 Add the Docker repository to your apt sources list, update and install the ``lxc-docker`` package. .. code-block:: bash sudo sh -c "echo deb http://get.docker.io/ubuntu docker main\ > /etc/apt/sources.list.d/docker.list" sudo apt-get update sudo apt-get install lxc-docker Now verify that the installation has worked by downloading the ``ubuntu`` image and launching a container. .. code-block:: bash sudo docker run -i -t ubuntu /bin/bash Type ``exit`` to exit **Done!**, now continue with the :ref:`hello_world` example. Giving non-root access ---------------------- The ``docker`` daemon always runs as the root user, and since Docker version 0.5.2, the ``docker`` daemon binds to a Unix socket instead of a TCP port. By default that Unix socket is owned by the user *root*, and so, by default, you can access it with ``sudo``. Starting in version 0.5.3, if you (or your Docker installer) create a Unix group called *docker* and add users to it, then the ``docker`` daemon will make the ownership of the Unix socket read/writable by the *docker* group when the daemon starts. The ``docker`` daemon must always run as the root user, but if you run the ``docker`` client as a user in the *docker* group then you don't need to add ``sudo`` to all the client commands. As of 0.9.0, you can specify that a group other than ``docker`` should own the Unix socket with the ``-G`` option. .. warning:: The *docker* group (or the group specified with ``-G``) is root-equivalent; see :ref:`dockersecurity_daemon` details. **Example:** .. code-block:: bash # Add the docker group if it doesn't already exist. sudo groupadd docker # Add the connected user "${USER}" to the docker group. # Change the user name to match your preferred user. # You may have to logout and log back in again for # this to take effect. sudo gpasswd -a ${USER} docker # Restart the Docker daemon. sudo service docker restart Upgrade -------- To install the latest version of docker, use the standard ``apt-get`` method: .. code-block:: bash # update your sources list sudo apt-get update # install the latest sudo apt-get install lxc-docker Memory and Swap Accounting ^^^^^^^^^^^^^^^^^^^^^^^^^^ If want to enable memory and swap accounting, you must add the following command-line parameters to your kernel:: cgroup_enable=memory swapaccount=1 On systems using GRUB (which is the default for Ubuntu), you can add those parameters by editing ``/etc/default/grub`` and extending ``GRUB_CMDLINE_LINUX``. Look for the following line:: GRUB_CMDLINE_LINUX="" And replace it by the following one:: GRUB_CMDLINE_LINUX="cgroup_enable=memory swapaccount=1" Then run ``update-grub``, and reboot. Troubleshooting ^^^^^^^^^^^^^^^ On Linux Mint, the ``cgroup-lite`` package is not installed by default. Before Docker will work correctly, you will need to install this via: .. code-block:: bash sudo apt-get update && sudo apt-get install cgroup-lite .. _ufw: Docker and UFW ^^^^^^^^^^^^^^ Docker uses a bridge to manage container networking. By default, UFW drops all `forwarding` traffic. As a result you will need 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 denies all `incoming` traffic. If you want to be able to reach your containers from another host then you should allow incoming connections on the Docker port (default 4243): .. code-block:: bash sudo ufw allow 4243/tcp Docker and local DNS server warnings ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Systems which are running Ubuntu or an Ubuntu derivative on the desktop will use `127.0.0.1` as the default nameserver in `/etc/resolv.conf`. NetworkManager sets up dnsmasq to use the real DNS servers of the connection and sets up `nameserver 127.0.0.1` in `/etc/resolv.conf`. When starting containers on these desktop machines, users will see a warning: .. code-block:: bash WARNING: Local (127.0.0.1) DNS resolver found in resolv.conf and containers can't use it. Using default external servers : [8.8.8.8 8.8.4.4] This warning is shown because the containers can't use the local DNS nameserver and Docker will default to using an external nameserver. This can be worked around by specifying a DNS server to be used by the Docker daemon for the containers: .. code-block:: bash sudo nano /etc/default/docker --- # Add: DOCKER_OPTS="--dns 8.8.8.8" # 8.8.8.8 could be replaced with a local DNS server, such as 192.168.1.1 # multiple DNS servers can be specified: --dns 8.8.8.8 --dns 192.168.1.1 The Docker daemon has to be restarted: .. code-block:: bash sudo restart docker .. warning:: If you're doing this on a laptop which connects to various networks, make sure to choose a public DNS server. An alternative solution involves disabling dnsmasq in NetworkManager by following these steps: .. code-block:: bash sudo nano /etc/NetworkManager/NetworkManager.conf ---- # Change: dns=dnsmasq # to #dns=dnsmasq NetworkManager and Docker need to be restarted afterwards: .. code-block:: bash sudo restart network-manager sudo restart docker .. warning:: This might make DNS resolution slower on some networks. .. _installmirrors: Mirrors ^^^^^^^ You should ``ping get.docker.io`` and compare the latency to the following mirrors, and pick whichever one is best for you. Yandex ------ `Yandex `_ in Russia is mirroring the Docker Debian packages, updating every 6 hours. Substitute ``http://mirror.yandex.ru/mirrors/docker/`` for ``http://get.docker.io/ubuntu`` in the instructions above. For example: .. code-block:: bash sudo sh -c "echo deb http://mirror.yandex.ru/mirrors/docker/ docker main\ > /etc/apt/sources.list.d/docker.list" sudo apt-get update sudo apt-get install lxc-docker