How to install Docker in Ubuntu

To get started with Docker on Ubuntu, make sure you meet the prerequisites, then install Docker.

Prerequisites

OS requirements

To install Docker, you need the 64-bit version of one of these Ubuntu versions:

• Yakkety 16.10
• Xenial 16.04 (LTS)
• Trusty 14.04 (LTS)

Recommended extra packages for Trusty 14.04

Unless you have a strong reason not to, install the linux-image-extra-* packages, which allow Docker to use the aufs storage drivers.

$ sudo apt-get update

$ sudo apt-get install -y --no-install-recommends \ 
linux-image-extra-$(uname -r) \ 
linux-image-extra-virtual

Install Docker

You can install Docker in different ways, depending on your needs:

• Most users set up Docker’s repositories and install from them, for ease of installation and upgrade tasks. This is the recommended approach.
• Some users download the DEB package and install it manually and manage upgrades completely manually.
• Some users cannot use the official Docker repositories, and must rely on the version of Docker that comes with their operating system. This version of Docker may be out of date. Those users should consult their operating system documentation and not follow these procedures.

Install using the repository

Before you install Docker for the first time on a new host machine, you need to set up the Docker repository. Afterward, you can install, update, or downgrade Docker from the repository.

Set up the repository

1. Install packages to allow apt to use a repository over HTTPS:

   $ sudo apt-get install -y --no-install-recommends \ 
   apt-transport-https \ 
   ca-certificates \ 
   curl \ 
   software-properties-common

2. Add Docker’s official GPG key:

   $ curl -fsSL https://apt.dockerproject.org/gpg | sudo apt-key add -

   Verify that the key ID is 58118E89F3A912897C070ADBF76221572C52609D.

   $ apt-key fingerprint 58118E89F3A912897C070ADBF76221572C52609D

   pub 4096R/2C52609D 2015-07-14 Key 
         fingerprint = 5811 8E89 F3A9 1289 7C07 0ADB F762 2157 2C52 609D 
   uid Docker       Release Tool (releasedocker) <do****@do****.com>

3. Use the following command to set up the stable repository.
   

   Note: The lsb_release -cs sub-command below returns the name of your Ubuntu distribution, such as xenial.

   $

   sudo add-apt-repository \ 
   "deb https://apt.dockerproject.org/repo/ \ 
   ubuntu-$(lsb_release -cs) \ 
   main"

   To enable the testing repository, you can edit /etc/apt/sources.list and add the word testing after main on the appropriate line of the file. Do not use unstable repositories on production systems or for non-testing workloads.

   Note: Sometimes, in a distribution like Linux Mint, you might have to change ubuntu-$(lsb_release -cs) to your parent Ubuntu distribution. example: If you are using Linux Mint Rafaela, you could type in ubuntu-trusty

Install Docker

1. Update the apt package index.

   $ sudo apt-get update

2. Install the latest version of Docker, or go to the next step to install a specific version. Any existing installation of Docker is replaced.Use this command to install the latest version of Docker:

   $ sudo apt-get -y install docker-engine

   Warning: If you have both stable and unstable repositories enabled, installing or updating without specifying a version in the apt-get install or apt-get update command will always install the highest possible version, which will almost certainly be an unstable one.

3. On production systems, you should install a specific version of Docker instead of always using the latest. This output is truncated. List the available versions.

   $ apt-cache madison docker-engine

   docker-engine | 1.13.0-0~ubuntu-xenial | https://apt.dockerproject.org/repo ubuntu-xenial/main amd64 Packages 
   docker-engine | 1.12.6-0~ubuntu-xenial | https://apt.dockerproject.org/repo ubuntu-xenial/main amd64 Packages 
   docker-engine | 1.12.5-0~ubuntu-xenial | https://apt.dockerproject.org/repo ubuntu-xenial/main amd64 Packages 
   docker-engine | 1.12.4-0~ubuntu-xenial | https://apt.dockerproject.org/repo ubuntu-xenial/main amd64 Packages

   The contents of the list depend upon which repositories are enabled, and will be specific to your version of Ubuntu (indicated by the xenial suffix on the version, in this example). Choose a specific version to install. The second column is the version string. The third column is the repository name, which indicates which repository the package is from and by extension its stability level. To install a specific version, append the version string to the package name and separate them by an equals sign (=):

   $ sudo apt-get -y install docker-engine=<VERSION_STRING>

   The Docker daemon starts automatically.

4. Verify that docker is installed correctly by running the hello-world image.

   $ sudo docker run hello-world

   This command downloads a test image and runs it in a container. When the container runs, it prints an informational message and exits.

Docker is installed and running. You need to use sudo to run Docker commands. Continue to Linux postinstall to allow non-privileged users to run Docker commands and for other optional configuration steps.

Upgrade Docker

To upgrade Docker, first run sudo apt-get update, then follow the installation instructions, choosing the new version you want to install.

Install from a package

If you cannot use Docker’s repository to install Docker, you can download the .deb file for your release and install it manually. You will need to download a new file each time you want to upgrade Docker.

1. Go to https://apt.dockerproject.org/repo/pool/main/d/docker-engine/ and download the .deb file for the Docker version you want to install and for your version of Ubuntu.
   

   Note: To install a testing version, change the word main in the URL to testing. Do not use unstable versions of Docker in production or for non-testing workloads.

2. Install Docker, changing the path below to the path where you downloaded the Docker package.

   $ sudo dpkg -i /path/to/package.deb

   The Docker daemon starts automatically.

3. Verify that docker is installed correctly by running the hello-world image.

   $ sudo docker run hello-world

   This command downloads a test image and runs it in a container. When the container runs, it prints an informational message and exits.

Docker is installed and running. You need to use sudo to run Docker commands. Continue to Post-installation steps for Linux to allow non-privileged users to run Docker commands and for other optional configuration steps.

Upgrade Docker

To upgrade Docker, download the newer package file and repeat the installation procedure, pointing to the new file.

Uninstall Docker

1. Uninstall the Docker package:

   $ sudo apt-get purge docker-engine

2. Images, containers, volumes, or customized configuration files on your host are not automatically removed. To delete all images, containers, and volumes:

   $ sudo rm -rf /var/lib/docker

You must delete any edited configuration files manually.