Install Docker En Ubuntu

Estimated reading time: 11 minutes

The following instructions will install Docker Engine on one of these supported Ubuntu and Debian releases: Supported distributions: Ubuntu 20.04, Ubuntu 18.04, Ubuntu 16.04, Debian 10, Debian 9. Recent non-LTS releases like Ubuntu 21.04 and 20.10 should also be supported. Install Docker Engine, 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. Verify that Docker Engine is installed correctly by running the hello-world image. $ sudo docker run hello-world. Sudo apt install docker-ce. This will install Docker, start the engine and configure it to always start on boot. After the installation is complete, verify that it is running. Sudo systemctl status docker. If installed successfully, the output will indicate that the service is active and running. Step 1: Update System. Ensure your system is updated. Sudo apt -y update Step 2: Install basic dependencies. There are few dependencies we need to configure Docker repositories and do the actual package installation. Sudo apt install docker-ce. At this point, you should now have successfully installed Docker from the official repository. Testing your new Docker Installation. With Docker now installed on your Ubuntu system, let us test it to ensure everything is working correctly. We will do this in two ways.

Scan your images for vulnerabilities

Using open source components in your container images can introduce vulnerabilities. Run docker scan to start securing your images using Snyk. If you have a Docker Pro, Team, or a Business subscription, you can automatically scan images when you push an image to Docker Hub. See Hub Vulnerability Scanning for more information.

To get started with Docker Engine on Ubuntu, make sure youmeet the prerequisites, theninstall Docker.

Prerequisites

OS requirements

To install Docker Engine, you need the 64-bit version of one of these Ubuntuversions:

  • Ubuntu Hirsute 21.04
  • Ubuntu Focal 20.04 (LTS)
  • Ubuntu Bionic 18.04 (LTS)

Docker Engine is supported on x86_64 (or amd64), armhf, arm64, and s390x architectures.

Ubuntu 16.04 LTS “Xenial Xerus” end-of-life

Ubuntu Linux 16.04 LTS reached the end of its five-year LTS window on April30th 2021 and is no longer supported. Docker no longer releases packages forthis distribution (including patch- and security releases). Users runningDocker on Ubuntu 16.04 are recommended to update their system to a currentlysupported LTS version of Ubuntu.

Uninstall old versions

Older versions of Docker were called docker, docker.io, or docker-engine.If these are installed, uninstall them:

It’s OK if apt-get reports that none of these packages are installed.

The contents of /var/lib/docker/, including images, containers, volumes, andnetworks, are preserved. If you do not need to save your existing data, and want tostart with a clean installation, refer to the uninstall Docker Enginesection at the bottom of this page.

Supported storage drivers

Docker Engine on Ubuntu supports overlay2, aufs and btrfs storage drivers.

Docker Engine uses the overlay2 storage driver by default. If you need to useaufs instead, you need to configure it manually.See use the AUFS storage driver

Installation methods

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

  • Most usersset up Docker’s repositories and installfrom them, for ease of installation and upgrade tasks. This is therecommended approach.

  • Some users download the DEB package andinstall it manually and manageupgrades completely manually. This is useful in situations such as installingDocker on air-gapped systems with no access to the internet.

  • In testing and development environments, some users choose to use automatedconvenience scripts to install Docker.

Install using the repository

Before you install Docker Engine for the first time on a new host machine, you needto set up the Docker repository. Afterward, you can install and update Dockerfrom the repository.

Set up the repository

  1. Update the apt package index and install packages to allow apt to use arepository over HTTPS:

  2. Add Docker’s official GPG key:

  3. Use the following command to set up the stable repository. To add thenightly or test repository, add the word nightly or test (or both)after the word stable in the commands below. Learn about nightly and test channels.

    Note: The lsb_release -cs sub-command below returns the name of yourUbuntu distribution, such as xenial. Sometimes, in a distributionlike Linux Mint, you might need to change $(lsb_release -cs)to your parent Ubuntu distribution. For example, if you are using Linux Mint Tessa, you could use bionic. Docker does not offer any guarantees on untestedand unsupported Ubuntu distributions.

Install Docker Engine

  1. Update the apt package index, and install the latest version of DockerEngine and containerd, or go to the next step to install a specific version:

    Got multiple Docker repositories?

    If you have multiple Docker repositories enabled, installingor updating without specifying a version in the apt-get install orapt-get update command always installs the highest possible version,which may not be appropriate for your stability needs.

  2. To install a specific version of Docker Engine, list the available versionsin the repo, then select and install:

    a. List the versions available in your repo:

    b. Install a specific version using the version string from the second column, for example, 5:18.09.1~3-0~ubuntu-xenial.

  3. Verify that Docker Engine is installed correctly by running the hello-worldimage.

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

Docker Engine is installed and running. The docker group is created but no usersare added to it. You need to use sudo to run Docker commands.Continue to Linux postinstall to allow non-privilegedusers to run Docker commands and for other optional configuration steps.

Upgrade Docker Engine

To upgrade Docker Engine, first run sudo apt-get update, then follow theinstallation instructions, choosing the newversion you want to install.

Install from a package

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

  1. Go to https://download.docker.com/linux/ubuntu/dists/,choose your Ubuntu version, then browse to pool/stable/, choose amd64,armhf, arm64, or s390x, and download the .deb file for the Docker Engineversion you want to install.

    Note

    To install a nightly or test (pre-release) package,change the word stable in the above URL to nightly or test.Learn about nightly and test channels.

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

    The Docker daemon starts automatically.

  3. Verify that Docker Engine is installed correctly by running the hello-worldimage.

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

Docker Engine is installed and running. The docker group is created but no usersare added to it. You need to use sudo to run Docker commands.Continue to Post-installation steps for Linux to allownon-privileged users to run Docker commands and for other optional configurationsteps.

Upgrade Docker Engine

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

Install using the convenience script

Docker provides a convenience script at get.docker.comto install Docker into development environments quickly and non-interactively.The convenience script is not recommended for production environments, but can beused as an example to create a provisioning script that is tailored to your needs.Also refer to the install using the repositorysteps to learn about installation steps to install using the package repository.The source code for the script is open source, and can be found in thedocker-install repository on GitHub.

Always examine scripts downloaded from the internet before running them locally.Before installing, make yourself familiar with potential risks and limitationsof the convenience script:

  • The script requires root or sudo privileges to run.
  • The script attempts to detect your Linux distribution and version andconfigure your package management system for you, and does not allow you tocustomize most installation parameters.
  • The script installs dependencies and recommendations without asking forconfirmation. This may install a large number of packages, depending on thecurrent configuration of your host machine.
  • By default, the script installs the latest stable release of Docker, containerd,and runc. When using this script to provision a machine, this may result inunexpected major version upgrades of Docker. Always test (major) upgrades ina test environment before deploying to your production systems.
  • The script is not designed to upgrade an existing Docker installation. Whenusing the script to update an existing installation, dependencies may not beupdated to the expected version, causing outdated versions to be used.

Tip: preview script steps before running

You can run the script with the DRY_RUN=1 option to learn what steps thescript will execute during installation:

This example downloads the script from get.docker.comand runs it to install the latest stable release of Docker on Linux:

Docker is installed. The docker service starts automatically on Debian baseddistributions. On RPM based distributions, such as CentOS, Fedora, RHEL or SLES,you need to start it manually using the appropriate systemctl or service command.As the message indicates, non-root users cannot run Docker commands by default.

Use Docker as a non-privileged user, or install in rootless mode?

The installation script requires root or sudo privileges to install anduse Docker. If you want to grant non-root users access to Docker, refer to thepost-installation steps for Linux.Docker can also be installed without root privileges, or configured to runin rootless mode. For instructions on running Docker in rootless mode, refer torun the Docker daemon as a non-root user (rootless mode).

How To Install Docker On Ubuntu

Install pre-releases

Docker also provides a convenience script at test.docker.comto install pre-releases of Docker on Linux. This script is equivalent to thescript at get.docker.com, but configures your package manager to enable the“test” channel from our package repository, which includes both stable andpre-releases (beta versions, release-candidates) of Docker. Use this script toget early access to new releases, and to evaluate them in a testing environmentbefore they are released as stable.

To install the latest version of Docker on Linux from the “test” channel, run:

Upgrade Docker after using the convenience script

If you installed Docker using the convenience script, you should upgrade Dockerusing your package manager directly. There is no advantage to re-running theconvenience script, and it can cause issues if it attempts to re-addrepositories which have already been added to the host machine.

Uninstall Docker Engine

  1. Uninstall the Docker Engine, CLI, and Containerd packages:

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

You must delete any edited configuration files manually.

Next steps

  • Continue to Post-installation steps for Linux.
  • Review the topics in Develop with Docker to learn how to build new applications using Docker.
requirements, apt, installation, ubuntu, install, uninstall, upgrade, update

In this tutorial, I will show how to install and use Docker Community Edition (CE) on Ubuntu 20.04.

Docker is an application that simplifies the process of managing application processes in containers. Containers let you run your applications in resource-isolated processes. They’re similar to virtual machines, but containers are more portable, more resource-friendly, and more dependent on the host operating system.

Installing Docker

The Docker installation package available in the official Ubuntu repository may not be the latest version. To ensure we get the latest version, we’ll install Docker from the official Docker repository. To do that, we’ll add a new package source, add the GPG key from Docker to ensure the downloads are valid, and then install the package.

First, update your existing list of packages:

Next, install a few prerequisite packages which let apt use packages over HTTPS:

Then add the GPG key for the official Docker repository to your system:

Add the Docker repository to APT sources:

Next, update the package database with the Docker packages from the newly added repo:

Make sure you are about to install from the Docker repo instead of the default Ubuntu repo:

You’ll see output like this, although the version number for Docker may be different: Output of apt-cache policy docker-ce

Notice that docker-ce is not installed, but the candidate for installation is from the Docker repository for Ubuntu 20.04 (focal).

Finally, install Docker:

Docker should now be installed, the daemon started, and the process enabled to start on boot. Check that it’s running:

The output should be similar to the following, showing that the service is active and running:

Install Docker En Ubuntu

Installing Docker now gives you not just the Docker service (daemon) but also the docker command line utility, or the Docker client. We’ll explore how to use the docker command later in this tutorial.

Executing the Docker Command Without Sudo

By default, the docker command can only be run the root user or by a user in the docker group, which is automatically created during Docker’s installation process. If you attempt to run the docker command without prefixing it with sudo or without being in the docker group, you’ll get an output like this:

If you want to avoid typing sudo whenever you run the docker command, add your username to the docker group:

Install Docker In Ubuntu Wsl

To apply the new group membership, log out of the server and back in, or type the following:

You will be prompted to enter your user’s password to continue.

Confirm that your user is now added to the docker group by typing:

If you need to add a user to the docker group that you’re not logged in as, declare that username explicitly using:

The rest of this article assumes you are running the docker command as a user in the docker group. If you choose not to, please prepend the commands with sudo.

Let’s explore the docker command next.

Install docker ubuntu wsl

Using the Docker Command

Using docker consists of passing it a chain of options and commands followed by arguments. The syntax takes this form:

To view all available subcommands, type:

As of Docker 19, the complete list of available subcommands will shown on terminal.

To view the options available to a specific command, type:

To view system-wide information about Docker, use:

Let’s explore some of these commands. We’ll start by working with images.

Working with Docker Images

Docker containers are built from Docker images. By default, Docker pulls these images from Docker-Hub, a Docker registry managed by Docker, the company behind the Docker project. Anyone can host their Docker images on Docker Hub, so most applications and Linux distributions you’ll need will have images hosted there.

To check whether you can access and download images from Docker Hub, type:

The output will indicate that Docker in working correctly:

Docker was initially unable to find the hello-world image locally, so it downloaded the image from Docker Hub, which is the default repository. Once the image downloaded, Docker created a container from the image and the application within the container executed, displaying the message.

You can search for images available on Docker Hub by using the docker command with the search subcommand. For example, to search for the Ubuntu image, type:

The script will crawl Docker Hub and return a listing of all images whose name match the search string. In this case, the output will be similar to this:

In the OFFICIAL column, OK indicates an image built and supported by the company behind the project. Once you’ve identified the image that you would like to use, you can download it to your computer using the pull subcommand.

Execute the following command to download the official ubuntu image to your computer:

You’ll see the following output:

After an image has been downloaded, you can then run a container using the downloaded image with the run subcommand. As you saw with the hello-world example, if an image has not been downloaded when docker is executed with the run subcommand, the Docker client will first download the image, then run a container using it.

To see the images that have been downloaded to your computer, type:

The output will look similar to the following:

As you’ll see later in this tutorial, images that you use to run containers can be modified and used to generate new images, which may then be uploaded (pushed is the technical term) to Docker Hub or other Docker registries.

Let’s look at how to run containers in more detail.

Running a Docker Container

The hello-world container you ran in the previous step is an example of a container that runs and exits after emitting a test message. Containers can be much more useful than that, and they can be interactive. After all, they are similar to virtual machines, only more resource-friendly.

As an example, let’s run a container using the latest image of Ubuntu. The combination of the -i and -t switches gives you interactive shell access into the container:

Your command prompt should change to reflect the fact that you’re now working inside the container and should take this form:

Install docker on ubuntu 20.04

Note the container id in the command prompt. In this example, it is d9b100f2f636. You’ll need that container ID later to identify the container when you want to remove it.

Now you can run any command inside the container. For example, let’s update the package database inside the container. You don’t need to prefix any command with sudo, because you’re operating inside the container as the root user:

Then install any application in it. Let’s install Node.js:

This installs Node.js in the container from the official Ubuntu repository. When the installation finishes, verify that Node.js is installed:

You’ll see the version number displayed in your terminal:

Any changes you make inside the container only apply to that container.

To exit the container, type exit at the prompt.

Let’s look at managing the containers on our system next.

Managing Docker Containers

After using Docker for a while, you’ll have many active (running) and inactive containers on your computer. To view the active ones, use:

You will see output similar to the following:

In this tutorial, you started two containers; one from the hello-world image and another from the ubuntu image. Both containers are no longer running, but they still exist on your system.

To view all containers — active and inactive, run docker ps with the -a switch:

You’ll see output similar to this:

To view the latest container you created, pass it the -l switch:

To start a stopped container, use docker start, followed by the container ID or the container’s name. Let’s start the Ubuntu-based container with the ID of 1c08a7a0d0e4:

Install Docker En Ubuntu Windows 7

The container will start, and you can use docker ps to see its status:

To stop a running container, use docker stop, followed by the container ID or name. This time, we’ll use the name that Docker assigned the container, which is quizzical_mcnulty:

Once you’ve decided you no longer need a container anymore, remove it with the docker rm command, again using either the container ID or the name. Use the docker ps -a command to find the container ID or name for the container associated with the hello-world image and remove it.

Install Docker En Ubuntu 18.04

You can start a new container and give it a name using the --name switch. You can also use the --rm switch to create a container that removes itself when it’s stopped. See the docker run help command for more information on these options and others.

Install Docker In Ubuntu 20

Thank you for reading this article.