Setting up Docker in Ubuntu

Note: The following steps are for installing Docker from the Docker repository instead of the default Ubuntu repository.

1. Uninstall any old versions of Docker:

sudo apt-get remove docker docker-engine docker.io

2. Update the software repositories:

sudo apt-get update

3. Install a few necessary packages that allow apt to access repositories over HTTPS:

sudo apt-get install apt-transport-https ca-certificates curl gnupg-agent software-properties-common

The purpose of these packages are:

• apt-transport-https: Allows APT package manager to access repositories over HTTPS
• ca-certificates: Allows the web browser and system to check security certificates
• curl: A tool for transferring data
• gnupg-agent: An agent that manages private keys
• software-properties-common: Adds scripts for managing software

4. Add Docker’s official GPG key:

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

An OK response is expected.

5. Add Docker’s repository to APT sources:

sudo add-apt-repository \
   "deb [arch=amd64] https://download.docker.com/linux/ubuntu \
   $(lsb_release -cs) \
   stable"

6. Update the package database:

sudo apt-get update

7. Verify the version of the package docker-ce:

apt-cache policy docker-ce

A correct output will be as follow. Do note that the version number may differ.

8. Install the latest version of Docker:

sudo apt-get install docker-ce

Note: To install other version, use this command instead: sudo apt-get install docker-ce=<VERSION_STRING>, where an example of <VERSION_STRING> is 5:19.03.12~3–0~ubuntu-bionic.

9. Verify that Docker is running successfully:

sudo docker run hello-world

You will expect to see the following: