Background

The following steps outline how to install Docker Engine on Ubuntu.

Requirements

• OS
  • Ubuntu Impish 21.10
  • Ubuntu Hirsute 21.04
  • Ubuntu Focal 20.04 (LTS)
  • Ubuntu Bionic 18.04 (LTS)

Installation

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

Setup the Repo

Run the following commands to prepare:^[1]

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$ sudo apt-get update
$ sudo apt-get install \
ca-certificates \
curl \
gnupg \
lsb-release

Add Docker’s official GPG key:

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$ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg

Configure the repo:

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$ echo \
"deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu \
$(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

Install the Docker Engine

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$ sudo apt-get update
$ sudo apt-get install docker-ce docker-ce-cli containerd.io

Post-Install Configuration

Once that completes, run the following commands to allow docker to run as non-root:^[2]

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$ sudo groupadd docker
$ sudo usermod -aG docker $USER
$ newgrp docker 

Sources