Installing Docker on Ubuntu and CentOS

In this post I will follow the latest official docker steps to install docker engine from docker apt repository on Ubuntu and CentOS.

Installing docker engine on Ubuntu

I have spawned an Ubuntu server on cloud hosting and will connect with SSH to the machine. It is a fresh server of Ubuntu.

Uninstall old versions

As per the instructions we have to ensure that any conflicting packages are uninstalled.

for pkg in docker.io docker-doc docker-compose podman-docker containerd runc; do sudo apt-get remove $pkg; done

Set up the repository

1. Update the apt package index and install packages to allow apt to use a repository over HTTPS

sudo apt-get updatesudo apt-get install ca-certificates curl gnupg

2. Add Docker’s official GPG key:

sudo install -m 0755 -d /etc/apt/keyrings

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg

sudo chmod a+r /etc/apt/keyrings/docker.gpg

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

echo \

"deb [arch="$(dpkg --print-architecture)" signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu \

"$(. /etc/os-release && echo "$VERSION_CODENAME")" stable" | \

sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

Install Docker Engine

1. Update the apt package index:

 sudo apt-get update

2. Install Docker Engine, containerd, and Docker Compose latest version.

To install the latest version, run:

sudo apt-get install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

3. Verify that the Docker Engine installation is successful 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 a confirmation message and exits.

You have now successfully installed and started Docker Engine.

Installing docker on CentOS

I am using CentOS 8.3 to install Docker version 4.11. The CentOS VM is provisioned on Azure cloud. I will follow the recommended installation method to install from docker repository from official docker installation guide.

Prerequisites

Checking the pre-requisites required for docker to be installed on any environment.

yum-utils, device-mapper-persistent-data and lvm2

Setting up the Docker repo

Install the yum-utils package (which provides the yum-config-manager utility) and set up the repository.

sudo yum install -y yum-utils

sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

Install docker latest version

1- To install Docker Engine, containerd, and Docker Compose latest version run the below.

sudo yum install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

2- Start and enable docker service

sudo systemctl start docker

3- Run a hello-world image container to test the installation

sudo docker run hello-world