Install Docker and Docker-Compose on Ubuntu

Introduction

In this tutorial, we will install and use Docker Community Edition (CE) and Docker Compose on Ubuntu. You’ll install Docker and Docker Compose and play with them.

Installing Docker

Docker is an application that simplifies 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, resource-friendly, and dependent on the host operating system.

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

Update your packages:

sudo apt update

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

sudo apt install apt-transport-https ca-certificates curl software-properties-common gnupg lsb-release

Add the GPG key for the official docker repository and add the repository to APT sources.

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu focal stable"

This will also update our package database with the Docker packages from the newly added repo.

Now install Docker:

sudo apt install docker-ce

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

sudo systemctl status docker

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

# Output
● docker.service - Docker Application Container Engine
     Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
     Active: active (running) since Sun 2022-07-31 12:02:24 CEST; 9h ago
TriggeredBy: ● docker.socket
       Docs: https://docs.docker.com
   Main PID: 1524 (dockerd)
      Tasks: 62
     Memory: 84.7M
        CPU: 29.678s
     CGroup: /system.slice/docker.service
             ├─1524 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock

Executing the Docker Command Without Sudo (Optional)

By default, the docker the command can only be run by 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 will get an error. If you want to avoid typing sudo whenever you run the docker command, add your username to the docker group:

sudo usermod -aG docker ${USER}

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

su - ${USER}

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

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

sudo usermod -aG docker username

To apply the new group membership:

su - username

Installing Docker Compose

Docker Compose is yet another useful Docker tool. It allows users to launch, execute, communicate, and close containers with a single coordinated command. Essentially, Docker Compose is used for defining and running multi-container Docker applications.

Start by updating the default repository:

sudo apt update

Download the latest docker-compose version using the command:

sudo curl -L "https://github.com/docker/compose/releases/download/v2.21.0/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose

The command instructs the system to save the file in the /usr/local/bin/ directory under the name docker-compose.

You can check the releases here.

Make the downloaded file executable by changing the file permission with:

sudo chmod +x /usr/local/bin/docker-compose

To verify the installation, check the Docker Compose version by running:

docker–compose --version

Docker Compose should now be installed and ready to use!

Mumuni Mohammed

Experienced DevOps Engineer proficient in Python, Docker, Kubernetes, CI/CD, and cloud technologies. Specialized in automating processes and building scalable infrastructure for seamless development and deployment.