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Docker Installation

Introduction​

Docker is a platform that enables developers to build, package, and run applications in containers. Containers are lightweight, portable, and consistent environments that include everything needed to run an application: code, runtime, system tools, libraries, and settings.

Before you can start creating and managing containers, you need to install Docker on your system. This guide walks you through the installation process for different operating systems and helps you verify your installation.

Prerequisites​

Before installing Docker, ensure your system meets the following requirements:

  • For Windows: Windows 10 64-bit: Pro, Enterprise, or Education (Build 16299 or later)
  • For macOS: macOS must be version 10.14 or newer (Mojave, Catalina, Big Sur, or later)
  • For Linux: A 64-bit version of Ubuntu, Debian, Fedora, or CentOS

You'll also need:

  • Administrative/sudo privileges on your machine
  • Internet connection for downloading Docker
  • Basic familiarity with command-line interfaces

Installing Docker on Windows​

Windows users have two options for installing Docker:

  1. Docker Desktop for Windows (recommended for most users)
  2. Docker Engine with WSL2 (for advanced users)

Option 1: Installing Docker Desktop for Windows​

  1. Download Docker Desktop from the official Docker website

  2. Double-click the installer and follow the installation wizard

  3. During installation, you'll be prompted to enable WSL 2 (Windows Subsystem for Linux) - it's recommended to enable this feature

  4. After installation completes, Docker will start automatically

  5. Verify the installation by opening a command prompt and running:

    cmd
    docker --version
    docker run hello-world

If you see the Docker version and a welcome message from the hello-world container, the installation was successful.

Option 2: Docker with WSL2 (Advanced)​

For users who prefer a more Linux-native experience, you can:

  1. Install WSL2 following the Microsoft documentation

  2. Install a Linux distribution like Ubuntu from the Microsoft Store

  3. Open your Linux distribution and install Docker Engine directly:

    bash
    sudo apt update
    sudo apt install docker.io
    sudo systemctl start docker
    sudo systemctl enable docker

  4. Configure Docker to start on boot:

    bash
    sudo systemctl enable docker

Installing Docker on macOS​

  1. Download Docker Desktop for Mac from the official Docker website

  2. Open the downloaded .dmg file and drag the Docker app to your Applications folder

  3. Open Docker from your Applications folder

  4. When prompted, enter your password to grant the necessary permissions

  5. Wait for Docker to start (you'll see the Docker icon in the menu bar)

  6. Verify the installation by opening Terminal and running:

    bash
    docker --version
    docker run hello-world

Installing Docker on Linux​

The installation process varies slightly depending on your Linux distribution. Here's how to install Docker on Ubuntu:

  1. Update your package index:

    bash
    sudo apt update

  2. Install packages to allow apt to use repositories over HTTPS:

    bash
    sudo apt install apt-transport-https ca-certificates curl software-properties-common

  3. Add Docker's official GPG key:

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

  4. Set up the stable repository:

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

  5. Update the apt package index again:

    bash
    sudo apt update

  6. Install Docker Engine:

    bash
    sudo apt install docker-ce docker-ce-cli containerd.io

  7. Verify the installation:

    bash
    sudo docker --version
    sudo docker run hello-world

Post-Installation Steps for Linux​

By default, Docker commands require sudo privileges. To run Docker without sudo, add your user to the Docker group:

bash
sudo usermod -aG docker $USER

Log out and log back in for the changes to take effect. After that, you can run Docker commands without sudo:

bash
docker run hello-world

Verifying Your Installation​

Regardless of your operating system, you can verify your Docker installation by running:

bash
docker --version

This should display the installed Docker version. Additionally, try running a test container:

bash
docker run hello-world

You should see output similar to:

Hello from Docker!
This message shows that your installation appears to be working correctly.
...

Docker Architecture Overview​

Now that you have Docker installed, let's understand the basic architecture:

  • Docker Client: The command-line interface you interact with
  • Docker Daemon: The background service that manages Docker objects
  • Images: Read-only templates used to create containers
  • Containers: Runnable instances of images
  • Registry: A repository of Docker images (like Docker Hub)

Basic Docker Commands​

Now that Docker is installed, here are some basic commands to get you started:

  1. Check Docker version:

    bash
    docker --version

  2. List all running containers:

    bash
    docker ps

  3. List all containers (including stopped ones):

    bash
    docker ps -a

  4. List available Docker images:

    bash
    docker images

  5. Run a container:

    bash
    docker run -d -p 80:80 nginx

    This runs an Nginx web server in the background, mapping port 80 of the container to port 80 on your host.

  6. Stop a container:

    bash
    docker stop container_id

Troubleshooting Common Installation Issues​

Docker Desktop Won't Start​

Windows:

  • Ensure Hyper-V and Virtualization are enabled in BIOS
  • Check that WSL2 is properly installed and configured

macOS:

  • Check for macOS updates
  • Ensure you have enough disk space
  • Try resetting Docker to factory settings through the menu

Permission Denied​

On Linux, if you see errors like "permission denied":

bash
Got permission denied while trying to connect to the Docker daemon socket

Ensure you've added your user to the docker group:

bash
sudo usermod -aG docker $USER

Then log out and log back in, or run:

bash
newgrp docker

Docker Engine Won't Start​

If the Docker service won't start:

bash
sudo systemctl status docker

Look for error messages in the output, then try:

bash
sudo systemctl restart docker

Summary​

In this guide, you've learned:

  • How to install Docker on Windows, macOS, and Linux
  • How to verify your installation
  • Basic Docker architecture
  • Essential Docker commands to get started
  • How to troubleshoot common installation issues

With Docker successfully installed, you're now ready to start creating and managing containers. In the next section of Docker Fundamentals, you'll learn how to work with Docker images and containers.

Additional Resources​

To deepen your understanding of Docker:

Practice Exercises​

  1. Install Docker on your system and verify the installation.
  2. Run the hello-world container and analyze the output.
  3. Find and run a public Nginx container, then access the default webpage through your browser.
  4. List all running containers and then stop the Nginx container.
  5. Explore Docker Hub and identify three images you might find useful for your projects.

If you spot any mistakes on this website, please let me know at [email protected]. I’d greatly appreciate your feedback! :)