The Easiest Guide: How to Install Docker on Ubuntu 22.04 & Run Your First Container

Want to learn how to install Docker on Ubuntu 22.04? This guide provides a simple, step-by-step approach to getting Docker up and running, even if you're a complete beginner. You'll learn how to install the Docker Engine, manage Docker as a non-root user, and run your first container.

Why Use Docker on Ubuntu?

Docker simplifies software deployment and management by using containers. These containers package applications and their dependencies, ensuring consistent performance across different environments. Using Docker on Ubuntu allows you to isolate applications, improving security and resource utilization.

Prerequisites for Installing Docker

Before diving in, make sure you have:

• An Ubuntu 22.04 server set up.
• A sudo non-root user.
• A basic understanding of the Linux command line.

Step 1: Installing Docker on Ubuntu 22.04

Let's get Docker installed using the official Docker repository for the latest version.

1. Update Package List: Start by updating your package lists to ensure you have the latest versions.

   sudo apt update
   

   Copy

2. Install Prerequisite Packages: Next, install the packages that allow apt to use repositories over HTTPS.

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

   Copy

3. Add Docker's GPG Key: Add the official GPG key to ensure the authenticity of the Docker packages.

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

   Copy

4. Add the Docker Repository Now, add the Docker repository to your APT sources.

   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
   

   Copy

5. Update Package List Again: Update your package lists to reflect the new repository.

   sudo apt update
   

   Copy

6. Verify Docker Installation Source It's a good practice to verify that you're installing from the Docker repository.

   apt-cache policy docker-ce
   

   Copy

   Confirm the installation candidate points to the Docker repository.

7. Finally, Install Docker: Install Docker Community Edition (CE) with:

   sudo apt install docker-ce
   

   Copy

Step 2: Manage Docker as a Non-Root User (Optional)

Running Docker commands without sudo is convenient. Here's how to configure it:

1. Add User to Docker Group: Add your user to the docker group.

   sudo usermod -aG docker ${USER}
   

   Copy

2. Apply Changes: Log out and back in or run the following command to apply the group membership changes.

   su - ${USER}
   

   Copy

3. Verify Group Membership: Confirm your user is in the docker group by typing:

   groups
   

   Copy

Step 3: Verify Docker Installation

Ensure Docker is running correctly by checking its status:

sudo systemctl status docker

A successful installation will show the service as active and running. With Docker successfully installed on Ubuntu, the next step is to check that you can download images.

Step 4: Running Your First Docker Container

Let's run a simple container to verify your Docker installation.

1. Run the 'hello-world' Image: This image tests your Docker setup.

   docker run hello-world
   

   Copy

   If everything is set up correctly, you'll see a message confirming a successful installation!

Step 5: Working with Docker Images

Docker images are the foundation of containers. Here’s how to manage them:

• Listing Images: See what images are available locally, use the command:

  docker images
  

  Copy

• Pulling Images: Download an image from Docker Hub using docker pull. For example, to pull the latest Ubuntu image:

  docker pull ubuntu:latest
  

  Copy

• Running Containers: Create and run a container from an image with:

   docker run -it ubuntu bash
  

  Copy

Understanding Docker Commands

Here's a quick reference to essential Docker commands:

• docker ps: List running containers.
• docker stop [container_id]: Stop a running container.
• docker rm [container_id]: Remove a stopped container.
• docker rmi [image_id]: Remove an image.

Securing Your Docker Installation on Ubuntu

Security should be a priority. Here are a few tips:

• Keep Docker Updated: Regularly update Docker to patch vulnerabilities.
• Use Docker Secrets: Manage sensitive information like passwords securely.
• Limit User Privileges: Avoid running containers as root.
• Implement a Firewall: Use UFW to control network traffic.

Conclusion

Congratulations! You've successfully installed and used Docker on Ubuntu 22.04. You now have the foundation to start containerizing applications and streamlining your development workflow. From here, explore Docker Compose for multi-container applications and consider container orchestration tools like Kubernetes for managing deployments at scale.