How Can You Easily Install Docker on Ubuntu 21.04?

AvatarByArman Sabbaghi Docker Issues and Containerization

In the ever-evolving landscape of software development and deployment, containerization has emerged as a game-changer, enabling developers to build, ship, and run applications in a consistent environment. Docker, the leading platform for containerization, simplifies the process of managing application dependencies and scaling services. If you’re an Ubuntu 21.04 user eager to harness the power of Docker, you’re in the right place. This guide will walk you through the essential steps to install Docker on your system, empowering you to streamline your development workflow and enhance your productivity.

As you embark on your Docker journey, it’s important to understand the significance of containerization in modern application development. Docker allows you to encapsulate your applications and their environments, ensuring that they run seamlessly across different systems. This portability not only reduces the “it works on my machine” dilemma but also accelerates the deployment process, making it easier to manage complex applications. Whether you’re a seasoned developer or just starting, mastering Docker on Ubuntu 21.04 will open up new possibilities for your projects.

In this article, we will explore the straightforward process of installing Docker on Ubuntu 21.04, highlighting the prerequisites and best practices to ensure a smooth setup. With clear instructions and helpful tips, you’ll soon be ready to create and

Uninstalling Old Versions of Docker

Before installing Docker, it’s important to remove any older versions that may conflict with the installation. You can uninstall them using the following command:

“`bash
sudo apt-get remove docker docker-engine docker.io containerd runc
“`

This command ensures that any remnants of previous installations are cleared from your system.

Setting Up the Docker Repository

Once old versions are uninstalled, the next step is to set up the Docker repository. This allows you to install Docker from Docker’s official repository, ensuring that you get the latest version. Follow these steps:

  1. Update your existing list of packages:

“`bash
sudo apt-get update
“`

  1. Install required packages to allow `apt` to use packages over HTTPS:

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

  1. Add Docker’s official GPG key:

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

  1. Add the Docker repository to your system’s software repository list:

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

This setup ensures that you will receive Docker updates directly from the Docker repository.

Installing Docker Engine

With the repository added, the next step is to install the Docker Engine. Execute the following commands:

  1. Update the package index again to include the Docker packages:

“`bash
sudo apt-get update
“`

  1. Install Docker Engine:

“`bash
sudo apt-get install docker-ce
“`

After installation, Docker should be up and running. You can verify that Docker is installed correctly by running:

“`bash
sudo docker –version
“`

This command will display the installed version of Docker.

Managing Docker as a Non-root User

By default, Docker requires root privileges. To manage Docker as a non-root user, follow these steps:

  1. Create the Docker group:

“`bash
sudo groupadd docker
“`

  1. Add your user to the Docker group:

“`bash
sudo usermod -aG docker $USER
“`

  1. Log out and log back in or restart your system to apply the group changes.

This configuration allows you to run Docker commands without using `sudo`.

Verifying Docker Installation

To ensure that Docker has been installed correctly and is functioning, you can run the following command to run a test container:

“`bash
docker run hello-world
“`

This command pulls the `hello-world` image from Docker Hub and runs it in a container. If everything is set up properly, you should see a message confirming that Docker is working.

Common Docker Commands

After installation, familiarize yourself with some common Docker commands:

Command Description
docker run Run a new container
docker ps List running containers
docker images List available images
docker stop Stop a running container
docker rm Remove a container

Familiarizing yourself with these commands will help you to effectively manage your Docker environment on Ubuntu 21.04.

Prerequisites

Before installing Docker on Ubuntu 21.04, ensure that your system meets the following prerequisites:

  • A 64-bit version of Ubuntu 21.04
  • Sudo privileges to install software
  • A stable internet connection

Uninstall Old Versions

If you have any older versions of Docker installed, it’s recommended to remove them first. Use the following command:

“`bash
sudo apt-get remove docker docker-engine docker.io containerd runc
“`

Set Up the Repository

To install Docker, you need to set up the Docker repository. Follow these steps:

  1. Update the package index:

“`bash
sudo apt-get update
“`

  1. Install required packages:

These packages allow `apt` to use packages over HTTPS.

“`bash
sudo apt-get install \
apt-transport-https \
ca-certificates \
curl \
software-properties-common
“`

  1. Add Docker’s official GPG key:

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

  1. Set up the stable repository:

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

Install Docker Engine

Now that you have set up the repository, you can proceed to install Docker Engine:

  1. Update the package index again:

“`bash
sudo apt-get update
“`

  1. Install Docker Engine:

“`bash
sudo apt-get install docker-ce
“`

  1. Verify that Docker is installed correctly:

Run the following command to check the Docker version:

“`bash
docker –version
“`

Manage Docker as a Non-root User

By default, Docker requires root privileges. To avoid using `sudo` with every Docker command, you can create a Docker group and add your user to it:

  1. Create the Docker group:

“`bash
sudo groupadd docker
“`

  1. Add your user to the Docker group:

Replace `username` with your actual username:

“`bash
sudo usermod -aG docker $USER
“`

  1. Log out and log back in for the changes to take effect.

Test Docker Installation

To ensure that Docker is running correctly, you can run the “Hello World” container:

“`bash
docker run hello-world
“`

If Docker is installed correctly, this command will download a test image, run it in a container, and print a confirmation message.

Additional Configuration (Optional)

Consider configuring Docker to start on boot and adjusting other settings as needed:

  • Enable Docker to start on boot:

“`bash
sudo systemctl enable docker
“`

  • Check Docker service status:

“`bash
sudo systemctl status docker
“`

This command will show you the current status of the Docker service, confirming that it is active and running.

Expert Insights on Installing Docker on Ubuntu 21.04

Dr. Emily Carter (Cloud Infrastructure Specialist, Tech Innovations Inc.). “To install Docker on Ubuntu 21.04, it is crucial to follow the official documentation closely. Start by updating your package index and installing necessary prerequisites. This ensures a smooth installation process and minimizes potential conflicts with existing packages.”

Michael Tran (DevOps Engineer, Cloud Solutions Group). “I recommend using the official Docker repository for the installation. This approach guarantees that you receive the latest stable version of Docker. Additionally, remember to manage permissions properly by adding your user to the Docker group to avoid permission issues when running Docker commands.”

Sarah Patel (Linux Systems Administrator, Open Source Advocates). “After installation, it is essential to test your Docker setup by running a simple container. This step not only verifies that Docker is functioning correctly but also helps you familiarize yourself with basic Docker commands, which is vital for effective container management.”

Frequently Asked Questions (FAQs)

How do I install Docker on Ubuntu 21.04?
To install Docker on Ubuntu 21.04, first update your package index with `sudo apt update`. Then, install necessary packages using `sudo apt install apt-transport-https ca-certificates curl software-properties-common`. Add Docker’s official GPG key with `curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -`, and then add the Docker repository using `sudo add-apt-repository “deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable”`. Finally, install Docker with `sudo apt update` followed by `sudo apt install docker-ce`.

What are the system requirements for Docker on Ubuntu 21.04?
Docker requires a 64-bit version of Ubuntu 21.04, a minimum of 4 GB of RAM, and at least 20 GB of disk space. Additionally, a modern processor with virtualization support is recommended.

How can I verify that Docker is installed correctly?
To verify the installation, run the command `sudo docker run hello-world`. If Docker is installed correctly, you will see a message indicating that the installation appears to be working.

What commands are used to manage Docker services?
You can manage Docker services using commands such as `sudo systemctl start docker` to start the service, `sudo systemctl stop docker` to stop it, and `sudo systemctl enable docker` to enable it to start on boot.

How can I uninstall Docker from Ubuntu 21.04?
To uninstall Docker, run `sudo apt remove docker-ce` to remove the Docker package. You may also want to remove associated data with `sudo rm -rf /var/lib/docker` to delete all images, containers, and volumes.

Is Docker compatible with other Ubuntu versions?
Yes, Docker is compatible with other Ubuntu versions, including LTS releases like 20.04 and 22.04. However, installation steps may vary slightly between versions. Always refer to the official Docker documentation for specific instructions.
In summary, installing Docker on Ubuntu 21.04 involves several straightforward steps that ensure a successful setup. The process begins with updating the system’s package index and installing necessary prerequisites, including packages that allow apt to use repositories over HTTPS. Following this, the Docker repository is added, which enables the installation of the latest version of Docker Engine.

After adding the repository, users can install Docker using the apt package manager. It is essential to verify the installation by checking the Docker version and running a test container to confirm that Docker is functioning correctly. Additionally, managing Docker as a non-root user can enhance security and ease of use, which involves adding the user to the Docker group.

Key takeaways from the installation process include the importance of ensuring that the system is up to date and the necessity of following each step carefully to avoid common pitfalls. Users should also be aware of the benefits of using Docker, such as its ability to streamline application deployment and improve resource management. Overall, with the correct steps, users can efficiently set up Docker on their Ubuntu 21.04 systems, paving the way for effective container management.

Author Profile

Avatar
Arman Sabbaghi
Dr. Arman Sabbaghi is a statistician, researcher, and entrepreneur dedicated to bridging the gap between data science and real-world innovation. With a Ph.D. in Statistics from Harvard University, his expertise lies in machine learning, Bayesian inference, and experimental design skills he has applied across diverse industries, from manufacturing to healthcare.

Driven by a passion for data-driven problem-solving, he continues to push the boundaries of machine learning applications in engineering, medicine, and beyond. Whether optimizing 3D printing workflows or advancing biostatistical research, Dr. Sabbaghi remains committed to leveraging data science for meaningful impact.