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Docker in Linux

Docker in Linux

With Docker, developers can bid farewell to the complexities of managing software dependencies and embrace a streamlined and efficient approach. Docker is a phenomenal solution for Linux-based software development! As it has accelerated the way applications are created, deployed, and managed. In this blog, we’ll delve into the capabilities of Docker on Linux, empowering you to elevate your software development journey.

Kindly go through our explanation video in order to get a better understanding about Docker

What is Docker in Linux?

Docker is a valuable tool for Linux-based software development, offering a transformative approach to deploying applications. It leverages containerization technology to consolidate applications and their dependencies into self-contained units known as containers.

These containers possess the ability to function independently and are compatible with various Linux environments, ensuring uniform behavior across diverse setups. Docker streamlines the software development cycle by introducing a standardized framework for packaging, distributing, and deploying applications. 

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Why Use Docker?

Why Use Docker?

There are several benefits to using Docker in software development:

  • Portability: Docker allows applications to be packaged into self-contained units called containers. These containers are platform-independent and can run on any machine which has Docker installed, irrespective of the underlying operating system or infrastructure. This portability simplifies the deployment process and ensures consistent behavior across different environments.
  • Efficiency: Docker optimizes resource utilization by utilizing containerization technology. Containers are lightweight and share the host system’s kernel, resulting in faster startup times and lower resource overhead compared to traditional virtualization methods. Docker also enables efficient scaling of applications by quickly creating multiple instances of containers as needed.
  • Dependency Management: Docker simplifies managing application dependencies. By packaging the application along with its dependencies into a container, developers can ensure that the application runs consistently without conflicts or compatibility issues.
  • Isolation: Docker provides isolation between containers and the host system, ensuring that applications within containers cannot interfere with each other or with the underlying infrastructure. This isolation enhances security and stability, allowing multiple applications to run side-by-side without conflict.
  • Community: Docker has a large and active community of developers and a rich ecosystem of pre-built images available on Docker Hub. This empowers developers to leverage existing images, reducing the time and effort required to set up and configure application environments.

Learn more about Docker Tutorial for Beginners!

System Requirements to Install Docker in Linux

The system requirements to install Docker on Linux can vary depending on your distribution and version. However, here are the general recommended requirements:

  • Operating System:
    Docker Engine supports a wide range of Linux distributions. Some popular distributions include Ubuntu, Debian, CentOS, Fedora, and RHEL. Make sure your Linux distribution is officially supported by Docker.
  • Architecture:
    Docker supports x86_64 (64-bit), armhf (32-bit ARM), and arm64 (64-bit ARM) architectures. Ensure that your system’s architecture is compatible.
  • Kernel-Version:
    Docker requires a Linux kernel version of 3.10 or higher. You can check your kernel version by running the command:

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uname -r
  • CPU:
    Docker typically works well with modern CPUs. However, virtualization extensions (e.g., Intel VT-x or AMD-V) need to be enabled in the BIOS/UEFI firmware for optimal performance.
  • RAM:
    Docker recommends a minimum of 2 GB of RAM for the host system. However, depending on your use case and the number of containers you plan to run, you may need more RAM.
  • Disk Space:
    Docker requires disk space to store containers, images, and other data. The recommended minimum disk space is 20 GB. Additionally, consider allocating additional space if you plan to work with large images or data volumes.

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How to Install Docker in Linux?

How to Install Docker in Linux?

To install Docker in Linux, follow these step-by-step instructions:

  1. Update System Packages:
    Open a terminal window and update the package lists for upgrades and new package installations. Use the following command:
sudo apt update
  1. Install Required Dependencies:
    Docker requires some dependencies to be installed. Run the following command to install these dependencies:
sudo apt install apt-transport-https ca-certificates curl software-properties-common
  1. Add Docker’s GPG Key:
    Import Docker’s official GPG key to ensure the authenticity of Docker packages during installation. Enter the following command to download and add the key:
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg
  1. Add a Docker Repository:
    Add the Docker repository to your system’s software sources list. Run the command below to add the repository:
echo "deb [arch=amd64signed-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
  1. Update Package Lists Again:
    Run the update command once more to include the newly added Docker repository:
sudo apt update
  1. Install Docker:
    Finally, you can install Docker by running the following command:
sudo apt install docker-ce docker-ce-cli containerd.io
  1. Start and Enable Docker Service:
    After the installation is complete, start the Docker service and enable it to start on boot. Execute the following commands:
sudo systemctl start docker
sudo systemctl enable docker
  1. Verify Docker Installation:
    To confirm that Docker is installed correctly, run a simple “Hello World” container by entering the following command:
sudo docker run hello-world

If Docker is properly installed, you will see a message confirming its installation and functionality.

Congratulations! Docker is now successfully installed on your Linux system.

Ready to get started? Visit our blog for a detailed guide on how to install docker on ubuntu.

Creating a Container in Docker in Linux

To create a container in Docker in Linux, follow the following steps:

  • Create a Dockerfile:
    Create a file called “Dockerfile” (without any file extension) in a directory of your choice. Open the file and add the following content:
FROM ubuntu:latest
CMD echo "Hello, Docker!"

This Dockerfile specifies that we want to use the latest Ubuntu base image and run a command to echo “Hello, Docker!” when the container starts.

  • Build the Docker Image:
    Open a terminal and navigate to the directory where you saved the Dockerfile. Run the following command to build the Docker image:
docker build -t my-container 

This command tells Docker to build an image based on the Dockerfile in the current directory and tag it with the name “my-container”.

  • Run the Docker Container:
    Once the image is built, you can run a container based on that image using the following command:
docker run my-container

Docker will start a container from the image and execute the command specified in the Dockerfile (echo “Hello, Docker!”). You should see the output “Hello, Docker!” printed in the terminal.

That’s it! You’ve created and run a simple Docker container on Linux. This example demonstrates the basic concept of using a Dockerfile to define the container’s configuration and behavior, building an image from the Dockerfile, and running a container based on that image. You can modify the Dockerfile to include additional instructions, dependencies, or custom applications as per your requirements.

Do checkout our blog on top features of linux operating system to gain in-depth knowledge about it!

Conclusion   

Docker is a valuable asset for Linux users, transforming the application deployment and management landscape. Docker streamlines the deployment process, fostering scalability improvements and facilitating seamless collaboration among development teams. The ecosystem and robust community backing have solidified Docker’s position as the preferred choice for Linux software containerization. Docker has brought about a significant paradigm shift in Linux-based application development and deployment practices.

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About the Author

Application Architect

Rupinder is a certified IT expert in AWS and Azure, working as a DevOps Architect and specializing in cloud and infrastructure. He designs and builds entire IT setups for important apps in banking, insurance, and finance.