Docker has become a standard tool for developing and deploying applications due to its ability to package applications into containers. Containers allow developers to bundle an application with all necessary dependencies into a standardized unit of software, making deployment and execution on any Linux system easier. This article will guide you through the steps of installing and setting up Docker on the CentOS 7 operating system.

Prerequisites

Before installing Docker, make sure your system meets the following requirements:

• Clean installation of CentOS 7
• Access to the root account or an account with sudo privileges

Step 1: Update System

First, update your system to ensure that all existing packages are upgraded to the latest versions. Open a terminal and run the following command:

sudo yum update -y

Step 2: Install Necessary Packages

Before installing Docker, you need to install several necessary packages that allow yum to use packages over HTTPS. Run the following command:

sudo yum install -y yum-utils device-mapper-persistent-data lvm2

Step 3: Add Docker Repository

Docker is not available in the default CentOS 7 repositories, so you need to add the official Docker repository. This will allow yum to find and install Docker. Run the following command:

sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

Step 4: Install Docker CE

After adding the Docker repository, you can install Docker Community Edition (CE) using yum. Run the following command:

sudo yum install docker-ce docker-ce-cli containerd.io -y

Step 5: Start Docker

After the installation is complete, start Docker using systemctl:

sudo systemctl start docker

To ensure Docker starts on system boot, use:

sudo systemctl enable docker

Step 6: Test the Installation

To verify that Docker has been successfully installed and started, run a Hello World container:

sudo docker run hello-world

If you see a message indicating that your Docker installation is working correctly, congratulations, you have successfully installed and started Docker on your CentOS 7!

Conclusion

Now that you have Docker installed on your CentOS 7 system, you can begin creating and managing Docker containers. Docker simplifies the development, testing, and deployment of applications by providing isolated environments for each application. For more information on working with Docker, visit the official Docker documentation.