• Prerequisites
• Installing Required Dependencies
• Setting Up the Docker Repository
• Installing Docker Engine
• Starting and Enabling Docker
• Adding Your User to the Docker Group
• Testing Docker Installation
• Keeping Docker Updated
• Troubleshooting Common Issues
• Conclusion

Installing Docker on AlmaLinux 9.4 can significantly enhance your development and deployment processes by providing a reliable platform for containerization. This guide will walk you through the steps needed to set up Docker on this popular Linux distribution, ensuring you can leverage its powerful capabilities for your projects.

Prerequisites

Before starting the installation, it’s crucial to ensure your system is up-to-date and meets the necessary requirements:

1. AlmaLinux 9.4: Ensure you have AlmaLinux 9.4 installed.
2. Root Access: You need root or sudo privileges to install software packages.
3. Internet Connection: A stable internet connection is required to download Docker packages.

To begin, update your system packages to the latest versions by executing the following commands:

sudo dnf update -y

Installing Required Dependencies

Docker installation requires a few dependencies that may not be included in a default installation. Install them by running:

sudo dnf install -y yum-utils

This command installs yum-utils, which provides a set of utilities for managing repositories and packages.

Setting Up the Docker Repository

Next, add the official Docker repository to your system:

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

Even though we’re using AlmaLinux, this repository is compatible because AlmaLinux is a binary-compatible fork of CentOS.

Installing Docker Engine

Once the repository is added, you can now install Docker Engine. Use the following command:

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

This command will fetch and install Docker along with its command-line interface and container runtime.

Starting and Enabling Docker

After installation, you need to start the Docker service and enable it to start on boot. Execute the following commands:

sudo systemctl start docker
sudo systemctl enable docker

To verify that Docker is running correctly, you can check its status with:

sudo systemctl status docker

You should see output indicating that the Docker service is active and running.

Adding Your User to the Docker Group

For convenience, you may want to run Docker commands without needing to prefix them with sudo. To do this, add your user to the Docker group:

sudo usermod -aG docker $USER

After executing this command, log out and log back in, or restart your system to apply the group changes.

Testing Docker Installation

To confirm that Docker has been installed correctly and is functioning as expected, run the following command:

docker run hello-world

This command will pull a test image from Docker Hub and run it in a container. If everything is set up correctly, you’ll see a message that confirms Docker is running well on your system.

Keeping Docker Updated

To maintain security and functionality, periodically check for updates to Docker. Use the following command to update Docker in the future:

sudo dnf upgrade docker-ce

Troubleshooting Common Issues

• Docker Not Starting: If Docker fails to start, check the logs using journalctl -u docker.service for any error messages.
• Permission Denied: If you encounter permission issues while running Docker commands, ensure your user is part of the Docker group.

Conclusion

Installing Docker on AlmaLinux 9.4 opens the door to advanced application deployment and container management. With the above steps, you can set up a robust containerization environment tailored to your development needs. As you explore Docker, consider diving into its extensive documentation to understand its features better and enhance your workflows further. Whether you’re building microservices or simplifying your development process, Docker will serve as an invaluable tool in your software development toolkit.