6-2 Docker Installation

Learning Objectives

After completing this chapter, you will understand the basic concepts of Docker and its importance in modern software development. You will master the complete installation process of Docker on a Linux system—from preparing the system to verifying a successful installation. Additionally, you will learn how to troubleshoot common installation issues and perform basic post-installation configurations and operations. This knowledge will provide a solid foundation for your further study of container technologies.

System Requirements

Before installing Docker, ensure your Linux system meets the following requirements:-

- 64-bit processor

- Linux kernel version 3.10 or higher

- At least 4GB of RAM

Docker Installation Steps on Linux

1. Add Docker’s Official GPG Key

sudo apt update

sudo apt install ca-certificates curl

sudo install -m 0755 -d /etc/apt/keyrings

sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc

sudo chmod a+r /etc/apt/keyrings/docker.asc

2. Set Up the Stable Repository

sudo tee /etc/apt/sources.list.d/docker.sources <
Types: deb

URIs: https://download.docker.com/linux/ubuntu

Suites: $(. /etc/os-release && echo "${UBUNTU_CODENAME:-$VERSION_CODENAME}")

Components: stable

Signed-By: /etc/apt/keyrings/docker.asc

EOF
sudo apt update

3. Install Docker Engine

sudo apt-get install -y docker-ce=5:27.5* docker-ce-cli=5:27.5* containerd.io docker-buildx-plugin docker-compose-plugin --allow-downgrades

4. Verify Installation

Run the following command to confirm Docker is installed successfully:

sudo docker ps

sudo docker images

Graphic confirming that OpenCV is successfully installed on the system

5. Set User Permissions (Optional)
To run Docker as a non-root user, add your user to the Docker group:

sudo usermod -aG docker $USER

newgrp docker

Common Troubleshooting

1. GPG Key Error During Installation
Try re-adding the key:

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 

2. Docker Daemon Not Starting
Check the Docker service status:

sudo systemctl status docker

If it’s not running, try:

sudo systemctl start docker

Post-Installation Recommendations

1. Regularly update Docker: sudo apt-get upgrade docker-ce

2. Enable Docker to start on boot: sudo systemctl enable docker

3. Check Docker version: docker version

4. View Docker system info: docker info

After completing these steps, your system will have Docker installed and ready for container-based development and deployment.