How to Install Docker on Ubuntu, CentOS, and Windows

What is Docker?

Docker is a containerization platform that allows you to package applications and their dependencies into lightweight, portable containers. These containers can run consistently across different environments, from development laptops to production servers.

Docker containers are similar to virtual machines but much more efficient. They share the host OS kernel and use fewer resources while providing the same isolation benefits.

Prerequisites

Before installing Docker, ensure you have:

• A 64-bit operating system
• Administrative/root access to your system
• At least 4GB of RAM (8GB recommended)
• Virtualization enabled in BIOS (for Windows)

Installing Docker on Ubuntu

Ubuntu provides an easy way to install Docker using the official Docker repository. This method ensures you get the latest version with security updates.

1. Update Package Index

   First, update your existing list of packages:

   TerminalCopy

   sudo apt update

2. Install Prerequisites

   Install packages that allow apt to use repositories over HTTPS:

   TerminalCopy

   sudo apt install apt-transport-https ca-certificates curl gnupg lsb-release

3. Add Docker's GPG Key

   Add Docker's official GPG key:

   TerminalCopy

   curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg

4. Add Docker Repository

   Set up the stable repository:

   TerminalCopy

   echo "deb [arch=amd64 signed-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

5. Install Docker Engine

   Update the apt package index and install Docker Engine:

   TerminalCopy

   sudo apt update
   sudo apt install docker-ce docker-ce-cli containerd.io

6. Add User to Docker Group

   Add your user to the docker group to run Docker without sudo:

   TerminalCopy

   sudo usermod -aG docker $USER

   Note: Log out and back in for this change to take effect.

Installing Docker on CentOS

CentOS installation is similar to Ubuntu but uses yum/dnf package manager instead of apt.

1. Remove Old Versions

   Remove any older versions of Docker:

   TerminalCopy

   sudo yum remove docker docker-client docker-client-latest docker-common docker-latest docker-latest-logrotate docker-logrotate docker-engine

2. Install Required Packages

   Install the yum-utils package:

   TerminalCopy

   sudo yum install -y yum-utils

3. Add Docker Repository

   Set up the Docker repository:

   TerminalCopy

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

4. Install Docker Engine

   Install Docker Engine, containerd, and Docker Compose:

   TerminalCopy

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

5. Start Docker Service

   Start and enable Docker service:

   TerminalCopy

   sudo systemctl start docker
   sudo systemctl enable docker

Installing Docker on Windows

Docker Desktop for Windows provides an easy way to run Docker on Windows 10/11 with WSL 2 (Windows Subsystem for Linux) backend.

1. System Requirements

   Ensure your system meets the requirements:

   • Windows 10 64-bit: Pro, Enterprise, or Education (Build 16299 or later)
   • Windows 11 64-bit: Home or Pro version 21H2 or higher
   • WSL 2 feature enabled
   • Virtualization enabled in BIOS
   • At least 4GB RAM

2. Enable WSL 2

   Open PowerShell as Administrator and run:

   PowerShell (Admin)Copy

   wsl --install

   Restart your computer when prompted.

3. Download Docker Desktop

   Visit docker.com/docker-desktopand download Docker Desktop for Windows.

4. Install Docker Desktop

   Run the installer and follow the installation wizard. Make sure to:

   • Enable "Use WSL 2 instead of Hyper-V" option
   • Add shortcut to desktop (optional)

5. Start Docker Desktop

   Launch Docker Desktop from the Start menu. It may take a few minutes to start the first time as it sets up the WSL 2 integration.

Verify Installation

After installing Docker, verify that it's working correctly by running a test container:

docker --version

You should see output similar to:

Docker version 24.0.7, build afdd53b

Now run the hello-world container to verify Docker is working:

docker run hello-world

This command downloads a test image and runs it in a container. If successful, you'll see a "Hello from Docker!" message.

Basic Docker Commands

Now that Docker is installed, here are some essential commands to get you started:

Container Management

# List running containers
docker ps

# List all containers (including stopped)
docker ps -a

# Run a container
docker run nginx

# Run a container in detached mode
docker run -d nginx

# Stop a container
docker stop <container_id>

# Remove a container
docker rm <container_id>

Image Management

# List images
docker images

# Pull an image from Docker Hub
docker pull ubuntu

# Remove an image
docker rmi <image_id>

# Build an image from Dockerfile
docker build -t myapp .

System Information

# Show Docker system information
docker info

# Show Docker disk usage
docker system df

# Clean up unused resources
docker system prune

Conclusion

Congratulations! You've successfully installed Docker on your system. Docker is now ready to help you containerize your applications and streamline your development workflow.

Next steps you might consider:

• Learn about Dockerfile and how to create custom images
• Explore Docker Compose for multi-container applications
• Set up a container registry for your images
• Learn about Docker networking and volumes
• Explore container orchestration with Kubernetes