Complete Docker Installation Guide for Ubuntu 22.04 & 24.04 LTS | 2025 Tutorial

Docker has become the industry standard for containerization, and installing it correctly on Ubuntu 22.04 and 24.04 LTS is crucial for modern development workflows. This comprehensive guide will walk you through the complete Docker installation process, covering everything from system requirements to post-installation configuration, ensuring you have a robust and secure Docker environment ready for production use.

Understanding Docker and Its Importance

Docker is a containerization platform that enables developers to package applications and their dependencies into lightweight, portable containers. These containers can run consistently across different environments, from development laptops to production servers. With Ubuntu’s Long Term Support (LTS) versions 22.04 (Jammy Jellyfish) and 24.04 (Noble Numbat), you get a stable foundation for running Docker workloads.

The containerization technology solves the “it works on my machine” problem by ensuring consistent runtime environments. Docker containers share the host OS kernel, making them more efficient than traditional virtual machines while providing excellent isolation and security.

Prerequisites and System Requirements

Supported Ubuntu Versions

Docker Engine supports the following Ubuntu versions with 64-bit architecture:

• Ubuntu 24.04 (Noble Numbat LTS) – Latest LTS release
• Ubuntu 22.04 (Jammy Jellyfish LTS) – Previous LTS release
• Ubuntu 24.10 (Oracular Oriole) – Latest standard release

Hardware Architecture Support

Docker Engine for Ubuntu is compatible with multiple architectures:

• x86_64 (amd64) – Most common for desktops and servers
• armhf – ARM 32-bit systems
• arm64 – ARM 64-bit systems (Raspberry Pi 4, Apple Silicon)
• s390x – IBM System z architecture
• ppc64le (ppc64el) – IBM POWER architecture

System Requirements

• 64-bit Ubuntu installation
• Minimum 2GB RAM (4GB recommended)
• At least 20GB free disk space
• Internet connection for downloading packages
• Sudo privileges or root access
• Updated package repositories

Important Firewall Considerations

Warning: If you use ufw or firewalld to manage firewall settings, be aware that when you expose container ports using Docker, these ports bypass your firewall rules. This is a critical security consideration that requires additional configuration.

Docker is only compatible with iptables-nft and iptables-legacy. Firewall rules created with nft are not supported on a system with Docker installed. Ensure any firewall rulesets use iptables or ip6tables and add them to the DOCKER-USER chain for proper packet filtering.

Step 1: Remove Conflicting Packages

Before installing the official Docker Engine, you must remove any unofficial Docker packages that might conflict with the installation. Ubuntu repositories may contain unofficial Docker packages that can cause issues.

Packages to Remove

The following unofficial packages must be uninstalled:

• docker.io – Unofficial Docker package from Ubuntu repos
• docker-compose – Standalone Docker Compose
• docker-compose-v2 – Docker Compose V2
• docker-doc – Docker documentation package
• podman-docker – Podman Docker compatibility layer
• containerd and runc – May conflict with Docker’s bundled versions

Removal Command

Execute the following command to remove all conflicting packages:

# Remove all conflicting Docker packages
for pkg in docker.io docker-doc docker-compose docker-compose-v2 podman-docker containerd runc; do 
    sudo apt-get remove $pkg
done

Note: If apt-get reports that none of these packages are installed, that’s perfectly normal and expected on fresh Ubuntu installations.

Data Preservation

Images, containers, volumes, and networks stored in /var/lib/docker/ are not automatically removed when uninstalling Docker. If you want a completely clean installation, you can manually remove this directory, but be careful as this will delete all Docker data permanently.

Step 2: Set Up Docker’s Official APT Repository

The recommended installation method is using Docker’s official APT repository, which ensures you get the latest stable version with security updates and bug fixes.

Add Docker’s GPG Key

First, update your package index and install required dependencies:

# Update package index
sudo apt-get update

# Install required packages for repository setup
sudo apt-get install ca-certificates curl

# Create directory for keyrings
sudo install -m 0755 -d /etc/apt/keyrings

# Download Docker's official GPG key
sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc

# Make the key readable
sudo chmod a+r /etc/apt/keyrings/docker.asc

Add Docker Repository to APT Sources

Add the Docker repository to your system’s software repository list:

# Add Docker repository to APT sources
echo \
  "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu \
  $(. /etc/os-release && echo "${UBUNTU_CODENAME:-$VERSION_CODENAME}") stable" | \
  sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

# Update package index with new repository
sudo apt-get update

This command automatically detects your Ubuntu version and architecture, ensuring the correct packages are downloaded.

Step 3: Install Docker Engine and Components

Now install Docker Engine along with all necessary components for a complete Docker setup:

# Install Docker Engine and related components
sudo apt-get install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

Installed Components Explained

• docker-ce: Docker Community Edition engine
• docker-ce-cli: Command-line interface for Docker
• containerd.io: Container runtime used by Docker
• docker-buildx-plugin: Extended build capabilities with BuildKit
• docker-compose-plugin: Docker Compose V2 plugin

Verify Installation

Confirm Docker is installed correctly by checking the version:

# Check Docker version
sudo docker --version

# Verify Docker Engine is running
sudo systemctl status docker

# Test Docker with hello-world container
sudo docker run hello-world

Step 4: Configure Docker User Permissions

By default, Docker commands require sudo privileges. To run Docker commands as a regular user, add your user to the docker group.

Create Docker Group and Add User

# Create docker group (may already exist)
sudo groupadd docker

# Add current user to docker group
sudo usermod -aG docker $USER

# Log out and log back in, or run:
newgrp docker

Test Non-Root Access

After logging out and back in, test Docker without sudo:

# Test Docker without sudo
docker run hello-world

# Check Docker info
docker info

Step 5: Configure Docker to Start on Boot

Enable Docker service to start automatically when the system boots:

# Enable Docker service
sudo systemctl enable docker.service
sudo systemctl enable containerd.service

# Start Docker service immediately
sudo systemctl start docker

Advanced Configuration and Optimization

Docker Daemon Configuration

Create a custom daemon configuration file for optimized performance:

# Create Docker daemon configuration directory
sudo mkdir -p /etc/docker

# Create daemon.json configuration file
sudo tee /etc/docker/daemon.json > /dev/null << 'EOF'
{
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "10m",
    "max-file": "3"
  },
  "storage-driver": "overlay2",
  "experimental": false
}
EOF

# Restart Docker to apply configuration
sudo systemctl restart docker

Configure Docker Hub Rate Limiting

To avoid Docker Hub rate limiting issues, consider configuring registry mirrors or authentication:

# Add registry mirrors to daemon.json
sudo tee /etc/docker/daemon.json > /dev/null << 'EOF'
{
  "registry-mirrors": [
    "https://mirror.gcr.io"
  ]
}
EOF

Security Best Practices

Docker Security Configuration

• Use non-root containers: Always run containers with non-privileged users when possible
• Limit container capabilities: Use --cap-drop and --cap-add flags appropriately
• Use trusted base images: Pull images only from official or verified publishers
• Regular updates: Keep Docker Engine and images updated with security patches
• Network isolation: Use custom Docker networks instead of default bridge network

Firewall Configuration for Docker

Configure UFW to work properly with Docker:

# Configure UFW for Docker
sudo ufw default deny incoming
sudo ufw default allow outgoing

# Allow SSH (adjust port as needed)
sudo ufw allow ssh

# Allow specific Docker services (example: web application on port 8080)
sudo ufw allow 8080/tcp

# Enable UFW
sudo ufw enable

Troubleshooting Common Issues

Issue 1: Permission Denied When Running Docker Commands

Problem: Getting "permission denied" error when running docker commands without sudo.

Solution: Ensure user is added to docker group and session is refreshed:

# Verify user is in docker group
groups $USER

# If not in docker group, add user
sudo usermod -aG docker $USER

# Refresh group membership without logging out
newgrp docker

Prevention: Always log out and log back in after adding user to docker group.

Issue 2: Docker Service Failed to Start

Problem: Docker daemon fails to start or crashes frequently.

Solution: Check system logs and storage space:

# Check Docker service status
sudo systemctl status docker

# View detailed logs
sudo journalctl -u docker.service

# Check disk space
df -h

# Restart Docker service
sudo systemctl restart docker

Prevention: Ensure adequate disk space and monitor system resources.

Issue 3: Port Already in Use Error

Problem: Container fails to start due to port conflicts.

Solution: Check port usage and adjust port mapping:

# Check which process is using a port
sudo lsof -i :8080

# Use different port mapping
docker run -p 8081:80 nginx

# Or stop conflicting service
sudo systemctl stop apache2

Issue 4: Storage Driver Issues

Problem: Docker fails to start due to storage driver problems.

Solution: Reset Docker data or change storage driver:

# Stop Docker
sudo systemctl stop docker

# Backup existing data (optional)
sudo cp -r /var/lib/docker /var/lib/docker.backup

# Change storage driver in daemon.json
sudo nano /etc/docker/daemon.json

# Restart Docker
sudo systemctl start docker

Issue 5: Network Connectivity Problems

Problem: Containers cannot access external networks or communicate with each other.

Solution: Check network configuration and DNS settings:

# List Docker networks
docker network ls

# Inspect default bridge network
docker network inspect bridge

# Test container connectivity
docker run --rm -it alpine ping google.com

# Create custom network if needed
docker network create mynetwork

Real-World Use Cases and Examples

Case Study 1: Web Development Environment

Setting up a complete web development stack with Docker:

# Create development network
docker network create dev-network

# Run MySQL database
docker run -d \
  --name mysql-dev \
  --network dev-network \
  -e MYSQL_ROOT_PASSWORD=devpassword \
  -e MYSQL_DATABASE=myapp \
  -v mysql-data:/var/lib/mysql \
  mysql:8.0

# Run PHP application with Apache
docker run -d \
  --name webapp \
  --network dev-network \
  -p 8080:80 \
  -v $(pwd)/src:/var/www/html \
  php:8.1-apache

# Run phpMyAdmin for database management
docker run -d \
  --name phpmyadmin \
  --network dev-network \
  -p 8081:80 \
  -e PMA_HOST=mysql-dev \
  phpmyadmin/phpmyadmin

Case Study 2: CI/CD Pipeline with Docker

Using Docker for continuous integration and deployment:

# docker-compose.yml for CI/CD
version: '3.8'
services:
  app:
    build: .
    ports:
      - "3000:3000"
    environment:
      - NODE_ENV=production
    volumes:
      - ./logs:/app/logs
    depends_on:
      - database
      - redis

  database:
    image: postgres:14
    environment:
      POSTGRES_DB: myapp
      POSTGRES_USER: appuser
      POSTGRES_PASSWORD: securepassword
    volumes:
      - postgres_data:/var/lib/postgresql/data

  redis:
    image: redis:6-alpine
    command: redis-server --appendonly yes
    volumes:
      - redis_data:/data

volumes:
  postgres_data:
  redis_data:

Case Study 3: Microservices Architecture

Deploying a microservices application with Docker Swarm:

# Initialize Docker Swarm
docker swarm init

# Deploy a stack of microservices
docker stack deploy -c docker-compose.prod.yml myapp

# Scale specific service
docker service scale myapp_web=3

# Monitor services
docker service ls
docker service ps myapp_web

Frequently Asked Questions (FAQ)

Q: Can I install Docker on Ubuntu derivatives like Linux Mint?

A: While not officially supported, Docker may work on Ubuntu derivatives. However, you might encounter compatibility issues. It's recommended to use the parent Ubuntu version's repository or consider using alternative installation methods like snap packages.

Q: How do I upgrade Docker to the latest version?

A: Update Docker using APT package manager:

sudo apt-get update
sudo apt-get upgrade docker-ce docker-ce-cli containerd.io

Q: What's the difference between Docker CE and Docker EE?

A: Docker CE (Community Edition) is free and open-source, suitable for developers and small teams. Docker EE (Enterprise Edition) includes additional enterprise features, support, and certification. For most Ubuntu users, Docker CE is sufficient.

Q: How much disk space does Docker typically use?

A: Docker's base installation is around 200MB, but images and containers can grow significantly. A typical development environment might use 5-20GB. Use docker system df to monitor usage and docker system prune to clean up unused resources.

Q: Can I run Docker containers without root access?

A: Yes, Docker supports rootless mode which allows running Docker daemon and containers as a non-root user. This provides better security isolation but has some limitations. Refer to Docker's rootless mode documentation for setup instructions.

Q: How do I configure Docker to use a proxy server?

A: Configure proxy settings in /etc/systemd/system/docker.service.d/http-proxy.conf:

[Service]
Environment="HTTP_PROXY=http://proxy.example.com:8080"
Environment="HTTPS_PROXY=http://proxy.example.com:8080"
Environment="NO_PROXY=localhost,127.0.0.1"

Q: What should I do if Docker Hub rate limits affect my builds?

A: Authenticate with Docker Hub to get higher rate limits, use alternative registries, implement registry mirrors, or cache frequently used images locally. Consider Docker Hub Pro subscription for unlimited public pulls.

Q: How do I backup and restore Docker containers and volumes?

A: Use docker commands to backup data:

# Backup volume
docker run --rm -v myvolume:/data -v $(pwd):/backup ubuntu tar czf /backup/myvolume.tar.gz -C /data .

# Restore volume
docker run --rm -v myvolume:/data -v $(pwd):/backup ubuntu tar xzf /backup/myvolume.tar.gz -C /data

Conclusion and Next Steps

This comprehensive installation guide ensures you have a robust, secure, and properly configured Docker environment on your Ubuntu system. Whether you're developing applications, setting up CI/CD pipelines, or deploying production workloads, this foundation will serve you well in your containerization journey.