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Setting Up Docker on Ubuntu and Debian: Complete Guide

A comprehensive tutorial on installing and configuring Docker on Ubuntu and Debian systems, including best practices and troubleshooting.

Setting Up Docker on Ubuntu and Debian: Complete Guide

Setting Up Docker on Ubuntu and Debian: Complete Guide

Docker has revolutionized how we deploy and manage applications. This comprehensive guide will walk you through installing Docker on Ubuntu and Debian systems, from basic installation to advanced configuration.

Prerequisites

Before installing Docker, ensure your system meets these requirements:

  • Ubuntu 20.04 LTS or later, or Debian 10 or later
  • 64-bit processor
  • At least 4GB of RAM (8GB recommended)
  • Sudo privileges

Method 1: Installing from Official Docker Repository (Recommended)

Update System Packages

sudo apt update
sudo apt upgrade -y

Install Prerequisites

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

Add Docker's Official GPG Key

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

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

Add Docker Repository

# For Ubuntu
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

# For Debian
echo "deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/debian $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

Install Docker Engine

sudo apt update
sudo apt install -y docker-ce docker-ce-cli containerd.io docker-compose-plugin

Method 2: Using Convenience Script

Docker provides a convenience script for quick installation:

curl -fsSL https://get.docker.com -o get-docker.sh
sudo sh get-docker.sh

Note: Only use this method for development environments, not production.

Post-Installation Setup

Add User to Docker Group

To run Docker without sudo:

sudo usermod -aG docker $USER
newgrp docker

Enable Docker Service

sudo systemctl enable docker
sudo systemctl start docker

Verify Installation

docker --version
docker run hello-world

Docker Compose Installation

Docker Compose is now included as a plugin. Verify it's installed:

docker compose version

If not available, install manually:

sudo apt install docker-compose-plugin

Essential Docker Configuration

Configure Docker Daemon

Create or edit /etc/docker/daemon.json:

{
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "10m",
    "max-file": "3"
  },
  "storage-driver": "overlay2",
  "registry-mirrors": []
}

Set Resource Limits

For production environments, configure resource limits:

{
  "default-ulimits": {
    "nofile": {
      "Hard": 64000,
      "Name": "nofile",
      "Soft": 64000
    }
  }
}

Basic Docker Commands

Container Management

# Run a container
docker run -d --name nginx-server nginx

# List running containers
docker ps

# Stop a container
docker stop nginx-server

# Remove a container
docker rm nginx-server

# View container logs
docker logs nginx-server

Image Management

# Pull an image
docker pull ubuntu:22.04

# List images
docker images

# Remove an image
docker rmi ubuntu:22.04

# Build an image
docker build -t myapp .

Troubleshooting Common Issues

Permission Denied Error

If you get permission denied errors:

sudo chmod 666 /var/run/docker.sock

Docker Service Not Starting

Check service status and logs:

sudo systemctl status docker
sudo journalctl -u docker.service

Storage Issues

Clean up unused resources:

# Remove unused containers, networks, images
docker system prune -a

# Remove unused volumes
docker volume prune

Security Best Practices

1. Run Containers as Non-Root

FROM ubuntu:22.04
RUN groupadd -r appuser && useradd -r -g appuser appuser
USER appuser

2. Use Official Images

Always prefer official images from Docker Hub:

docker pull nginx:alpine
docker pull node:18-alpine

3. Scan Images for Vulnerabilities

docker scout quickview
docker scout cves ubuntu:22.04

4. Limit Container Resources

docker run -d --memory="512m" --cpus="0.5" nginx

Performance Optimization

Configure Storage Driver

For better performance on SSDs:

{
  "storage-driver": "overlay2",
  "storage-opts": [
    "overlay2.override_kernel_check=true"
  ]
}

Enable BuildKit

Add to your shell profile:

export DOCKER_BUILDKIT=1

Uninstalling Docker

If you need to remove Docker:

sudo apt purge docker-ce docker-ce-cli containerd.io docker-compose-plugin
sudo rm -rf /var/lib/docker
sudo rm -rf /var/lib/containerd

Next Steps

With Docker installed, you can:

  1. Create your first Dockerfile
  2. Set up Docker Compose for multi-container applications
  3. Explore container orchestration with Docker Swarm
  4. Learn about Docker networking and volumes
  5. Set up a container registry

Docker opens up endless possibilities for application deployment and development. Start with simple containers and gradually explore more advanced features as you become comfortable with the basics.

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