Introduction: Why Docker?

Have you ever said “but it works on my machine” only to discover your application crashes when deployed elsewhere? Docker solves this problem by packaging your application and all its dependencies into a standardized unit called a container. Think of containers as lightweight, portable, self-sufficient boxes that can run anywhere Docker is installed.

What You’ll Learn

In this guide, you’ll discover how to:

Set up Docker on your system
Understand Docker fundamentals
Launch your first containers
Host websites, databases, and more
Connect services together
Create development environments
Save time with pre-built solutions

Let’s dive in!

Getting Started with Docker

Installation

First things first: you need Docker on your system.

For Windows/Mac:

Download Docker Desktop from docker.com
Run the installer and follow the prompts
Start Docker Desktop

For Linux:

# Update package info
sudo apt update

# Install prerequisites
sudo apt install apt-transport-https ca-certificates curl software-properties-common

# Add Docker's official GPG key
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

# Add the Docker repository
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"

# Update package database
sudo apt update

# Install Docker
sudo apt install docker-ce

# Start Docker
sudo systemctl start docker

# Enable Docker to start on boot
sudo systemctl enable docker

Verify your installation by running:

docker --version
docker run hello-world

Docker Basics

Let’s understand some key Docker terminology:

Image: A read-only template with instructions for creating a Docker container
Container: A runnable instance of an image
Dockerfile: A text file with commands to build an image
Docker Hub: A repository of Docker images (like GitHub for Docker)
Volume: A way to persist data generated by and used by Docker containers
Network: How containers communicate with each other

Your First Project: Hosting a Website

Let’s start with something simple: hosting a static website using Nginx.

Option 1: Using an Official Image

# Create a directory for your website
mkdir my-website
cd my-website

# Create a simple index.html file
echo "<html><body><h1>My Docker Website</h1><p>It works!</p></body></html>" > index.html

# Run an Nginx container, mapping your directory to the container's web root
docker run -d -p 8080:80 -v $(pwd):/usr/share/nginx/html --name my-website nginx

Visit http://localhost:8080 in your browser to see your website!

Option 2: Creating Your Own Image

Create a file named Dockerfile:

DockerfileCopyFROM nginx:latest
COPY . /usr/share/nginx/html

Build and run your custom image:

docker build -t my-website-image .
docker run -d -p 8080:80 --name my-website my-website-image

Hosting a Database

Next, let’s set up a MySQL database:

# Create a directory for database data
mkdir mysql-data

# Run a MySQL container
docker run -d \
  --name my-mysql \
  -p 3306:3306 \
  -v $(pwd)/mysql-data:/var/lib/mysql \
  -e MYSQL_ROOT_PASSWORD=mysecretpassword \
  -e MYSQL_DATABASE=mydatabase \
  mysql:8.0

You now have a MySQL database running on port 3306!

Setting Up phpMyAdmin for Database Management

Let’s add phpMyAdmin to manage your MySQL database:

docker run -d \
  --name phpmyadmin \
  -p 8081:80 \
  -e PMA_HOST=my-mysql \
  --link my-mysql:db \
  phpmyadmin/phpmyadmin

Access phpMyAdmin at http://localhost:8081 and log in with username root and password mysecretpassword.

Create a Full Web Stack: WordPress Example

Want to run WordPress? It’s simple with Docker:

# Create a network for WordPress and MySQL to communicate
docker network create wordpress-network

# Run MySQL for WordPress
docker run -d \
  --name wordpress-db \
  --network wordpress-network \
  -v wordpress-mysql-data:/var/lib/mysql \
  -e MYSQL_ROOT_PASSWORD=mysecretpassword \
  -e MYSQL_DATABASE=wordpress \
  -e MYSQL_USER=wordpress \
  -e MYSQL_PASSWORD=wordpress \
  mysql:5.7

# Run WordPress
docker run -d \
  --name wordpress \
  --network wordpress-network \
  -p 8080:80 \
  -e WORDPRESS_DB_HOST=wordpress-db \
  -e WORDPRESS_DB_USER=wordpress \
  -e WORDPRESS_DB_PASSWORD=wordpress \
  -e WORDPRESS_DB_NAME=wordpress \
  wordpress

Visit http://localhost:8080 to set up your WordPress site!

Remote Desktop in Docker

Need a GUI environment? You can run a Remote Desktop inside Docker:

docker run -d \
  --name remote-desktop \
  -p 3389:3389 \
  -e USER=myuser \
  -e PASSWORD=mypassword \
  --shm-size 1g \
  rattydave/docker-ubuntu-xrdp-mate-custom:latest

Connect to your remote desktop using any RDP client (like Microsoft Remote Desktop) at localhost:3389.

Development Environments

VS Code Remote Development

The VS Code Remote Development extension allows you to use a container as a development environment:

Install VS Code and the “Remote – Containers” extension
Create a .devcontainer folder in your project
Add a devcontainer.json file:

jsonCopy{
  "name": "Node.js Development",
  "image": "node:14",
  "extensions": [
    "dbaeumer.vscode-eslint"
  ],
  "forwardPorts": [3000],
  "postCreateCommand": "npm install"
}

Open the project in VS Code and click “Reopen in Container”

Docker Compose: Managing Multiple Containers

Docker Compose lets you define and run multi-container applications:

Create a docker-compose.yml file:

yamlCopyversion: '3'

services:
  web:
    image: nginx:latest
    ports:
      - "8080:80"
    volumes:
      - ./website:/usr/share/nginx/html
    depends_on:
      - db
  
  db:
    image: mysql:8.0
    volumes:
      - mysql-data:/var/lib/mysql
    environment:
      MYSQL_ROOT_PASSWORD: mysecretpassword
      MYSQL_DATABASE: mydatabase
  
  phpmyadmin:
    image: phpmyadmin/phpmyadmin
    ports:
      - "8081:80"
    environment:
      PMA_HOST: db
    depends_on:
      - db

volumes:
  mysql-data:

Run your multi-container setup with:

docker-compose up -d

Stop everything with:

docker-compose down

Time-Saving Docker Containers

Here are some ready-to-use containers for popular applications:

Portainer – Docker Management UI

docker run -d \
  -p 9000:9000 \
  --name portainer \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -v portainer_data:/data \
  portainer/portainer-ce

Access at http://localhost:9000

Nextcloud – Your Personal Cloud

docker run -d \
  --name nextcloud \
  -p 8082:80 \
  -v nextcloud:/var/www/html \
  nextcloud

Access at http://localhost:8082

Grafana – Analytics & Monitoring

docker run -d \
  --name=grafana \
  -p 3000:3000 \
  grafana/grafana

Access at http://localhost:3000 (default login: admin/admin)

Jenkins – CI/CD Pipeline

docker run -d \
  --name jenkins \
  -p 8083:8080 \
  -p 50000:50000 \
  -v jenkins_home:/var/jenkins_home \
  jenkins/jenkins:lts

Access at http://localhost:8083

Best Practices

Use Official Images: Always start with official images from Docker Hub when possible
Keep Images Small: Use Alpine-based images when available
Don’t Run as Root: Use the USER instruction in your Dockerfile
Use .dockerignore: Exclude unnecessary files
Use Volumes for Persistence: Don’t store data in containers
One Process Per Container: Follow the single responsibility principle
Use Environment Variables: For configuration
Tag Your Images: Don’t rely on the latest tag

Troubleshooting

Container won’t start: docker logs container-name
See running containers: docker ps
See all containers (including stopped): docker ps -a
Remove all stopped containers: docker container prune
Remove unused images: docker image prune

Next Steps

Learn more about Docker networking
Explore Docker Swarm for container orchestration
Look into Kubernetes for production deployments
Create your own Docker images
Implement CI/CD pipelines with Docker

Conclusion

Congratulations! You’ve taken your first steps into the world of Docker. You now have the knowledge to containerize your applications, create development environments, and deploy services with ease. Keep experimenting and soon you’ll be creating your own sophisticated Docker-based solutions.

Remember: Docker isn’t just a tool; it’s a new way of thinking about software development and deployment. Embrace the containerization mindset, and you’ll find yourself building more portable, scala

Happy coding!

Docker For Dummies: Kickstart Your Journey to Pro-Level Projects