Docker for Developers: Complete Setup, Dockerfile & Docker Compose Guide

Docker for Developers

Docker allows developers to package applications and their dependencies into containers so they can run consistently across different environments.

Docker Compose extends this workflow by allowing multiple services to be defined and managed together.

1. Install Docker

Docker Desktop is the easiest way to get Docker on Windows and macOS and includes Docker Engine, Docker CLI and Docker Compose.

After installation:

Check Compose:

2. Run Your First Container

Run Nginx:

Open:

3. Important Docker Concepts

Image

A read-only template used to create containers.

Container

A running instance of an image.

Dockerfile

Instructions used to build an image.

Volume

Persistent storage outside the container lifecycle.

Network

Allows containers to communicate.

Registry

A location for storing and distributing images.

4. Common Docker Commands

List running containers:

List all containers:

List images:

Stop a container:

Start:

Remove:

Remove image:

View logs:

Follow logs:

Open a shell:

5. Create a Dockerfile

Example Python application:

FROM python:3.12-alpine

WORKDIR /app

COPY requirements.txt .

RUN pip install -r requirements.txt

COPY . .

EXPOSE 5000

CMD ["python", "app.py"]

Build:

Run:

6. Environment Variables

Create:

Example:

DATABASE_URL=postgresql://localhost/mydb
API_KEY=your-key

Do not commit secrets.

Add .env to .gitignore.

7. Docker Compose

Create:

Example:

services:
  web:
    build: .
    ports:
      - "8000:5000"
    environment:
      REDIS_HOST: redis
      REDIS_PORT: 6379
    depends_on:
      redis:
        condition: service_healthy

  redis:
    image: redis:alpine
    healthcheck:
      test: ["CMD", "redis-cli", "ping"]
      interval: 5s
      timeout: 3s
      retries: 5

Start:

Background mode:

Stop:

Docker's current Compose documentation covers services, networks, volumes, health checks, logs, exec, configuration and Compose Watch.

8. Docker Compose Commands

docker compose up
docker compose up -d
docker compose down
docker compose ps
docker compose logs
docker compose logs -f
docker compose restart
docker compose build
docker compose pull
docker compose config
docker compose exec

Example:

9. Persistent Volumes

Without a volume, container data can disappear when containers are removed.

Example:

services:
  redis:
    image: redis:alpine
    volumes:
      - redis-data:/data

volumes:
  redis-data:

Start:

Remove containers and volumes:

Be careful: -v removes named volumes and their stored data.

10. Docker Debugging

Check containers:

View logs:

Enter container:

For Compose:

Enter service:

Check resolved Compose configuration:

11. Docker Development Workflow

1. Create Dockerfile
2. Build image
3. Run container
4. Inspect logs
5. Add environment variables
6. Add volumes
7. Add Docker Compose
8. Add health checks
9. Test locally
10. Build production image

Docker Cheat Sheet

docker build -t app .
docker run app
docker ps
docker ps -a
docker images
docker logs <container>
docker exec -it <container> sh
docker stop <container>
docker rm <container>
docker rmi <image>

docker compose up
docker compose up -d
docker compose down
docker compose ps
docker compose logs -f
docker compose exec <service> sh
docker compose build
docker compose config