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Otto
Otto

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Docker for Solo Developers: The Only Guide You Need in 2026

#docker #programming #devops #beginners

I used to deploy my apps with scp and manual config files. Then I discovered Docker and realized I'd been wasting hours every week.

Here's the practical Docker guide I wish I had when starting out.

Why Docker Changes Everything

Before Docker, deploying meant:

  • "Works on my machine" disasters
  • Manual dependency installation on every server
  • Environment differences between dev, staging, and production
  • Hours debugging "but it worked locally!"

With Docker, you ship a container — a box with your app AND everything it needs. Same box everywhere.

Docker in 5 Minutes

Installation 

# macOS / Windows: Install Docker Desktop
# Linux:
curl -fsSL https://get.docker.com | sh
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Your First Dockerfile 

# Start from an official base image
FROM node:20-alpine

# Set working directory
WORKDIR /app

# Copy dependency files first (for caching)
COPY package*.json ./

# Install dependencies
RUN npm ci --only=production

# Copy source code
COPY . .

# Expose port
EXPOSE 3000

# Start the app
CMD ["node", "server.js"]
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Build and run:

docker build -t my-app .
docker run -p 3000:3000 my-app
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That's it. Your app runs in a container.

The Commands You'll Use 90% of the Time 

# Build an image
docker build -t app-name .

# Run a container
docker run -p 8080:3000 app-name

# Run in background (detached)
docker run -d -p 8080:3000 app-name

# List running containers
docker ps

# Stop a container
docker stop container-id

# View logs
docker logs container-id -f

# Shell into a running container
docker exec -it container-id sh

# Clean up everything
docker system prune -a
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Docker Compose: Run Multiple Services

Most real apps need a database, cache, and the app itself. Docker Compose orchestrates all of them.

# docker-compose.yml
version: "3.9"

services:
  app:
    build: .
    ports:
      - "3000:3000"
    environment:
      - DATABASE_URL=postgres://user:pass@db:5432/mydb
    depends_on:
      - db
      - redis

  db:
    image: postgres:16
    environment:
      POSTGRES_USER: user
      POSTGRES_PASSWORD: pass
      POSTGRES_DB: mydb
    volumes:
      - postgres_data:/var/lib/postgresql/data

  redis:
    image: redis:7-alpine

volumes:
  postgres_data:
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Start everything:

docker compose up -d
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One command. App + database + cache, all running.

Real-World Tips for Solo Devs

1. Use .dockerignore 

node_modules
.git
.env
*.log
dist
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Keeps your images small and build times fast.

2. Multi-stage Builds (Smaller Images) 

# Stage 1: Build
FROM node:20 AS builder
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
RUN npm run build

# Stage 2: Production (much smaller)
FROM node:20-alpine
WORKDIR /app
COPY --from=builder /app/dist ./dist
COPY --from=builder /app/node_modules ./node_modules
CMD ["node", "dist/server.js"]
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Result: 1.2GB → 180MB image.

3. Never Store Secrets in Images 

# Wrong
ENV DATABASE_PASSWORD=supersecret

# Right: use environment variables at runtime
docker run -e DATABASE_PASSWORD=$DB_PASS my-app
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4. Health Checks 

HEALTHCHECK --interval=30s --timeout=10s --retries=3 \
  CMD curl -f http://localhost:3000/health || exit 1
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Docker restarts unhealthy containers automatically.

Free Deployment Options in 2026

With Docker, you can deploy anywhere for free or cheap:

  • Railway.app — push Dockerfile, it deploys (free tier available)
  • Render.com — Docker support, free tier
  • Fly.io — excellent free tier, global edge
  • GitHub Actions + VPS — $5/month VPS, full control

The Docker Mindset

Think of containers as immutable units:

  • Never SSH into a production container to make changes
  • Fix → rebuild → redeploy
  • Logs go to stdout/stderr, not files
  • State goes in volumes or external databases

Bottom Line

Docker takes a few days to click. Once it does, you'll never go back to manual deployments.

Start with a simple Dockerfile for your next project. Then add Docker Compose when you need a database. You'll wonder how you shipped apps without it.

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