Docker Dev vs Prod — Volume Mounts, Multi-Container Setup

How to structure Docker for local development vs production with Django + Next.js. The key insight: dev mounts your code as a volume; prod bakes code into the image.

Why / When to Use

When you have a Django backend + Next.js frontend and want hot-reload during development, while keeping prod containers clean and self-contained.

Core Concept / Commands

Dev docker-compose (laptop)

# docker-compose.dev.yml
services:
  db:
    image: postgres:15
    environment:
      POSTGRES_DB: myapp
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: devpassword
    ports:
      - "5432:5432"
    volumes:
      - pgdata_dev:/var/lib/postgresql/data
 
  backend:
    build:
      context: ./backend
      dockerfile: Dockerfile.dev
    volumes:
      - ./backend:/app        # ← your local code mounted into container
    environment:
      DATABASE_URL: postgres://postgres:devpassword@db/myapp
      SECRET_KEY: dev-secret-key
      DEBUG: "True"
    ports:
      - "8000:8000"
    depends_on:
      db:
        condition: service_healthy
    command: python manage.py runserver 0.0.0.0:8000
 
  frontend:
    build:
      context: ./frontend
      dockerfile: Dockerfile.dev
    volumes:
      - ./frontend:/app       # ← your local code mounted into container
      - /app/node_modules     # keep node_modules inside container
    environment:
      NEXT_PUBLIC_API_URL: http://localhost:8000
      WATCHPACK_POLLING: "true"   # needed for hot reload inside docker
    ports:
      - "3000:3000"
    command: npm run dev
 
volumes:
  pgdata_dev:

Dev Dockerfiles (no COPY . . — code comes via volume)

# backend/Dockerfile.dev
FROM python:3.12-slim
WORKDIR /app
COPY requirements.txt .
RUN pip install -r requirements.txt
# No COPY . . — code is mounted
EXPOSE 8000
CMD ["python", "manage.py", "runserver", "0.0.0.0:8000"]

# frontend/Dockerfile.dev
FROM node:20-alpine
WORKDIR /app
COPY package*.json .
RUN npm install
# No COPY . . — code is mounted
EXPOSE 3000
CMD ["npm", "run", "dev"]

Prod Dockerfiles (code baked in)

# backend/Dockerfile
FROM python:3.12-slim
WORKDIR /app
COPY requirements.txt .
RUN pip install -r requirements.txt
COPY . .                     # ← code baked into image
RUN python manage.py collectstatic --noinput
EXPOSE 8000
CMD ["gunicorn", "myapp.wsgi:application", "--bind", "0.0.0.0:8000"]

# frontend/Dockerfile  (multi-stage build)
FROM node:20-alpine AS builder
WORKDIR /app
COPY package*.json .
RUN npm ci
COPY . .
RUN npm run build            # ← build baked into image
 
FROM node:20-alpine
WORKDIR /app
COPY --from=builder /app/.next ./.next
COPY --from=builder /app/public ./public
COPY --from=builder /app/package*.json ./
RUN npm ci --production
EXPOSE 3000
CMD ["npm", "start"]

Start dev environment

docker compose -f docker-compose.dev.yml up

Run Django commands in dev

docker compose -f docker-compose.dev.yml exec backend python manage.py makemigrations
docker compose -f docker-compose.dev.yml exec backend python manage.py migrate
docker compose -f docker-compose.dev.yml exec backend python manage.py createsuperuser
docker compose -f docker-compose.dev.yml exec backend python manage.py shell

Makefile shortcuts

dev:
	docker compose -f docker-compose.dev.yml up
 
down:
	docker compose -f docker-compose.dev.yml down
 
migrate:
	docker compose -f docker-compose.dev.yml exec backend python manage.py migrate
 
makemigrations:
	docker compose -f docker-compose.dev.yml exec backend python manage.py makemigrations
 
shell-backend:
	docker compose -f docker-compose.dev.yml exec backend python manage.py shell
 
logs:
	docker compose -f docker-compose.dev.yml logs -f

Key Options / Variants

Zero-downtime prod deploy (blue-green)

Run two named backend instances (backend_blue, backend_green). Deploy new code to the inactive one, wait for healthcheck, reload nginx to switch traffic, then stop the old one.

# nginx.conf switch (no reload downtime)
sed -i "s/backend_$OLD/backend_$NEW/g" nginx.conf
docker compose exec nginx nginx -s reload

Rolling update (Docker Swarm / Compose v2)

# docker-compose.yml — prod
backend:
  deploy:
    replicas: 2
    update_config:
      parallelism: 1
      delay: 10s
      order: start-first     # start new before stopping old

Gotchas

• WATCHPACK_POLLING: "true" is required for Next.js hot reload inside Docker on some systems
• Never use docker compose down -v in prod — it destroys the pgdata volume and all data
• --no-deps in docker compose up restarts only that container, leaving db untouched
• node_modules must be excluded from the volume mount with /app/node_modules to avoid host/container conflicts
• Claude Code on your laptop can manage all Docker commands (build, exec, logs) from the host — it doesn’t need to be inside the container

Source

Conversation: “CI/CD setup for Django and Next.js” — 2026-05-13