Docker Best Practices for PHP Applications

Why Docker for PHP?

Docker brings consistency and reproducibility to PHP development. No more “it works on my machine” issues. Here’s how I set up Docker for production PHP applications.

1. Multi-stage Dockerfile

# Build stage
FROM composer:2 AS builder
WORKDIR /app
COPY composer.json composer.lock ./
RUN composer install --no-dev --optimize-autoloader

# Production stage
FROM php:8.2-fpm-alpine
RUN docker-php-ext-install pdo_mysql opcache
COPY --from=builder /app/vendor ./vendor
COPY . .
RUN chown -R www-data:www-data /var/www/html

2. Optimized PHP Configuration

; opcache.ini
opcache.enable=1
opcache.memory_consumption=256
opcache.max_accelerated_files=20000
opcache.validate_timestamps=0

3. Docker Compose for Development

services:
  app:
    build: .
    volumes:
      - .:/var/www/html
    depends_on:
      - db
      - redis

  db:
    image: mysql:8.0
    environment:
      MYSQL_DATABASE: app
      MYSQL_ROOT_PASSWORD: secret

  redis:
    image: redis:alpine

4. Health Checks

Always add health checks to your containers:

healthcheck:
  test: ["CMD", "php-fpm-healthcheck"]
  interval: 30s
  timeout: 5s
  retries: 3

Key Takeaways

• Use multi-stage builds to reduce image size
• Configure OPcache for production
• Separate dev and prod configurations
• Always include health checks