Docker and PHP: A Complete Guide to Application Containerization

Docker and PHP: Application Containerization from A to Z

Containerization of PHP applications using Docker has become the standard of modern web development. Whether you are creating a simple landing page or a complex enterprise application, Docker ensures environment consistency at all stages: from local development to production. In this article, we will break down all the stages of creating a Docker infrastructure for a PHP application — from a basic Dockerfile to a full stack with Nginx and MySQL.

Why Docker is Important for a PHP Developer

Traditional PHP development often faces the "it works on my machine" problem. Different PHP versions, extensions, server settings — all of this leads to conflicts. Docker solves this problem once and for all:

• Environment Isolation — each application has its own set of dependencies
• Reproducibility — the same environment on all machines
• Scalability — easily add new services (Redis, Elasticsearch)
• CI/CD Integration — containers are ideal for pipelines

Let's move from theory to practice and create a full Docker environment for a PHP application.

Creating a Basic Dockerfile for PHP

Let's start with the most important thing — the Dockerfile. This is the instruction for building the image of your PHP application. Here is the optimal configuration for a production-ready application:

# Use the official PHP image with FPMFROM php:8.2-fpm-alpine

# Install system dependenciesRUN apk add --no-cache \    git \    unzip \    libpq-dev \    libzip-dev \    && docker-php-ext-install \    pdo_mysql \    zip \    opcache

# Install ComposerCOPY --from=composer:latest /usr/bin/composer /usr/bin/composer

# Configure OPcache for productionRUN { \    echo 'opcache.memory_consumption=128'; \    echo 'opcache.interned_strings_buffer=8'; \    echo 'opcache.max_accelerated_files=4000'; \    echo 'opcache.revalidate_freq=2'; \    echo 'opcache.fast_shutdown=1'; \    echo 'opcache.enable_cli=1'; \} > /usr/local/etc/php/conf.d/opcache.ini

# Copy application filesWORKDIR /var/www/htmlCOPY . .

# Set permissionsRUN chown -R www-data:www-data /var/www/html \    && chmod -R 755 storage bootstrap/cache

# Run PHP-FPMCMD ["php-fpm"]

EXPOSE 9000

This Dockerfile uses Alpine Linux — a minimal image that significantly reduces the size of the final container. We install only the necessary extensions: pdo_mysql for working with the database and zip for Composer.

Building and Running the Container

# Build the imagedocker build -t my-php-app .

# Run the containerdocker run -d -p 9000:9000 --name php-app my-php-app

Full Stack with Nginx and MySQL via docker-compose

A real application rarely consists of a single PHP container. We need a web server and a database. This is where docker-compose comes to the rescue — a tool for orchestrating multiple containers.

Let's create a docker-compose.yml file:

version: '3.8'

services:  # PHP-FPM service  app:    build:      context: .      dockerfile: Dockerfile    container_name: php-app    volumes:      - ./:/var/www/html    networks:      - app-network

  # Nginx web server  nginx:    image: nginx:alpine    container_name: php-nginx    ports:      - "8080:80"    volumes:      - ./:/var/www/html      - ./docker/nginx/default.conf:/etc/nginx/conf.d/default.conf    depends_on:      - app    networks:      - app-network

  # MySQL database  db:    image: mysql:8.0    container_name: php-mysql    ports:      - "3306:3306"    environment:      MYSQL_ROOT_PASSWORD: root_password      MYSQL_DATABASE: app_database      MYSQL_USER: app_user      MYSQL_