Deployer — Zero-Downtime PHP Deployment Tool

Introduction

Deployer automates PHP application deployments over SSH with atomic symlink releases. It eliminates downtime by preparing new releases in a separate directory and switching a symlink only after all tasks succeed.

What Deployer Does

• Executes zero-downtime deployments via atomic symlink switching
• Provides built-in recipes for Laravel, Symfony, WordPress, and more
• Manages multiple servers and deployment stages
• Supports parallel deployment to multiple hosts simultaneously
• Rolls back to previous releases on failure automatically

Architecture Overview

Deployer connects to remote servers via SSH (using phpseclib or native SSH). Each deployment creates a new release directory, runs build tasks (composer install, asset compilation), and atomically switches the current symlink. A configurable number of past releases are kept for rollback. Recipes are PHP files defining tasks, and custom tasks can hook into any stage of the pipeline.

Self-Hosting & Configuration

• Install globally with composer global require deployer/deployer or per-project
• Initialize config with dep init which generates deploy.php
• Define hosts with SSH credentials or agent forwarding
• Set shared files and directories that persist across releases
• Configure the number of releases to keep with set('keep_releases', 5)

Key Features

• Atomic deployments with instant symlink switching
• Built-in recipes for 20+ PHP frameworks and CMSes
• Parallel execution across multiple servers
• Automatic rollback on task failure
• Provisioning support for setting up fresh servers

Comparison with Similar Tools

• Capistrano — Ruby-based deployer; Deployer offers the same model in PHP
• Envoyer — Laravel-hosted deployment SaaS; Deployer is open source and self-managed
• Kamal — Docker-based deployment; Deployer works with traditional PHP hosting without containers
• Ansible — general infrastructure automation; Deployer is specialized for PHP deployment workflows
• GitHub Actions — CI/CD platform; Deployer handles the deployment stage specifically with rollback support

FAQ

Q: Does Deployer require root access on the server? A: No. It works with a regular SSH user that has write access to the deployment directory.

Q: Can Deployer run database migrations during deployment? A: Yes. You can add migration commands as tasks in the deployment recipe.

Q: How does rollback work? A: Deployer keeps previous releases on disk and switches the current symlink back to the last working release with dep rollback.

Q: Does Deployer support Docker-based deployments? A: Deployer is designed for traditional server deployments but can run Docker commands as custom tasks.

Sources

• https://github.com/deployphp/deployer
• https://deployer.org/docs