Kevin McConnell - Introducing Kamal Proxy - Rails World 2024

Kamal Proxy is a new proxy layer built to improve Rails app deployment, replacing Traffic in Kamal 1.0

Key features include:

• Gapless deployments with zero downtime between version updates
• Built-in HTTP/2 support and request/response buffering
• Automatic SSL certificate handling
• Host-based routing for multiple apps on same server
• X-Sendfile support for faster file serving
• Built-in HTTP caching via Thruster

Rollout functionality allows:

• Deploying alternate versions alongside main app
• Controlled traffic splitting based on accounts/percentages
• Canary deployments and A/B testing
• Easy rollback with rollout stop command

Performance improvements:

• Static file caching and serving via Thruster
• Request pausing for maintenance without dropping connections
• Response buffering to protect against slow clients
• More efficient asset serving than default Rails

Management features:

• Maintenance mode with custom pages
• Health checking
• Simple commands for deployment orchestration
• Multiple app support with automatic routing

Designed for self-hosting with minimal configuration while providing platform-like features normally found in managed services

Future roadmap includes:

• Load balancing improvements
• WebSocket acceleration
• Additional performance optimizations