In-depth

General Passenger

• Lightweight Ruby dependency
• Integration modes (Nginx, Apache, Standalone)
• Passenger open source vs Passenger Enterprise
• Hooking in to Passenger

General concepts

• About processes
• About environment variables
• Accurately measuring memory usage

Behavior, architecture & internals

• How Passenger autodetects applications
• Request load balancing
• How dynamic scaling of application processes works
• Instance registry
• Security update check
• Anonymous telemetry reporting
• Data reporting mechanism

Passenger's exposed application environment

• Stdin, stdout and stderr channels
• Apache per-request environment variables

Node.js-specific

• Reverse port binding
• Secure HTTP headers