phusion/passenger
Passenger
Passenger is a multitenant web server and dynamic process manager designed to host and manage web applications written in Ruby, Python, and Node.js. It functions as an application server that handles process and resource management, ensuring that multiple independent applications can run on a single server instance.
The project distinguishes itself through a flexible deployment model, capable of operating as a self-contained standalone web server or as an integration module for existing high-performance external web servers. It employs a language-agnostic interface to provide polyglot hosting and utilizes a multitenant architecture to optimize system resource usage.
Core capabilities include automated process management with dynamic scaling based on real-time traffic and a supervision system that automatically restarts crashed processes. The server also provides reverse-proxy load balancing to distribute requests to the least busy available process, alongside tools for health monitoring and log capture.
Server behavior and settings can be defined via a dedicated configuration file or command line arguments.
Features
- Application Multitenancy - Provides a multitenant architecture that runs multiple independent applications as separate operating system processes on one server.
- Application Servers - Functions as a multitenant application server that hosts multiple independent web applications on a single server instance.
- Application Process Lifecycles - Launches applications as external processes and automatically restarts them if they crash to ensure high availability.
- Plugin or Standalone Modes - Can operate as either a standalone web server or as a plugin module for an external server.
- Process Managers - Acts as a dynamic process manager that automatically scales application instances based on real-time traffic.
- Process Scaling - Provides dynamic scaling of application processes based on real-time traffic to optimize system resource usage.
- Supervised Process Restarts - Includes a supervision system that monitors application worker health and automatically restarts crashed processes.
- Multi-Language Application Servers - Supports multiple language runtimes including Ruby, Python, and Node.js within a single application server.
- Polyglot Application Interfaces - Implements a language-agnostic interface to host applications written in Ruby, Python, and Node.js on a single server.
- Process Supervision - Monitors application worker health and automatically restarts crashed processes to ensure high availability.
- Multi-Tenant Application Hosting - Hosts multiple independent web applications on a single server simultaneously using a multitenant architecture.
- Standalone Web Servers - Operates as a self-contained standalone web server to serve applications independently.
- Web Application Hosting - Handles incoming HTTP requests and manages the processes required to serve web applications in various languages.
- Polyglot Application Hosting - Provides language-agnostic hosting for web applications written in Ruby, Python, and Node.js.
- Web Server Hosting - Manages HTTP requests and application processes for multiple programming languages through various web server integrations.
- Multitenant - Employs a multitenant architecture to run multiple independent applications on a single server instance.
- Graceful Application Restarts - Allows refreshing the application process to apply code changes immediately without restarting the entire server.
- Server Configurations - Allows definition of server behavior, such as ports and addresses, via configuration files or command line arguments.
- Multi-Application Load Balancers - Distributes incoming HTTP requests to the least busy available application process to balance load across a multitenant server.
- Web Application Deployments - Automates the deployment and operation of web services to improve scalability and reliability across environments.
- Web Server Integrations - Functions as an integration module for existing high-performance web servers to manage application lifecycles.
- HTTP Reverse Proxies - Includes a reverse-proxy load balancer that distributes incoming HTTP requests to the least busy application process.
- Application Logging - Collects server-level events and application output into dedicated log files and the terminal for debugging.
- Application Health Monitors - Tracks the performance and stability of running application processes using administration and diagnosis tools.
- Standalone Server Modes - Can operate as a self-contained standalone web server independently of an external web server suite.
- Process Management - Process manager with direct Nginx integration.
