# Supervisord — Process Control System for Unix

> A client/server system for controlling processes on Unix-like operating systems. Supervisord starts, stops, and monitors long-running processes and automatically restarts them on failure.

## Install

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# Supervisord — Process Control System for Unix

## Quick Use
```bash
pip install supervisor
echo_supervisord_conf > /etc/supervisord.conf
# Add a program section, then:
supervisord -c /etc/supervisord.conf
supervisorctl status
```

## Introduction
Supervisor is a process control system for Unix that lets you manage and monitor long-running processes. It automatically starts processes at boot, restarts them on crash, and provides a CLI and web interface for managing process groups. It is widely used to run application servers, workers, and background tasks in production.

## What Supervisord Does
- Starts, stops, and restarts managed processes with automatic crash recovery
- Groups related processes for batch control (start/stop a service stack at once)
- Provides a CLI tool (`supervisorctl`) for interactive process management
- Exposes a web UI and XML-RPC API for remote monitoring
- Logs stdout and stderr from managed processes to rotated log files

## Architecture Overview
Supervisord runs as a daemon (the server process) that reads an INI-style configuration file defining programs and their parameters. Each managed program runs as a child process. The daemon monitors child processes via SIGCHLD signals and restarts them according to the configured policy. The `supervisorctl` client communicates with the daemon over a Unix socket or TCP using XML-RPC.

## Self-Hosting & Configuration
- Install via pip: `pip install supervisor`
- Generate a config template: `echo_supervisord_conf > /etc/supervisord.conf`
- Define programs in `[program:name]` sections with `command`, `directory`, and `user`
- Set `autorestart=true` for automatic crash recovery
- Enable the web UI by configuring `[inet_http_server]` with a port and credentials

## Key Features
- Automatic process restart on crash or exit
- Process groups for managing related services together
- Built-in log rotation for stdout and stderr
- Event listeners for custom notifications on process state changes
- Web dashboard for real-time status monitoring

## Comparison with Similar Tools
- **systemd** — Linux-native init system; Supervisord is cross-platform and simpler to configure
- **PM2** — Node.js-focused process manager with clustering; Supervisord is language-agnostic
- **Docker** — Container-level process management; Supervisord manages processes within a single host or container
- **runit** — Minimal init scheme; Supervisord offers richer monitoring and a web UI

## FAQ
**Q: Can Supervisord manage Docker containers?**
A: Supervisord manages Unix processes, not containers. It is often used inside Docker containers to run multiple processes in a single container when needed.

**Q: How does Supervisord handle process dependencies?**
A: Use `priority` values to control start order and `process_groups` to manage related services. For strict dependency ordering, use event listeners or startup scripts.

**Q: Does Supervisord work on macOS?**
A: Yes. Supervisord runs on any Unix-like system including macOS and Linux. It does not support Windows natively.

**Q: Can I extend Supervisord with plugins?**
A: Yes. Supervisord supports event listeners that react to process state changes, and third-party plugins like `superlance` add advanced monitoring features.

## Sources
- [GitHub Repository](https://github.com/Supervisor/supervisor)
- [Official Documentation](http://supervisord.org)

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Author: AI Open Source