Systant

A comprehensive Elixir-based system monitoring solution with real-time dashboard, designed for deployment across multiple NixOS hosts.

Components

• Server (server/): Elixir OTP application that collects and publishes system metrics via MQTT
• Dashboard (dashboard/): Phoenix LiveView web dashboard for real-time monitoring
• Nix Integration: Complete NixOS module and packaging for easy deployment

Features

System Metrics Collection

• CPU: Load averages (1/5/15min) and utilization monitoring
• Memory: System memory usage and swap monitoring
• Disk: Usage statistics and capacity monitoring for all drives
• System Alarms: Real-time alerts for disk space, memory pressure, etc.
• System Info: Uptime, Erlang/OTP versions, scheduler information

Real-time Dashboard

• Phoenix LiveView interface showing all connected hosts
• Live system metrics and alert monitoring
• Automatic reconnection and error handling

MQTT Integration

• Publishes comprehensive system metrics every 30 seconds
• Uses hostname-based topics: systant/${hostname}/stats
• Structured JSON payloads with full system data
• Configurable MQTT broker connection

Quick Start

Development Environment

# Enter Nix development shell
nix develop

# Run the server
cd server && mix run --no-halt

# Run the dashboard (separate terminal)
just dashboard
# or: cd dashboard && mix phx.server

Production Deployment (NixOS)

# Build and install via Nix
nix build
sudo nixos-rebuild switch --flake .

# Or use the NixOS module in your configuration:
# imports = [ ./path/to/systant/nix/nixos-module.nix ];
# services.systant.enable = true;

Configuration

Default MQTT configuration (customizable via environment variables):

• Host: mqtt.home:1883
• Topics: systant/${hostname}/stats and systant/${hostname}/commands
• Interval: 30 seconds
• Client ID: systant_${random} (auto-generated to avoid conflicts)

Architecture

• Server: server/lib/systant/mqtt_client.ex - MQTT publishing and command handling
• Metrics: server/lib/systant/system_metrics.ex - System data collection using :os_mon
• Dashboard: dashboard/lib/dashboard/mqtt_subscriber.ex - Real-time MQTT data consumption
• Nix: nix/package.nix and nix/nixos-module.nix - Complete packaging and deployment

Roadmap

• ✅ Phase 1: System metrics collection with real-time dashboard
• 🔄 Phase 2: Command system for remote host management
• 🔄 Phase 3: Home Assistant integration for automation

See CLAUDE.md for detailed development context and implementation notes.