ServerMonitor

Multiple scripts that monitor a home server and log state changes to a local SQLite database on a USB flash drive, with a small web dashboard for viewing status, history, and events.

Written to run on an old repurposed router with minimal dependencies.

How it works

Two independent components, both writing to the same SQLite database:

• monitor.sh — runs every minute via cron. Performs two checks:

  • L3 (ICMP): ping to verify the host is reachable on the network
  • L7 (TCP): nc port check to verify the service is actually responding

  A /tmp state file tracks whether the server was previously seen as down, so a transition is logged once when it goes offline and once when it comes back — not on every poll.

• proxmox_monitor — a long-running daemon (started at boot via procd) that polls the Proxmox API every poll_interval seconds and detects:

  • Silent reboots — uptime decreasing between polls
  • High temperature — CPU temp crossing temp_threshold

Every poll from both components is logged to a readings table (for the dashboard's history chart); state transitions and detected problems are logged to an events table (for the dashboard's event log).

A CGI script (monitor-data) serves that data as JSON, and a static dashboard page (index.html) renders it — both served by the router's existing uhttpd, no extra web server needed.

Requirements

• OpenWRT router with a free USB port
• USB flash drive (used for the SQLite database — keeps write cycles off the router's internal flash)
• Packages: sqlite3-cli, block-mount, kmod-usb-storage, kmod-fs-ext4

Installation

This ships as a proper OpenWrt package (not a custom firmware image) — build it against the OpenWrt SDK, install the resulting .ipk with opkg, no reflashing required.

1. Drop this repo into an OpenWrt SDK's package/ directory and build:

   cp -r home-server-monitor <sdk>/package/home-server-monitor
   cd <sdk>
   make package/home-server-monitor/compile V=s

   This produces bin/packages/<arch>/base/home-server-monitor_1.0-1_<arch>.ipk. Dependencies (sqlite3-cli, block-mount, kmod-usb-storage, kmod-fs-ext4) are declared in the package and pulled in automatically.

2. Copy the .ipk to the router and install it:

   scp bin/packages/*/base/home-server-monitor_*.ipk root@<router-ip>:/tmp/
   ssh root@<router-ip> opkg install /tmp/home-server-monitor_*.ipk

   Installing the package automatically adds the cron entry for monitor.sh and enables the proxmox-monitor service — no manual file copying or service setup needed.

3. Format and mount the USB drive (first time only):

   block info                      # find the device, e.g. /dev/sda1
   mkfs.ext4 -L monitor /dev/sda1  # WARNING: erases the drive
   
   mkdir -p /mnt/usb
   block detect >> /etc/config/fstab
   uci set fstab.@mount[-1].target='/mnt/usb'
   uci set fstab.@mount[-1].enabled='1'
   uci commit fstab
   block mount

4. Edit /etc/config/monitor with your settings:

   config settings 'settings'
       option enabled            '1'
       option target_ip          '192.168.1.50'
       option target_port        '8006'
   
       option proxmox_node       'pve'
       option api_token_id       'root@pam!monitor'
       option api_token_secret   'your-api-token-secret'
       option temp_threshold     '80'
       option poll_interval      '60'
   
       option db_path            '/mnt/usb/monitor/monitor.db'
   

5. If the USB drive wasn't mounted yet at install time, initialize the database manually (the package's postinst will remind you if so):

   sqlite3 /mnt/usb/monitor/monitor.db < /usr/share/home-server-monitor/schema.sql

6. Restart the daemon and cron to pick up your config:

   /etc/init.d/proxmox-monitor restart
   /etc/init.d/cron restart

7. Open the dashboard at http://<router-ip>/monitor/.

See docs/setup.md for the full step-by-step, including SSH access and the SDK setup.

Configuration

Option	Description
enabled	Set to 1 to activate monitoring
target_ip	IP address of the server to monitor
target_port	TCP port for L7 service check (optional)
proxmox_node	Node name as configured in Proxmox (default pve)
api_token_id	Proxmox API token ID, e.g. root@pam!monitor
api_token_secret	Proxmox API token secret
temp_threshold	CPU temperature (°C) that triggers a temp_high event
poll_interval	Seconds between Proxmox API polls
db_path	Path to the SQLite database (on the USB drive)

Maintenance

The database grows indefinitely by default. Add a weekly cron entry to prune old readings so the flash drive doesn't fill up:

sqlite3 /mnt/usb/monitor/monitor.db \
  "DELETE FROM readings WHERE ts < strftime('%s','now','-90 days');"