Warning Light is a lightweight daemon running on NEMS 1.4.1+. It is a different type of notification system exclusive to NEMS Linux.

NEMS Warning Light: Hardware

If the state of your monitored hosts should change, Warning Light triggers a visual response by way of a tower signal lamp via GPIO.

  1. OK: Solid green light
  2. WARNING: Solid orange light
  3. UNKNOWN: Flashing orange light
  4. CRITICAL: Short siren every 15 minutes, solid red light.

Warning Light uses nems-api to monitor the status of your NEMS Linux server.

Warning Light can be connected directly to a supported NEMS Linux server, or to a supplemental device running the NEMS Tools Distro with network access, even through the Internet.

System Requirements

Warning Light can be connected directly to a Raspberry Pi, Pine64 and ODROID-based NEMS Linux servers. If your NEMS server is a different platform, you can connect your Warning Light to a supported device (such as a Raspberry Pi Zero) and install the NEMS Tools Distro, which will connect to any NEMS server, regardless of platform.


Pre-Built Kits:

Hey, these prices aren't final. Just waiting to build the prototype and then I'll have a better idea.

GPIO version: $175 USD

Includes everything you need to connect a working NEMS Warning Light to a Raspberry Pi GPIO (not included), fully assembled, soldered, with a 40-pin GPIO cable to connect to your existing Raspberry Pi device.

OOTB Version: $275 USD

The full kit. No other hardware needed. Fully assembled, soldered, and self-contained. Powered by a built-in Raspberry Pi Zero W (not removable - is soldered into the circuit), with Ethernet connectivity.


Buy the parts and build one yourself. Keep in mind this is a “basic” version of Warning Light. The pre-built version is more sophisticated, but the DIY version will work if you're looking to do it on the cheap, or just for the fun of making it yourself. https://amzn.to/2PYFA9O

NEMS Warning Light: Webhook

Send notifications directly to your webhook. For example, have your NEMS Linux server post alerts directly to your company Discord channel.

To use NEMS Warning Light's webhook feature, simply add your webhook URL to NEMS SST.

Webhook functionality requires NEMS Linux 1.5+. NEMS only sends webhooks. It does not receive them.

Currently Supported Webhooks:

  • Discord
  • Slack
  • Microsoft Office 365 / Teams

If you would like support added for another webhook, please simply put it in as a feature request in the Community Forum.

Configuring Webhooks

Microsoft Office 365 / Teams

NEMS Warning Light: Log Files

You can monitor what is happening with Warning Light by tailing the log file.

tail -f /var/log/nems/nems-tools/warninglight

You can view the current state of NEMS Warning Light:

cat /var/log/nems/nems-tools/currentstate
  • features/nems-tools/warninglight.txt
  • Last modified: 2019/03/14 11:18
  • by Robbie Ferguson