My homelab is constantly evolving. The latest will be on my homelab git repo

Currently I am using a docker-based homelab. The plan is to switch to a Kubernetes and GitOps based homelab.

This site will serve as a place for specific projects and things that need a few more words than the ones in a config file.

Network UPS Tools (NUT)

Battery backup for all the network and homelab things. (Bonus for my desktop too!)

I will be consolidating Jeff Geerling’s blog post on this into my configs, and my exact steps.

Layout and my devices:

  • Shutdown order:
    • Desktops
    • Holmie server
    • Kubernetes cluster
    • iMessage mac
    • pfsense
    • Raspberry Pi3
    • On dead battery: (no config)
      • Asus WAP
      • Network Switch
  • My UPS model: CP1500AVRLCD3-R (purchased 02/28/2025)
    • -R likely means refurbish
    • 3 is a later version made. it is this one
    • Using 2x of this battery: RB1290X2E

Step-by-step

NUT server setup pi3

  • Install: sudo apt install -y nut and plug UPS into pi3 then sudo nut-scanner
Scanning USB bus.
No start IP, skipping SNMP
Scanning XML/HTTP bus.
No start IP, skipping NUT bus (old connect method)
Scanning NUT bus (avahi method).
[nutdev1]
        driver = "usbhid-ups"
        port = "auto"
        vendorid = "0764"
        productid = "0601"
        product = "CP1500AVRLCD3"
        serial = "BHPPT7G00027"
        vendor = "CPS"
        bus = "001"
  • Append the above into sudo nano /etc/nut/ups.conf
[pi3]
        driver = "usbhid-ups"
        port = "auto"
        vendorid = "0764"
        productid = "0601"
        product = "CP1500AVRLCD3"
        serial = "BHPPT7G00027"
        vendor = "CPS"
        bus = "001"
  • sudo nano /etc/nut/upsd.conf and append LISTEN 0.0.0.0 3493
  • sudo nano /etc/nut/upsd.users and make an admin and observer users: (I saved this in my password manager as “NUT UPS server”)
[admin]
    password = password
    actions = set
    actions = fsd
    instcmds = all

[observer]
    password = password
    upsmon secondary
  • sudo nano /etc/nut/upsmon.conf comment out the existing FINALDELAY line, and add:
# Make sure you use your actual admin password...
MONITOR pi3@localhost 1 admin password primary

# You might also want to configure FINALDELAY and set it to a period long enough
# for your servers to all shut down, prior to the primary node shutting down and
# triggering the UPS to switch off its load, e.g. for 3 minutes:
FINALDELAY 180
  • sudo nano /etc/nut/nut.conf edit mode from none to netserver
  • Restart NUT: sudo systemctl restart nut-server && sudo systemctl enable nut-server && sudo systemctl restart nut-monitor && sudo systemctl enable nut-monitor
  • Done! Testing time:
    • upsc pi3 should output a bunch of info
    • If you have home assistant you should be able to add it via the NUT integration.

Any client setup

  • I will be using holmie as the server I am setting this up on. The process should be identical for additional clients.
  • sudo apt install nut-client -y then upsc [email protected] to verify connection
  • sudo nano /etc/nut/upsmon.conf add MONITOR [email protected] 1 observer password slave
  • sudo nano /etc/nut/nut.conf and edit MODE from none to netclient > MODE=netclient
  • Now this server will monitor wait for a fsd command from the NUT-server.
  • This setup will shutdown everything right before the battery dies. If this is not desired, keep reading.
  • Only installing nut-client is required for this to work.
  • Make a script that will monitor and shutdown based on the selected factors:
#!/bin/bash

# check ups status and battery %
BATTERY_LEVEL=$(upsc [email protected] battery.charge)
UPS_STATUS=$(upsc [email protected] ups.status)
SHUTDOWN_PERCENT=50
DEVICE_TAG=house

if [ "$UPS_STATUS" != OL ]; then # if not online
	# Check if UPS is on battery and if battery charge is less than 90 and isnt charging
	if [ "$UPS_STATUS" != "OL CHRG" ]; then # if not charging
		if [ "$BATTERY_LEVEL" -lt "$SHUTDOWN_PERCENT" ]; then
			# if less than the number, ntfy then shutdown in 1 minute
			curl -H "Tags: $DEVICE_TAG,bangbang" -H "Priority: high" -H "X-Title:HOLMIE SHUTTING DOWN" -d "" https://ntfy.holmlab.org/UPSuWd9jG23WS ; /sbin/shutdown -h +1
		fi
	fi
	if [ "$UPS_STATUS" = "OL CHRG" ]; then
		curl -H "Tags: battery,arrow_up" -H "Priority: min" -H "X-Title: UPS charging (at "$BATTERY_LEVEL"%)" -d "" https://ntfy.holmlab.org/UPSuWd9jG23WS
	fi
fi

if [ "$UPS_STATUS" = RB ]; then # replace battery?
	# NTFY if replacement battery
	curl -H "Tags: battery" -H "Priority: min" -H "X-Title: Replace UPS battery" -d "" https://ntfy.holmlab.org/UPSuWd9jG23WS
fi
  • Then sudo chmod 700 /etc/nut/ups_shutdown.sh then sudo su > crontab -e then append: */5 * * * * /etc/nut/ups_shutdown.sh
  • You do not need to use this many notifications. If there is an outage, I will be receiving many notification with this setup.
  • Below is a trimmed down version with fewer notifications:
#!/bin/bash

# check ups status and battery %
BATTERY_LEVEL=$(upsc [email protected] battery.charge)
UPS_STATUS=$(upsc [email protected] ups.status)
SHUTDOWN_PERCENT=90
DEVICE_TAG=desktop_computer

if [ "$UPS_STATUS" != OL ]; then # if not online
	# Check if UPS is on battery and if battery charge is less than 90 and isnt charging
	if [ "$UPS_STATUS" != "OL CHRG" ]; then # if not charging
		if [ "$BATTERY_LEVEL" -lt "$SHUTDOWN_PERCENT" ]; then
			# if less than the number, ntfy then shutdown in 1 minute
			curl -H "Tags: $DEVICE_TAG,bangbang" -H "Priority: high" -H "X-Title: SHADYPC SHUTTING DOWN" -d "" https://ntfy.holmlab.org/UPSuWd9jG23WS ; /sbin/shutdown -h +1
		fi
	fi
fi