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 GitOps based homelab. (see here)

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: (defined by ansible groups)
  • [nut_observer_fast_off]
  • [nut_observer]
  • [nut_critical]
• 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

1. Install nut, and run nut-scanner to fetch the UPS info. Example:

[nutdev1]
        driver = "usbhid-ups"
        port = "auto"
        vendorid = "0764"
        productid = "0601"
        product = "CP1500AVRLCD3"
        serial = "BHPPT7G00027"
        vendor = "CPS"
        bus = "003"

2. Fill in the details found there into the nut_setup role’s template files

3. Use the role nut_setup and point it at a server also in the [nut_critical] group. My Inventory has holmie in the [controller] group, and [nut_critical] group, so it is the ideal choice.

Done! Now that server should stay on till the very end, and only shutdown when the UPS sends a critical message.

NUT clients

Similar to the server, see the roles:

• nut_critical
• nut_observer
• nut_observer_fast_off

These do what you would expect:

• nut_critical wait for the critical message (actions = fsd) from the nut server
• nut_observer shuts down with 75% battery left.
• nut_observer_fast_off shuts down at 90% battery left.