Top notch! One thing I ran into on my system, 2 Truenas-12.0-U1 servers in master/slave, is that I needed to ensure the "Power Off UPS" setting was not turned on for my config. Otherwise part way through the boot process after the shutdown it would kill the UPS power and the kill the power to my Server mid boot.
This was the single best guide for setting up my two Truenas 12.0 U1.1 servers on a single UPS. Thank You !!! Minor detail: the UPS name set on the slave system needs to be the UPS name on the master system.
Thank you! This helped me set up my UPS. My specific UPS wasn't listed in the dropdown (Cyber Power PR1500LCDRT2U), but selecting a different model with the "usbhid-ups" driver did the trick. Next step - configuring the 2nd UPS I have. My server has redundant power supplies, which I have plugged into separate UPSs. (Which are plugged into separate power circuits.) Looks like I may need to manually edit some config files to get that working.