Connect old Server using macOS 10.13 to UPS as slave of other devices using NUT

[michelangelo]

Hello. Having more than one device powered by my UPS, I seek the manner in which an old iMac running my home automation software and used as server will have a safe shutdown after having received the UPS information and instructions from a Network UPS Tool (NUT) Server. My NUT server could be a raspberry Pi correctly configured, or simply my pfSense router, as pfSense is out of the box NUT-compatible (and demands a safe shutdown).

On the mac app store, I can find the client that I need, but this client is only compatible with MacOS 10.15 Catalina. My server uses an old iMac only capable of 10.13 High Sierra.Otherwise, I have found very old UPS installations of NUT (like macOSX 10.4) too old for my mac.

Are there other alternatives, like configuring the mac as a master (rather than a slave) or using a USB Switch to feed both devices with the information feed.

Thank you for any pointers (including pointers to a specialised forum if needed).
(UPS: Eaton 3S; firewall: pfSense on freeBSD; Server iMasc 2011 running on macOS 10?13)

 

[Lifeisabeach]

Does the built-in feature to shut down when on a UPS that's engaged not do the job you need it to?

Set when your Mac shuts down while using a UPS

If your Mac desktop computer uses an uninterruptible power supply (UPS), you may be able to set how long the Mac runs on the UPS before shutting down.

support.apple.com

In some very brief browsing, I found a site where you can compile a NUT yourself from source.

Network UPS Tools - Download information

Power Devices support

networkupstools.org

 

[michelangelo]

Thanks. Indeed, the built-in features to softly shut down the mac when on UPS do the job. But then I need to connect by USB the UPS to the mac. Given that I also want to **** down soft my pfSense router and that I do not have another UPS, I need to receive the UPS info from somewhere. NUT permits to use the info received by the pfSense router (then used as server or master) to inform the mac (then used as client or slave). The pfSense router can be used as a NUT server, I try to use the mac as a NUT client.

-- or maybe use a USB hub to share the USB signal from the UPS, but I doubt that --

Yes, the NUT site is reputedly extremely well documented, for linux experts, which I am not.

Why OS 10.13 ? Because the server mac is my old iMac, born in 2011.