I didn't know about the Kreaweb guide until now. I followed the Techno Tim video for set up in my Proxmox cluster and it worked with some differences listed below as I'm using an old APC UPS which communicates over serial instead of USB. I had a quick look of the Kreaweb guide, and I believe it doesn't differ too much from the Techno Tim one. No you don't need to setup an LXC container. As listed in the docs, "We use a seperate LXC container because, for security reasons, we don NOT want to install a webserver directly onto our Proxmox PVE." It is just for the Apache server for presenting the UPS statistics in a graphical user interface. I don't use the apache server anyway, I'm using a docker container called PeaNUT that can connect to the NUT server and present the stats in a webpage. To put it in other words (which the Kreaweb guide didn't explain in depth), nut-server is used to communicate with the UPS and allow nut-clients to connect to them to get the latest status nut-client is used to listen to nut-server and run timers/scripts depending on the status of the server (e.g. shutting down the computer) For the Proxmox server that is connected to the UPS, you need to install both nut-server and nut-client, nut-server for communicating with the UPS and sharing it out and nut-client for getting the UPS status on the command line or shutting down itself For the "clients", just install nut-client directly on them so that it can monitor the server and shut down themselves. If you want a web GUI for presenting the NUT status and stats, run a separate LXC container with nut-client and apache as mentioned in the Kreaweb guide, or run a separate WebNUT or PeaNUT docker container. My major differences with the guides: One - Run the NUT server as root As I'm using an APC UPS with serial connection, I have to run the NUT server as root as the serial device /dev/ttyS0 is owned by root. Otherwise, the NUT server can't use the serial port. Example ups.conf: user = root pollinterval = 1 maxretry = 3 [apc-sc420] driver = apcsmart port = /dev/ttyS0 cable = 940-0024C desc = "APC Smart UPS 420VA SC420I" Two - upssched In the TechnoTim guide, the upssched.conf has the configuration AT ONBATT * START-TIMER earlyshutdown 30. This means that the computer will shutdown 30 seconds after the UPS is on battery, which is definitely too short and I changed it to a longer value (e.g. 1800 for 30 minutes). Also, most people would want the shutdown timer to cancel when the UPS comes back on line power, therefore, I have to add a line AT ONLINE * CANCEL-TIMER earlyshutdown there. In the Kreaweb guide, the early shutdown timer is removed altogether (you can see it has been crossed out). That means the computer will only shutdown when the UPS battery level is critical. If it is what you want then it is ok. But I would like to have Proxmox shutdown before reaching critical as shutting down all VMs then shutting down itself still consumes some time and power. Answer from kingman1234 on reddit.com