I’ve installed an APC BX950MI-GR and connected it to my Proxmox server via USB.
It works: it turns off the server after x minutes after the power loss and it gets turned off by the command upsdrvctl shutdown, when the powers come back on, the UPS turns on and so does the server.
The problem is if the power comes back after the server receive the power off signal and before the UPS powers off, in this case the UPS simply goes back in the normal state and the server…stays off.
How can I turn it back on?
Thanks!
You would need a third device monitoring both for this edge case. Once the server has been told to shut down, it’s going to shut down.
The third device (also on the UPS, like an Rpi or ESP) can then check for power availability through the UPS and whatever logic you want to apply, can then use wake on lan to the server to power it up once it shuts down.