Self-host PVE-UPS

This tool watches UPS units via SNMP using the standard RFC 1628 MIB plus vendor-specific MIBs from APC and CyberPower, or it can read data from a NUT server. When battery levels drop, it powers off Proxmox VE nodes and optionally a Proxmox Backup Server. It runs as a small LXC container (~256 MB RAM) installed by one command on the Proxmox host, or as a multi-arch Docker image. All configuration happens in a browser wizard with live test buttons — no config files to edit. Shutdown uses dedicated Proxmox API tokens that carry just the Sys.PowerMgmt privilege — no SSH access, no agents installed on the hosts. Extras include per-UPS trigger overrides, a visual shutdown-order preview, cluster-wide HA disarm and guest stop (Beta), Ceph maintenance flags (Beta), webhooks for Slack/Discord/Teams/ntfy/custom templates, a read-only REST status endpoint, historical charts with CSV export, and in-place updates from the UI. The logic is safe by default: losing UPS contact only raises an alarm, never starts a shutdown. After install the engine runs in dry-run mode so you can verify everything before arming it.