PVE Host

vim /etc/systemd/logind.conf

IdleAction=suspend
IdleActionSec=30min

systemctl restart systemd-logind

#!/usr/bin/env bash

vmid=100

while true; do
        active_count=$(/usr/sbin/qm satus 100 | grep running | wc -l)
        if [[ $active_count -gt 0 ]]; then
                # inhibit host sleep
                systemd-inhibit --what=sleep \
                                --who="Proxmox Guest" \
                                --why="Guest VM is running" \
                                sleep 30
        fi
        # wait for 1 second before checking againe
        sleep 1
done