vmswitch for virsh- shutdown one vm, start another. on shutdown, start the first one again

vmswitcher

#!/bin/bash

# chmod +x and run this script directly, NOT with "bash vmswitcher"
# ./vmswitcher -d to run in background

#Enter your vm-ids here
IDLEVM="powersave-server"
ACTIVEVM="bin10"


LOGFILE="/var/log/vmswitcher.$IDLEVM-$ACTIVEVM.log"
LOCKFILE="/tmp/vmswitcher.$IDLEVM-$ACTIVEVM.lock"

#Prevent multiple executions
if test -f "$LOCKFILE"; then
    echo "Lockfile found. If you're sure, no other version of this script is running, remove it with:" 
    echo "rm $LOCKFILE"
    echo "Exiting"
    exit 1
fi
touch $LOCKFILE

#Daemonize
case "$1" in
    -d|--daemon)
        echo "Shutting down $IDLEVM"
        echo "Starting $IDLEVM"
        echo "Detaching"
        echo "cat $LOGFILE to view output"
        touch $LOGFILE
        rm $LOCKFILE
        $0 < $LOGFILE &> $LOGFILE & disown
        exit 0
        ;;
    *)
        ;;
esac

echo "$(date) Shutting down $IDLEVM"
virsh shutdown $IDLEVM 2>/dev/null

echo "$(date) Waiting for shutdown of $IDLEVM"
until virsh domstate $IDLEVM | grep -q 'shut off'
do
  virsh shutdown $IDLEVM 2>/dev/null
  sleep 5
done

echo "$(date) ...Shutdown. Starting $ACTIVEVM"
virsh start $ACTIVEVM
echo "$(date) ...Started. Wait 1min to $ACTIVEVM to boot"
sleep 60

echo "$(date) ...$ACTIVEVM running. Polling for shutdown."
until virsh domstate $ACTIVEVM | grep -q 'shut off'
do
  sleep 10
done

echo "$(date) ...$ACTIVEVM is shut down. Starting $IDLEVM"
virsh start $IDLEVM

echo "$(date) ...Polling for startup of $IDLEVM"
until virsh domstate $IDLEVM | grep -q 'running'
do
  sleep 1
done
echo "$(date) ...$IDLEVM running. Exit."

rm $LOCKFILE
exit 0

I use this to start my win10-vm and get the "powersave" vm running again, as soon as win10 is shutdown.
Background: Vfio GPU Passthrough with pci id kernel bind to vfio. If no vm is running, power consumption is higher.
The powersave-vm is a simple ubuntu server with nvidia drivers.