Some (small) cosmetics 

Hi,

I found your script as I was searching for an easy way to power down my testing server in the evening. To fit my needs I changed some small things namely:

- set maintenance mode first
just to prevent other machines from powering up, while I want to power down.

- reduced wait time and higher the times a shutdown is tried
also the script would always wait a full minute even if a machine immediately powers down.

- changed query for vmid
I have some annotations in my machines, with the old query he also wanted to power down my annotations

- ignore machines that are already in suspended mode
do what it says.

I hope you find this helpful as well.