Ubuntu 12.04 LTS virtual machine can't be shutdown from the host when no one is logged in

[compdoc]

> When i shutdown the host i'd like to have the vm also shutting down.

Although apt-get upgrades may replace it occasionally, what I do is modify
the file   /etc/acpi/powerbtn.sh   to be like so:


#!/bin/sh
# /etc/acpi/powerbtn.sh
# Initiates a shutdown when the power putton has been
# pressed.


# If all else failed, just initiate a plain shutdown.
/sbin/shutdown -h now "Power button pressed"