If you have a problem when you can't reboot or shutdown your VM with shutdown -r now
reboot now
etc, you can force reboot with this command :
sudo -i
echo s > /proc/sysrq-trigger
echo u > /proc/sysrq-trigger
echo b > /proc/sysrq-trigger
- That command is forcly reboot your OS, please ensure you save your work like (unmount, sychronize, etc) before exec thats command.