As your VPS behaves in a similar manner to a physical server, the commands 'shutdown -r' and 'reboot' provide a means of rebooting your account if there is a problem. In order to give the above commands, you must login via a SSH session. Or login to your control panel and issue a reboot from there. However, sometimes this is not possible, so how can you have your server rebooted? You can contact support or you can do it yourself using the Virtuozzo PowerPanel, VZPP.

You access VZPP via the web at http://your_ip_address:4643/. You login using the root username and the root password for your account. This is the same login you would use for a SSH session for the user root. VZPP will provide you the ability to start/stop/restart your server. It also allows you to examine the resources and processes for your server. In fact, if there is a run-away process which is preventing you from accessing your server, then you can simply kill it off without having to perform a reboot to gain access.

There are also links which access the interface and the Support ticket submission area.