In one type of a computing system on which one or more virtual machines (VM) run, a host operating system (OS) is installed, and a hypervisor, which manages the virtual machines, runs on top of or in conjunction with the host OS. The computing system of this type is typically utilized when the computing system is used for purposes other than hosting virtual machines, including running applications directly on top of the host OS.
The host OS may need to reboot for various reasons, such as update of the host OS, installation or update of application software, troubleshooting, addition or update of another hypervisor, and so on. When the host OS reboots, since the power of the computing system is shut off, the hypervisor running on the computing system is forced to close and therefore all sessions that are executing on the virtual machines are forced to stop and thus setting data for the sessions are lost. For that reason, it is desirable to configure the hypervisor so as to maintain the session on virtual machines even across host OS rebooting.