Generally described, aspects of the present disclosure relate to a live update process of the virtual machine monitor during the operation of the virtual machine instances. An update to a virtual machine monitor can be a difficult process to execute because of the operation of the virtual machine instances. Generally, in order to update the virtual machine monitor, the physical computing device needs to be rebooted, which interrupts operation of the virtual machine instances. The live update process provides for a method of updating the virtual machine monitor without rebooting the physical computing device.