Virtual machine fault-tolerant method based on KVM virtualization

The invention provides a virtual machine fault-tolerant method based on KVM virtualization. The method comprises the steps that first, a main host node and an auxiliary host node share a sharing file system where a virtual machine magnetic disk is placed; second, an auxiliary virtual machine is started on an auxiliary host node and is used as a mirror image virtual machine of a main virtual machine; third, the main virtual machine sends a data synchronous request actively; fourth, the main virtual machine and the auxiliary virtual machine enter a circulating synchronous stage; and fifth, after fault-tolerant triggering, the auxiliary virtual machine starts a virtual CPU. A virtual fault-tolerant function is controlled at a virtual layer, when a main node is abnormal, a virtual machine course can be switched to a bypass backup node quickly, influence on service in a virtual machine is avoided, and the effect of seamless fault tolerance is achieved.