A disclosed example is a network system including physical nodes. The network system provides a virtual network system including virtual nodes allocated computer resources of the physical nodes. In a case where the network system performs migration of a first virtual node for executing service using computer resources of a first physical node to a second physical node, the network system creates the communication paths for connecting the second physical node and the neighboring physical nodes on the physical links, starts the service executed by the first virtual node using the computer resources secured by the second physical node, switches communication paths to the created communication paths for switching the virtual links.