A system comprising: a management apparatus of a network including servers on which virtual network functions operate; a first server including a first central processing unit, CPU, and a first programmable logic circuit, and running a first hypervisor, and a second server including a second CPU and a second programmable logic circuit, and running a second hypervisor, wherein the management apparatus comprising: a storage means (102, 103) that stores: circuit information to be loaded into programmable logic circuits; and information indicating a correspondence between at least one virtual network function operating on a server and a programmable logic circuit capable of operating at least part of a virtual network function; and a control means that causes the first and second servers to perform live migration of a virtual network function operated by a programmable logic circuit of the first server to the second server, based on the information indicating the correspondence; wherein the live migration of the virtual network function is controlled by the control means: configuring the second programmable logic circuit on the second server using the same circuit information as that of the first programmable logic circuit of the first server; instructing the first server to change a processing mode of the virtual network function from the first programmable logic circuit to the first CPU; instructing the first and second servers to perform the live migration of the virtual network function from the first server to the second server using the first and second hypervisors; and instructing the second server to link the virtual network function with the second programmable logic circuit to allow the virtual network function to use the second programmable logic circuit. a management apparatus of a network including servers on which virtual network functions operate; a first server including a first central processing unit, CPU, and a first programmable logic circuit, and running a first hypervisor, and a second server including a second CPU and a second programmable logic circuit, and running a second hypervisor, wherein the management apparatus comprising: a storage means (102, 103) that stores: circuit information to be loaded into programmable logic circuits; and information indicating a correspondence between at least one virtual network function operating on a server and a programmable logic circuit capable of operating at least part of a virtual network function; and a control means that causes the first and second servers to perform live migration of a virtual network function operated by a programmable logic circuit of the first server to the second server, based on the information indicating the correspondence; wherein the live migration of the virtual network function is controlled by the control means: configuring the second programmable logic circuit on the second server using the same circuit information as that of the first programmable logic circuit of the first server; instructing the first server to change a processing mode of the virtual network function from the first programmable logic circuit to the first CPU; instructing the first and second servers to perform the live migration of the virtual network function from the first server to the second server using the first and second hypervisors; and instructing the second server to link the virtual network function with the second programmable logic circuit to allow the virtual network function to use the second programmable logic circuit. a storage means (102, 103) that stores: circuit information to be loaded into programmable logic circuits; and information indicating a correspondence between at least one virtual network function operating on a server and a programmable logic circuit capable of operating at least part of a virtual network function; and a control means that causes the first and second servers to perform live migration of a virtual network function operated by a programmable logic circuit of the first server to the second server, based on the information indicating the correspondence; wherein the live migration of the virtual network function is controlled by the control means: configuring the second programmable logic circuit on the second server using the same circuit information as that of the first programmable logic circuit of the first server; instructing the first server to change a processing mode of the virtual network function from the first programmable logic circuit to the first CPU; instructing the first and second servers to perform the live migration of the virtual network function from the first server to the second server using the first and second hypervisors; and instructing the second server to link the virtual network function with the second programmable logic circuit to allow the virtual network function to use the second programmable logic circuit. configuring the second programmable logic circuit on the second server using the same circuit information as that of the first programmable logic circuit of the first server; instructing the first server to change a processing mode of the virtual network function from the first programmable logic circuit to the first CPU; instructing the first and second servers to perform the live migration of the virtual network function from the first server to the second server using the first and second hypervisors; and instructing the second server to link the virtual network function with the second programmable logic circuit to allow the virtual network function to use the second programmable logic circuit.