Patent ID: 8112527

Claim:
A virtual machine management apparatus connected to a plurality of server devices via a network, comprising: one or more computers, the one or more computers including: an allocation rule table that stores a plurality of scores, each score for each of combinations of types of virtual machines, each score indicating appropriateness of a condition that the combination of types of virtual machines is to be allocated to the same server device, each score being set for each of the combinations of any number of types of virtual machines among a plurality of the virtual machines, and each score being higher in a case of less resource conflicts and more communications with each other; a virtual machine allocation determination unit that: selects one or more server devices to which a new virtual machine can be allocated, computes an index value in a case where the new virtual machine is allocated to each of the selected server devices with use of the score, determines a sever device as an allocation target for the new virtual machine with reference to the computed index value that defines maximum value of the score differences, and selects the determined server device that can ensure a resource required for the new virtual machine at present as a server device to which the new virtual machine can be allocated; and a virtual machine migration determination unit that: selects a server device as an allocation target for the new virtual machine that can ensure a resource required at present from a sever device from which an existing virtual machine has been migrated and a server device to which the existing virtual machine has been migrated, irrespective of the present resource, wherein the virtual machine migration determination unit is called by the virtual machine allocation determination unit when there is no server device that can ensure a resource required for the new virtual machine at present.