Patent Publication Number: US-2019179671-A1

Title: Information processing apparatus and information processing system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2017-234834, filed on Dec. 7, 2017, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The embodiments discussed herein are related to an information processing apparatus and an information processing system. 
     BACKGROUND 
     By allocating a predetermined amount of resources to a user before execution of a task based on detection of connection to a virtual machine by the user, a problem of shortage of resources at the time of executing the task is solved. Applications are stably operated by regularly collecting utilization situations of resources, allocating resources necessary for running virtual machines to the virtual machines, and allocating extra resources to the virtual machines according to the priority of the applications. For example, in a cloud system, by proposing to a user a plan with the allocated resource amount that has been reduced based on utilization situations of resources and by allowing the user to select the proposed plan, the idleness of resources increases and the extension of resources addition is suppressed. 
     Related techniques are disclosed in, for example, Japanese Laid-open Patent Publication Nos. 2014-099036 and 2005-309644, and International Publication Pamphlet No. WO 2017/051474. 
     SUMMARY 
     According to an aspect of the present invention, provided is an information processing apparatus including a memory and a processor coupled to the memory. The processor is configured to calculate a surplus resource amount which is an amount of usable unused resources of a computer. The usable unused resources are unused resources usable by one or more users who execute information processing using resources of the computer. The processor is configured to determine an allocated resource amount to be allocated to a first user among the one or more users based on the surplus resource amount and a situation of using the resources by the one or more users. 
     The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a view illustrating an information processing system according to a first embodiment; 
         FIG. 2  is a view illustrating an example of an operation of an information processing apparatus illustrated in  FIG. 1 ; 
         FIG. 3  is a view illustrating an example of an operation flow of the information processing apparatus illustrated in  FIG. 1 ; 
         FIG. 4  is a view illustrating an information processing system according to a second embodiment; 
         FIG. 5  is a view illustrating an example of an operation of a management server illustrated in  FIG. 4 ; 
         FIG. 6  is a view illustrating an example of a fee plan changed by the operation of the management server illustrated in  FIG. 5 ; 
         FIG. 7  is a view illustrating an example of an operation of collecting resource use rates in a determination period illustrated in  FIG. 6 ; 
         FIG. 8  is a view illustrating an example of correcting a collected result illustrated in  FIG. 7  and summarizing it into a change for each time within the determination period; 
         FIG. 9  is a view illustrating a first example of an operation of changing allocation of resources of plural users sharing a processing server in the management server illustrated in  FIG. 4 ; 
         FIG. 10  is a view illustrating a second example of an operation of changing allocation of resources of plural users sharing a processing server in the management server illustrated in  FIG. 4 ; 
         FIG. 11  is a view illustrating a third example of an operation of changing allocation of resources of plural users sharing a processing server in the management server illustrated in  FIG. 4 ; 
         FIG. 12  is a view illustrating an example of an operation for independently changing allocation of resources of plural users in the management server illustrated in  FIG. 4 ; 
         FIG. 13  is a view illustrated an example of an operation flow of the management server illustrated in  FIG. 4 ; 
         FIG. 14  is a view illustrating an example of a screen displayed on a terminal device operated by a user in steps S 30  and S 44  illustrated in  FIG. 13 ; 
         FIG. 15  is a view illustrating an example of an operation of a management server in a third embodiment of the information processing system; 
         FIG. 16  is a view illustrating an example of a fee plan changed by the operation of the management server illustrated in  FIG. 15 ; 
         FIG. 17  is a view illustrating an example of an operation flow of the management server that executes the operation illustrated in  FIG. 15 ; 
         FIG. 18  is a view illustrating an example of a screen on which a user inputs a feeling of use to a terminal device; 
         FIG. 19  is a view illustrating an example of a screen displayed on a terminal device operated by a user in step S 44  illustrated in  FIG. 17 ; 
         FIG. 20  is a view illustrating an example of an operation of a management server in a fourth embodiment of the information processing system; 
         FIG. 21  is a view illustrating an example of a fee plan changed by the operation of the management server illustrated in  FIG. 20 ; 
         FIG. 22  is a view illustrating an example of an operation flow of THE management server that executes the operation illustrated in  FIG. 20 ; and 
         FIG. 23  is a view illustrating an example of a hardware configuration of the information processing apparatus illustrated in  FIG. 1  and the management server illustrated in  FIG. 4 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In an information processing system that allocates resources of a computer to a user according to a fee plan selected by the user, when the fee plan is changed, the resources of the computer according to a new fee plan are allocated to the user. The resource amount of the computer to be allocated to the user is predetermined in accordance with the fee plan. Therefore, even when there is a surplus resource in the computer, resources other than the resources corresponding to the fee plan are not allocated to the user and the resources of the computer may not be used effectively. 
     Hereinafter, embodiments will be described with reference to the drawings. 
       FIG. 1  illustrates an information processing system according to a first embodiment. The information processing system  100  illustrated in  FIG. 1  includes a computer  1  such as a server that executes information processing, and an information processing apparatus  2  such as a management server that manages the computer  1 . The computer  1  is used to provide services such as a cloud service, and includes various resources, for example, a processor (not illustrated) such as a CPU (Central Processing Unit), a memory such as a main storage device, and a disk device. 
     The information processing apparatus  2  allocates resources RS (RSa and RSb) of the computer  1  to users US (USa and USb) using the computer  1 . Further, the information processing apparatus  2  proposes a fee plan for each user US based on the utilization situations of the resources RS that executes information processing. Terminal devices  3  ( 3   a  and  3   b ) operated respectively by the users US are connected to the information processing device  2  via, for example, a network (not illustrated). The terminal devices  3  cause the resources RS of the computer  1  to execute information processing based on the operation by the users US via the information processing apparatus  2 . 
     The information processing apparatus  2  includes a generation unit  2   a , a calculation unit  2   b , a determination unit  2   c  that includes a first determination unit  2   d  and a second determination unit  2   e , an interface unit  2   f  and an allocation changing unit  2   g . The generation unit  2   a , the calculation unit  2   b , the determination unit  2   c , the interface unit  2   f , and the allocation changing unit  2   g  operate for each user. An example of operations of the generation unit  2   a , the calculation unit  2   b , the determination unit  2   c , the interface unit  2   f , and the allocation changing unit  2   g  will be described with reference to  FIG. 2 . 
     For example, the functions of the generation unit  2   a , the calculation unit  2   b , the determination unit  2   c , the interface unit  2   f , and the allocation changing unit  2   g  are implemented by the information processing apparatus  2  that executes a program stored in a memory (not illustrated). The functions of the generation unit  2   a , the calculation unit  2   b , the determination unit  2   c , the interface unit  2   f  and the allocation changing unit  2   g  may be implemented by hardware such as FPGA (Field-Programmable Gate Array) included in the information processing apparatus  2 . 
       FIG. 2  illustrates an example of the operation of the information processing apparatus  2  illustrated in  FIG. 1 . The operation illustrated in  FIG. 2  is executed for each resource RS allocated to a user US. In the example illustrated in  FIG. 2 , a terminal device  3  ( FIG. 1 ) operated by a user US uses a resource RS previously allocated to the computer  1  to cause the computer  1  to execute information processing ((a) of  FIG. 2 ). A thick hatched rectangle indicates the use amount of resources used in information processing, among pre-allocated resource amounts. For example, the thick hatched rectangle indicates the use rate of the pre-allocated resources in a processor, which is one type of resources of the computer  1 . The thick hatched rectangle may indicate the use rate (use amount) of a memory of the computer  1  or the use rate (use amount) of a disk device of the computer  1 . 
     In a preset determination period, the generation unit  2   a  uses the use rate of the resource RS to monitor the use situation of the resource RS and calculates an appropriate resource amount based on the use situation. When the use rate of the resource RS is lower than a preset use rate lower limit, the generation unit  2   a  sets the use lower limit as the use rate of the resource RS. Then, the generation unit  2   a  generates new fee plans P 1  and P 2  corresponding to the appropriate resource amount ((b) of  FIG. 2 ). For example, the fee plan P 1  corresponds to an appropriate resource amount and the fee plan P 2  corresponds to a resource amount which is larger by a predetermined amount than the appropriate resource amount. The generation unit  2   a  may generate one fee plan or may generate three or more fee plans. 
     When the resource amount allocated to the user US has no margin for the use amount of resources used for the information processing, the generation unit  2   a  generates a fee plan that increases the allocated resource amount to raise the use fee. When the resource amount allocated to the user US has a margin for the use amount of resources used for the information processing, the generation unit  2   a  generates a fee plan that decreases the allocated resource amount to lower the use fee.  FIG. 2  illustrates an example of a case where the resource amount allocated to the user US has a margin for the use amount of d resources used for the information processing. 
     The calculation unit  2   b  calculates a surplus resource amount that is a resource amount of an unused resource available to the user US among the resources of the computer  1  ((c) of  FIG. 2 ). When the generation unit  2   a  generates a fee plan for decreasing the allocated resource amount, the surplus resource amount includes a decrease in the allocated resource amount. 
     The first determination unit  2   d  determines a distribution resource amount which is a resource amount allocated to a user US among the surplus resource amount calculated by the calculation unit  2   b , for each fee plan generated by the generation unit  2   a  ((d) of  FIG. 2 ). For example, the distribution resource amount is allocated to the user US at no charge. 
     The second determination unit  2   e  determines the sum of the basic resource amount corresponding to the fee plan generated by the generation unit  2   a  and the distribution resource amount determined by the first determination unit  2   d  as an allocated resource amount to be allocated to the user US ((e) of  FIG. 2 ). That is, the determination unit  2   c  determines a new allocated resource amount (including a distribution resource amount) to be allocated to the user US based on the surplus resource amount calculated by the calculation unit  2   b  and the use situation of resources by the user US. By returning some of unused resources in the computer  1  to the user US, it is possible to effectively use the resources of the computer  1 . 
     The interface unit  2   f  presents the distribution resource amount (+3%, +5%) determined by the first determination unit  2   d  to the user US together with the fee plans P 1  and P 2  generated by the generation unit  2   a  ((f) of  FIG. 2 ). The presentation to the user US is performed by displaying the fee plans P 1  and P 2  and the distribution resource amount on the display unit of the terminal device  3 . Here, “+3%” indicates that 3% of the basic resource amount is added, and “+5%” indicates that 5% of the basic resource amount is added. 
     When a resource is a memory or a disk device, the distribution resource amount may be indicated by storage capacity. Then, the interface unit  2   f  receives information indicating a fee plan selected by the user US (P 2  in this example) via the terminal device  3 . That is, the interface unit  2   f  causes the user US to select a fee plan. 
     The allocation changing unit  2   g  changes an allocated resource amount available for the user US by allocating the basic resource amount and the distribution resource amount corresponding to the new fee plan P 2  selected by the user US to the computer  1  ((g) of  FIG. 2 ). Then, the operation of the resource RS in the new fee plan P 2  to which the distribution resource amount (+5%) available at no charge is added is started ((h) of  FIG. 2 ). That is, the user US executes information processing using the resource RS whose allocated resource amount has been changed. 
     In addition to the basic resources corresponding to the fee plan, the user US can execute the information processing using a resource indicated by the distribution resource amount, thereby further improving the processing performance of the information processing as compared with a case where only the basic resource is used. In the meantime, a service provider that provides a service such as a cloud service using the resources of the computer  1  can strengthen the service to the user US. 
     Thereafter, the information processing apparatus  2  executes a process of monitoring the use situation of the resource RS in the next determination period, a process of generating a new fee plan, and a process of calculating a surplus resource amount. Further, the information processing apparatus  2  executes a process of determining an allocated resource amount to be allocated to the user US (including a distribution resource amount), and a process of causing the user US to select a fee plan. By changing the distribution resource amount together with the fee plan for each determination period, the user US can use resources of an amount obtained by adding the distribution resource amount to the proper basic resource amount calculated by the generation unit  2   a  according to the resource use situation. As a result, the user US can cause the computer  1  to execute information processing without feeling a stress such as an increase in processing time due to insufficient processing performance. 
       FIG. 3  illustrates an example of an operation flow of the information processing apparatus  2  illustrated in  FIG. 1 . That is,  FIG. 3  illustrates an example of an information processing method by the information processing apparatus  2  and a program executed by the information processing apparatus  2 . The operation flow illustrated in  FIG. 3  is executed for each resource RS allocated to the user US. 
     First, in step S 10 , the information processing apparatus  2  collects the use rates (usage amounts) of resources in the determination period illustrated in  FIG. 2 . Next, in step S 12 , when the determination period has elapsed, the information processing apparatus  2  moves the process to step S 14 . When the determination period has not elapsed, the information processing apparatus  2  returns the process to step S 10 . 
     In step S 14 , the information processing apparatus  2  generates a new fee plan to be proposed to the user US based on the use situation of the resource RS. Next, in step S 16 , the information processing apparatus  2  calculates an unused surplus resource amount available for the user US among the resources of the computer  1 . Next, in step S 18 , the information processing device  2  determines a distribution resource amount that can be distributed to the user US from the surplus resource amount. 
     In step S 20 , the information processing apparatus  2  determines the sum of the basic resource amount corresponding to the fee plan generated in step S 14  and the distribution resource amount determined in step S 18  as an allocated resource amount to be allocated to the user US. Next, in step S 22 , the information processing apparatus  2  presents the distribution resource amount determined in step S 18  to the user US together with the fee plan generated in step S 14  to cause the user US to select a fee plan. Next, in step S 24 , the information processing apparatus  2  changes the resource amount available for the user US by allocating the allocated resource amount (including the distribution resource amount) corresponding to the fee plan selected by the user US to the computer  1 , and returns the process to step S 10 . That is, the process illustrated in  FIG. 3  is repeated for each determination period that is a predetermined period. 
     As described above, in the first embodiment illustrated in  FIGS. 1 to 3 , the following effects can be obtained. In the information processing apparatus  2  that allocates the resources of the computer  1  to the user US according to the fee plan selected by the user US, it is possible to return the surplus of the resources to the user US, thereby effectively utilizing the surplus resources not used in the computer  1 . 
     In addition to the basic resources corresponding to the fee plans, the user US can execute the information processing using the resources corresponding to the allocation resource amount which is a portion of the surplus resource amount. As a result, it is possible to further improve the processing performance of information processing to be executed by the computer  1  as compared with the case where only the basic resources are used. Therefore, the user US can cause the computer  1  to execute the information processing without feeling a stress such as an increase in processing time due to insufficient processing performance. A service provider that provides a service such as a cloud service using the resources of the computer  1  can strengthen the service to the user US by returning a portion of the surplus resource amount to the user US. 
       FIG. 4  illustrates an information processing system according to a second embodiment. Detailed description of the same or similar elements as those of the information processing system  100  illustrated in  FIG. 1  will be omitted. The information processing system  100 A illustrated in  FIG. 4  is used, for example, for a service such as a cloud service that provides computer resources via a network NW. Although not particularly limited, IaaS (Infrastructure as a Service) is provided as the cloud service. 
     The information processing system  100 A includes plural processing servers  10  capable of operating plural virtual machines VM for executing information processing, and a management server  20  managing the processing servers  10  to implement a service such as a cloud service. Only one processing server  10  may be used. The processing servers  10  and the management server  20  are interconnected via a network LNW. Each processing server  10  is an example of a computer that executes information processing, and the management server  20  is an example of an information processing apparatus. 
     Each processing server  10  includes a processor  14  such as a CPU (Central Processing Unit) including plural processor cores  12 , a storage device  16  and a disk device  18  connected to the processor  14 . The storage device  16  includes, for example, a memory module including plural SDRAM (Synchronous Dynamic Random Access Memory). The disk device  18  includes an HDD (Hard Disk Drive) or an SSD (Solid State Drive). The processing server  10  executes a control program for implementing a virtual machine such as a hypervisor stored in the storage device  16  based on an instruction from the management server  20 . By executing the control program, physical resources such as the processor core  12 , the storage device  16 , and the disk device  18  are divided as virtual resources and operate as virtual machines VM. For example, a virtual resource includes a virtual processor core virtualizing the processor core  12 , a virtual storage device virtualizing the storage device  16 , and a virtual disk device virtualizing the disk device  18 . 
     The management server  20  is connected to terminal devices  38  via the network NW such as the Internet or an intranet. The management server  20  includes a new allocation unit  22 , a collection unit  24 , a generation unit  26 , a calculation unit  28 , a determination unit  30 , an interface unit  32 , and an allocation changing unit  34 . The functions of the new allocation unit  22 , the collection unit  24 , the generation unit  26 , the calculation unit  28 , the determination unit  30 , the interface unit  32 , and the allocation changing unit  34  will be described with reference to  FIG. 5 . 
     The new allocation unit  22 , the collection unit  24 , the generation unit  26 , the calculation unit  28 , the determination unit  30 , the interface unit  32 , and the allocation changing unit  34  are implemented by a processor such as a CPU of the management server  20  executing a program. The new allocation unit  22 , the collection unit  24 , the generation unit  26 , the calculation unit  28 , the determination unit  30 , the interface unit  32 , and the allocation changing unit  34  may be implemented by hardware such as FPGA of the management server  20 . 
       FIG. 5  illustrates an example of an operation of the management server  20  illustrated in  FIG. 4 . The operation illustrated in  FIG. 5  is started for each user on the basis that a user of a virtual machine VM applied for use of a service such as a cloud service. 
     First, the management server  20  receives an application for use of a service from the terminal device  38  operated by the user via the interface unit  32  ((a) of  FIG. 5 ). For example, the interface unit  32  transmits information on a web page that explains the contents of the service based on a request from the terminal device  38 . The interface unit  32  receives information indicating that an application button for use in the web page has been pressed by the user&#39;s operation, and information on a determination period selected by the user. The determination period corresponds to a cycle for reviewing a fee plan to be described later. An example of a selection period selection screen displayed on the screen of the terminal device  38  is illustrated in  FIG. 14 . 
     The new allocation unit  22  allocates a predetermined settable maximum resource amount to a virtual machine VM to be newly operated based on the application for use from a new user using the processing server  10  ((b) of  FIG. 5 ). The maximum resource amount is determined based on the maximum amount of resources of a service provided in the past, for example, and is a resource sufficient for most users who use the service. After a resource is allocated to the virtual machine VM by the new allocation unit  22 , the operation of the virtual machine VM is started, and the virtual operation period of the service is started. 
     By setting an allocated resource amount allocated at the start of service to a value sufficient for most users, the users can omit the calculation of the resource amount necessary for the service (such as the design of deployment of the cloud service, etc.). As a result, the burden on the user at the start of the service can be reduced. 
     After the service operation by the virtual machine VM is started, the collection unit  24  collects the use rates (use amounts) of various resources in a determination period set by the user ((c) of  FIG. 5 ). For example, the collection unit  24  collects the use rates of the virtual processor cores, virtual storage devices, and virtual disk devices on the virtual machine VM. The collection unit  24  may collect only the use rate of a virtual processor core having the influence on the performance of the virtual machine VM greater than the other virtual processor cores. In the following description, an example will be described in which the use rate of a virtual processor cores is collected and an allocated resource amount of the virtual processor cores is changed. 
     Based on the use rates of various resources collected by the collection unit  24  during the determination period, the generation unit  26  generates a new fee plan corresponding to the basic resource amount that can operate a service without degrading the performance ((d) of  FIG. 5 ). For example, the generation unit  26  generates plural fee plans having different basic resource amounts. 
     The calculation unit  28  calculates a surplus resource amount in each of the active virtual machines VM (virtual surplus resource amount) based on the basic resource amount that can be used in the new fee plan generated by the generation unit  26  ((e) of  FIG. 5 ). The virtual surplus resource amount corresponds to a difference between the basic resource amount corresponding to the new fee plan and the allocated resource amount corresponding to the original fee plan, which is calculated by subtracting the basic resource amount corresponding to the new fee plan from the allocated resource amount corresponding to the original fee plan. When the difference in resource amount is negative, the virtual surplus resource amount is set to “0”. The virtual surplus resource amount is an example of a first surplus resource amount. 
     Further, the calculation unit  28  calculates a resource not used by the virtual machine VM and the hypervisor among the resources of the processing server  10  as a surplus resource amount (physical surplus resource amount). The physical surplus resource amount is an example of a second surplus resource amount. Then, the calculation unit  28  sets the sum of the virtual surplus resource amount and the physical surplus resource amount as a surplus resource amount. 
     Based on the basic resource amount corresponding to the fee plan generated by the generation unit  26 , the determination unit  30  determines a distribution resource amount that is a resource amount that can be distributed to the user of the virtual machine VM among the surplus resource amounts calculated by the calculation unit  28 . That is, the determination unit  30  determines a distribution resource amount to be added to the basic resource amount in the new fee plan. Then, the determination unit  30  determines the sum of the basic resource amount corresponding to the fee plan generated by the generation unit  26  and the distribution resource amount as an allocated resource amount to be allocated to the user ((f) of  FIG. 5 ). The determination unit  30  that determines the distribution resource amount is an example of a first determination unit, and the determination unit  30  that determines the sum of the basic resource amount corresponding to the fee plan and the distribution resource amount as an allocated resource amount to be allocated to the user  30  is an example of a second determination unit. Hereinafter, the distribution resource amount is also referred to as an additional resource amount. 
     The interface unit  32  transmits the information indicating the new fee plan to the terminal device  38  used by the user together with the additional distribution resource amount determined by the determination unit  30  and presents the new fee plan and the additional distribution resource amount on the screen of the terminal device  38  ((g) of  FIG. 5 ). For example, the user uses an input device such as a mouse to select whether to approve the new fee plan presented on the screen ((h) of  FIG. 5 ). When plural fee plans are presented, the user selects one of the plural fee plans. The interface unit  32  receives information indicating the fee plan selected by the user from the terminal device  38  via the network NW. 
     The allocation changing unit  34  changes the allocated resource amount to the virtual machine VM based on the information indicating the fee plan received by the interface unit  32  from the terminal device  38  ((i) of  FIG. 5 ). That is, the operation of the service in the fee plan selected by the user is started. Thereafter, the collection unit  24  collects the use rate of the resource corresponding to the new fee plan. The collection of use rates of various resources is executed during a determination period. Then, the management server  20  repeatedly performs a process of generating a fee plan, a process of calculating a surplus resource amount, a process of determining an additional distribution resource amount, a process of presenting and selecting a new fee plan, and a process of changing an allocated resource amount. 
       FIG. 6  illustrates an example of a fee plan changed by the operation of the management server  20  illustrated in  FIG. 5 . Detailed description of the same operation as in  FIG. 5  will be omitted. After receiving the application for use of the service including selection of a determination period, the management server  20  allocates the settable maximum resource amount to the virtual machine VM used by the user and starts a provisional operation ((a) of  FIG. 6 ). The provisional operation is the same as the formal operation which is started after selecting the fee plan, except that the maximum resource amount is allocated, and there is no restriction on using the virtual machine VM. Since the determination period is set by selection of a user US, it differs for each user US. 
     The management server  20  collects the use rates of resources during the determination period of the provisional operation period. Similarly to  FIG. 2 , the thick hatched rectangle indicates a use resource amount (use rate of a virtual processor core) used in information processing for the allocated resource amount allocated in advance to the virtual machine VM. In the provisional operation period, since the maximum resource amount is allocated to the virtual machine VM, there is almost no possibility that the resource use rate will reach 100%. Thereby, the management server  20  can collect a true use rate which is not limited by the upper limit of the use rate. The management server  20  calculates an appropriate basic resource amount based on the resource use rate collected during the determination period and generates a fee plan corresponding to the appropriate basic resource amount. 
     After generating the fee plan, the management server  20  calculates a surplus resource amount (virtual surplus resource amount+physical surplus resource amount). Then, the management server  20  determines an additional resource amount (indicated by a thin hatched rectangle) that can be distributed to the user among the surplus resource amount ((b) of  FIG. 6 ). A method of calculating the additional resource amount will be described with reference to  FIGS. 9 to 12 . 
     The management server  20  presents a fee plan together with the additional resource amount to the user, and causes the user to select the fee plan. For example, the user selects a fee plan D ((c) of  FIG. 6 ). In the example illustrated in  FIG. 6 , the management server  20  presents three fee plans. In the example illustrated in  FIG. 6 , the additional resource amount is the same irrespective of the fee plan, but it may be different depending on the fee plan. Then, the formal operation in the selected fee plan is started ((d) of  FIG. 6 ). 
     In addition to the basic resource amount, an additional resource amount is added to the fee plan. Therefore, for example, even when a resource amount corresponding to the use rate of a virtual processor core exceeds the basic resource amount (indicated by a dotted line in the rectangle) corresponding to the fee plan, the processing performance of the information processing by the virtual processor core is not deteriorated ((e) of  FIG. 6 ). The processing performance of the information processing by the virtual processor core is not deteriorated as long as the resource amount corresponding to the use rate of the virtual processor core does not exceed the allocated resource amount allocated to the user (basic resource amount+additional resource amount). 
     Thereafter, the management server  20  generates a new fee plan based on the use rates of resources collected during the determination period of the provisional operation period, and presents it to the user together with the additional resource amount. Then, the operation of the service is continued by the resource which corresponds to an addition of the basic resource amount corresponding to the fee plan selected by the user and the additional resource amount. 
       FIG. 7  illustrates an example of an operation of collecting resource use rates in the determination period illustrated in  FIG. 6 . For example, the collection unit  24  illustrated in  FIG. 4  collects the use rates of the virtual processor cores on a daily basis for each time zone during the determination period illustrated in  FIG. 6 .  FIG. 7  illustrates the use rate of a virtual processor core when an allocated resource amount of the virtual processor core allocated to the user is assumed to be 100%. For example, when 50% of the resource amount of one virtual processor core is allocated to the user, the value of ½ of the use rate illustrated in  FIG. 7  indicates the use rate of one virtual processor core. 
     The generation unit  26  illustrated in  FIG. 4  detects time zones during which information processing is executed based on a change in use rate for each daily time zone collected by the collection unit  24 . Hereinafter, the time zones during which information processing is executed are also referred to as actual operation time zones. For example, the detection of the actual operation time zones may be executed not only daily, but also at predetermined intervals, such as every day of the week or every week. 
     In the example illustrated in  FIG. 7 , based on a change in use rate, the generation unit  26  determines that information processing is executed at 0 o&#39;clock zone and from 7 o&#39;clock zone to 19 o&#39;clock zone and no information processing is executed from 1 o&#39;clock zone to 6 o&#39;clock zone and from 20 o&#39;clock zone to 23 o&#39;clock zone. The generation unit  26  generates a fee plan based on the maximum use rate among the use rates excluding the peak portion of the peak value in the actual operation time zones at which information processing is determined to be executed. In other words, the peak portion of the peak value of the use rate and the use rate of time zones other than the actual operation time zones are removed from the information used to generate the fee plan. However, the peak value is stored in the storage device  16  or the disk device  18 . 
     For example, the generation unit  26  generates a fee plan based on a resource amount obtained by adding a predetermined amount of margin to a resource amount corresponding to the maximum value excluding the peak portion of the peak value in the resource use rate. Thereby, it is possible to generate a fee plan that minimizes the burden on users&#39; costs. In the meantime, when a fee plan is generated based on a resource amount corresponding to the peak value, the processing performance of the virtual processor core is not sufficiently used in most of the time zones, which increases the wasteful consumption of resources. In addition, when a fee plan is generated based on a resource amount corresponding to the average value including the peak value and the minimum value which is the use rate of the time zones other than the actual operation time zones, the processing performance of the virtual process core will be insufficient in the actual operation time zones. 
     As described with reference to  FIG. 6 , by allocating the settable maximum resource amount to the virtual machine VM, it is possible to substantially eliminate the possibility that the resource use rate in the provisional operation period reaches 100%. Thus, it is possible to prevent the processing performance of information processing using the virtual machine VM from being limited by the upper limit of the use rate. Therefore, the generation unit  26  can propose an optimum fee plan for the user US, which is a fee plan with a predetermined margin in the processing performance. For example, when a resource amount corresponding to 40% illustrated in  FIG. 7  is allocated to the virtual machine VM in the provisional operation period, the use rate peaks in all the actual operation time zones, which makes it difficult to generate the optimum fee plan. 
       FIG. 8  illustrates an example of an operation of correcting the collected result illustrated in  FIG. 7  and summarizing it into a change for each time within the determination period. The upper side of  FIG. 8  represents a graph after executing correction to remove the peak portion of the peak value and the minimum value from the collection result illustrated in  FIG. 7 . As illustrated in the lower side of  FIG. 8 , the generation unit  26  uses the data obtained by correcting the collected result on each day of the determination period to collect a change in use rate of the virtual processor core for each actual operation time zone in the determination period. The lower graph in  FIG. 8  represents a monthly change in use rate of the virtual processor cores at 13 o&#39;clock zone. Then, for example, the generation unit  26  calculates the average value of use rates for each actual operation time zone, and generates a fee plan based on the maximum average value. In addition, the generation unit  26  may detect the maximum value of the use rate and generate a fee plan based on the maximum value. 
       FIG. 9  illustrates a first example of an operation of changing allocation of resources of plural users sharing the processing server  10  in the management server  20  illustrated in  FIG. 4 . In the information processing system  100 A illustrated in  FIG. 4 , for example, it is predetermined in advance that up to four virtual machines VM (VM 1  to VM 4 ) can be allocated to each processing server  10 . 
     The management server  20  allocates one quarter of allocatable physical resources in the processing server  10  to the virtual machine VM used by the user US based on the application for use of the service from each user US (US 1  to US 4 ), and starts a provisional operation. That is, among the entire physical resources of the processing server  10  which starts the provisional operation, physical resources excluding the resources (unallocatable) used by a hypervisor, etc. are equally allocated to the virtual machines VM 1  to VM 4 . 
     In this manner, the management server  20  allocates a predetermined settable maximum resource amount to a newly operated virtual machine VM. Then, the processing server  10  operates four virtual machines VM (VM 1  to VM 4 ) used by the four users US (US 1  to US 4 ). In  FIG. 9 , for ease of explanation, an example where each user US uses one virtual machine VM is illustrated, but one user US may use plural virtual machines VM. The number of virtual machines VM 1  allocated to the processing server  10  is not limited to four. 
     The leftmost side of  FIG. 9  illustrates a state in which the virtual machines VM 1  to VM 4  are allocated and, as a result, there are no free resources. However, it is rare that the virtual machines VM 1  to VM 4  are allocated at the same time, and usually the virtual machines VM 1  to VM 4  are sequentially allocated based on a request from the user US. For example, when the virtual machine VM 1  is allocated first, resources for allocating the virtual machine VM 2  to VM 4  are treated as reserved resources but are not treated as surplus resources. Therefore, in  FIG. 9 , there is no surplus physical resource at the point of time of starting the provisional operation. 
     After the determination period in the provisional operation for each virtual machine VM has elapsed, the management server  20  calculates an appropriate resource amount (shaded) for each virtual machine VM based on the resource use situation. Here, it is assumed that the appropriate resource amount is the basic resource amount allocated in a fee plan generated later. Then, the management server  20  secures a resource amount obtained by subtracting an appropriate resource amount from the initial allocated maximum resource amount as a surplus resource (that is, a surplus resource amount). That is, a surplus resource is generated from the resources allocated to the virtual machine VM. Further, the management server  20  generates a fee plan corresponding to the calculated appropriate resource amount. 
     The management server  20  calculates a resource amount (additional resource amount) to be additionally allocated to the virtual machine VM among the secured surplus resource amounts. In the example illustrated in  FIG. 9 , the additional resource amount is determined according to the ratio of the basic resource amount corresponding to the fee plan set for each virtual machine VM. That is, the additional resource amount is calculated by proportionally dividing the surplus resource amounts according to the basic resource amount corresponding to the fee plan. Then, the operation of the additional resource amount in the new fee plan is started, and a new fee plan is generated after the determination period has elapsed. By proportionally dividing the surplus resource amounts and determining the allocated resource amount to be allocated to each of the plural users US, it is possible to set an appropriate resource amount according to the resource use situation and evenly distribute the surplus resources to the plural users US. 
     Further, the additional resource amount may be calculated by dividing the surplus resource amount by the number of virtual machines VM. Alternatively, the additional resource amount may be set to a predetermined ratio out of the surplus resource amount. The predetermined ratio is a value smaller than 100%, which may be equal to or less than a ratio evenly distributed to the virtual machines VM (25% in the case of four virtual machines VM). 
     In this manner, the management server  20  determines an allocated resource amount to be allocated to the user US based on the surplus resource amount and the use situation of the virtual machine VM by the user US. By distributing the surplus resources at a predetermined ratio, even when determining the allocated resource amount to be allocated to each of the plural users US, it is possible to set an appropriate resource amount according to the resource use situation and fairly distribute the surplus resources to the plural users US. 
       FIG. 10  illustrates a second different example of the operation of changing allocation of resources of the plural users sharing the processing server  10  in the management server  20  illustrated in  FIG. 4 . Detailed description of the same or similar operation as in  FIG. 9  will be omitted. 
     As in  FIG. 9 , the management server  20  allocates up to four virtual machines VM 1  to VM 4  to one processing server  10 . However, the management server  20  allocates one quarter of the resources excluding a predetermined amount (physical surplus resource) from the allocatable physical resources in the processing server  10  to the virtual machine VM used by the user US and starts a provisional operation. That is, the management server  20  allocates a predetermined settable maximum resource amount to a newly operated virtual machine VM. The resource amount of a physical surplus resource not used in the processing server  10  is an example of a second surplus resource amount. 
     After the determination period in the provisional operation has elapsed, the management server  20  calculates an appropriate resource amount for each virtual machine VM based on the resource use situation to secure a surplus resource. In the virtual machine VM 3 , since the appropriate resource amount is equal to the current resource amount allocated to the virtual machine VM 3 , no surplus resource is generated. Next, the management server  20  generates a fee plan corresponding to the calculated appropriate resource amount. The resource amount of the surplus resource secured from the resources allocated to the virtual machine VM is an example of a first surplus resource amount which is a difference between the allocated resource amount corresponding to the original fee plan and the basic resource amount corresponding to the new fee plan. Immediately after the end of the provisional operation period, the allocated resource amount corresponding to the original fee plan is the preset allocable maximum resource amount. 
     Further, the management server  20  calculates a resource amount to be additionally allocated to the virtual machine VM (additional resource amount) from a virtual surplus resource and a physical surplus resource, which are surplus resources secured from the virtual machine VM. In the example illustrated in  FIG. 9 , the additional resource amount is determined according to the ratio of the basic resource amount corresponding to the fee plan set for each virtual machine VM. That is, the additional resource amount is calculated by proportionally dividing the surplus resource amounts according to the basic resource amount corresponding to the fee plan. Then, the operation in the fee plan including the additional resource amount is started, and a new fee plan is generated after the determination period has elapsed. In this way, not only the virtual surplus resource but also the physical surplus resource can be used to determine the additional resource amount to be additionally allocated to the virtual machine VM. 
     In the example illustrated in  FIG. 10 , since the additional resource amount is calculated with the generation of the first fee plan, the physical surplus resource disappears. Therefore, the calculation of the additional resource amount with the generation of the second and subsequent fee plans is executed based on the surplus resource generated in each virtual machine VM as in  FIG. 9 . 
       FIG. 11  illustrates a third example of the operation of changing allocation of resources of the plural users sharing the processing server  10  in the management server  20  illustrated in  FIG. 4 . Detailed description of the same or similar operation as in  FIG. 9  will be omitted. 
     As in  FIG. 10 , the management server  20  allocates one quarter of the resources excluding a predetermined amount (physical surplus resource) from the allocatable physical resources in the processing server  10  to the virtual machine VM used by the user US, and starts a provisional operation. That is, the management server  20  allocates a predetermined settable maximum resource amount to the newly operated virtual machine VM. The size of the physical surplus resource is larger than the size of the physical surplus resource in  FIG. 10 . 
     After the determination period in the provisional operation has elapsed, the management server  20  calculates an appropriate resource amount for each virtual machine VM based on the resource use situation to secure a surplus resource. However, a surplus resource secured from the resources of the virtual machine VM is not used for a resource to be additionally distributed, and is held as a physical surplus resource for additional distribution after the next determination period. Since the appropriate resource amount of the virtual machine VM 3  is larger than the current resource amount allocated to the virtual machine VM 3 , the allocated resource amount is insufficient. The appropriate resource amount of the virtual machine VM 4  is equal to the current resource amount allocated to the virtual machine VM 4 . Therefore, no surplus resources are generated in the virtual machines VM 3  and VM 4 . Next, the management server  20  generates a fee plan corresponding to the calculated appropriate resource amount. 
     In addition, the management server  20  calculates a resource amount (additional resource amount) to be additionally allocated to the virtual machine VM from the already secured physical surplus resources. That is, in  FIG. 11 , the additional resource amount is allocated from the physical surplus resource without using the surplus resource of the virtual machine VM. Then, the operation in the fee plan including the additional resource amount is started, a new fee plan is generated after the determination period has elapsed, and the additional resource amount is calculated from the physical surplus resources. 
       FIG. 12  illustrates an example of an operation for independently changing the allocation of resources of plural users in the management server  20  illustrated in  FIG. 4 .  FIG. 12  illustrates an example of the operation in the formal operation period in  FIG. 6 . A shaded rectangle indicates an appropriate resource amount as in  FIG. 9 , and a thin hatched rectangle indicates an additional resource amount distributed to the user US as in  FIG. 6 . 
     When the information processing system  100 A provides a service such as a cloud service to the user US, the time when the user US applies for use of a service differs for each user US, and the determination period differs for each user U since it is set by the user US. Therefore, the management server  20  generates a new fee plan asynchronously for each user US. 
     For example, the management server  20  calculates an appropriate resource amount based on the resource use rate of the virtual machine VM 1  used by the user US 1  and generates a new fee plan ((a) of  FIG. 12 ). When a resource amount difference obtained by subtracting the appropriate resource amount from the allocated resource amount corresponding to the original fee plan has a positive value, the management server  20  secures a resource corresponding to the resource amount difference as a surplus resource in a surplus pool ((b) of  FIG. 12 ). 
     The surplus pool is not physically provided in the management server  20  but is represented by, for example, a surplus management table which is allocated to the memory of the management server  20  in order to manage the values of the surplus resource amount. The surplus resource secured in the surplus pool includes at least one of a virtual surplus resource that is a surplus resource of the virtual machine VM and a physical surplus resource that is a resource that can be allocated in a resource other than the resource allocated to the virtual machine VM. 
     The management server  20  calculates an additional resource amount of a resource to be additionally allocated to the virtual machine VM 1  based on the surplus resource secured in the surplus pool. The management server  20  adds the calculated additional resource amount to an appropriate resource amount (e.g., the basic resource amount) included in the new fee plan to make a new allocated resource amount ((c) of  FIG. 12 ). After selecting a fee plan by the user US 1 , the information processing is executed by the virtual machine VM 1  whose allocated resource amount has been changed. 
     Meanwhile, when the resource amount difference obtained by subtracting the appropriate resource amount from the allocated resource amount corresponding to the original fee plan has a negative value, since no surplus resource is generated, the management server  20  does not execute a process of securing a surplus resource in the surplus pool ((d) of  FIG. 12 ). As illustrated in  FIG. 12 , the management server  20  determines an additional resource amount to be added to the new fee plan based on the surplus resource secured in the surplus pool each time the determination period of the virtual machine VM ends. 
     As in the explanation in  FIG. 9 , the management server  20  calculates an additional resource amount that proportionally divides the surplus resource amounts secured in the surplus pool, or calculates an additional resource amount of a ratio that is equal to or less than the ratio that evenly distributes the surplus resource amounts to the virtual machine VM. Thereby, even when the timing of calculating the additional resource amount differs among the virtual machines VM, it is possible to distribute the surplus resources fairly to the plural users US while setting an appropriate resource amount according to the resource use situation. 
       FIG. 13  illustrates an example of an operation flow of the management server  20  illustrated in  FIG. 4 . That is,  FIG. 13  illustrates an example of an information processing method by the management server  20  and a program executed by the management server  20 . The operation flow illustrated in  FIG. 13  is started for each user US based on the fact that the user US has applied for use of a service such as a cloud service. 
     First, in step S 30 , the management server  20  receives a determination period from the user US when applying for use of a service. Next, in step S 32 , the management server  20  allocates the settable maximum resource amount to the virtual machine VM used by the user US and starts a provisional operation. 
     Next, in step S 34 , the management server  20  collects the use rates (use amounts) of the resources allocated to the virtual machine VM used by the user US. Next, in step S 36 , when the determination period has elapsed, the management server  20  moves the process to step S 38 . When the determination period has not elapsed, the management server  20  returns the process to step S 34 . 
     In step S 38 , the management server  20  calculates an appropriate resource amount based on the resource use situation and generates a fee plan based on the calculated appropriate resource amount. Next, in step S 40 , the management server  20  calculates a surplus resource amount which is an unused resource that can be allocated to the virtual machine VM 1  in the processing server  10 . Next, in step S 42 , the management server  20  calculates an additional resource amount to be additionally allocated from the surplus resource to the virtual machine VM. 
     Next, in step S 44 , the management server  20  presents the fee plan generated in step S 14  together with the additional resource amount calculated in step S 42  to the user US via the terminal device  38 . The additional resource amount is included in the fee plan and is substantially at no charge. The management server  20  may indicate that additional resources to be added free of charge to the fee plan are included without presenting the additional resource amount. Further, the management server  20  may present plural additional resource amounts for each fee plan and cause a user to select one of the plural additional resource amounts. 
     Next, in step S 46 , the management server  20  waits until the user US selects a fee plan including the additional resource amount, and moves the process to step S 48  based on the selection of the user US. In step S 48 , the management server  20  allocates a resource including the additional resource amount to the virtual machine VM, and moves the process to step S 34  in order to start an operation in a new determination period. That is, the processes from step S 34  to step S 48  are repeated for each determination period that is a predetermined period. 
       FIG. 14  illustrates an example of a screen displayed on the terminal device  38  operated by the user US in steps S 30  and S 44  illustrated in  FIG. 13 . The management server  20  displays a screen for selecting a determination period for determining an appropriate resource amount on the display unit of the terminal device  38  in step S 30  of receiving the application for use of the service. Although not particularly limited, in the present embodiment, the selectable determination period is one week, two weeks, one month or two months. 
     In addition, in step S 44  of receiving a change in fee plan, the management server  20  displays a screen for selecting a fee plan including the additional resource amount on the display unit of the terminal device  38 . In  FIG. 14 , three fee plans are displayed, but the number of fee plans is not limited to three. In addition, a fee plan with a smaller basic resource amount than the current fee plan may be displayed. Furthermore, in a case where a resource to be added to the basic resource corresponding to the fee plan is a memory or a disk device, the additional resource amount may be indicated by an added storage capacity instead of the increase rate. Instead of displaying the amount of resources to be added, it may be displayed that resources are added for free. 
     As described above, in the second embodiment illustrated in  FIGS. 4 to 14 , the same effects as those of the first embodiment illustrated in  FIGS. 1 to 3  can be obtained. For example, in the management server  20  that allocates the resources of the processing server  10  to the user US according to the fee plan, it is possible to return the surplus of the resources to the user US and effectively utilize the surplus resources not used in the processing server  10 . The user US can improve the processing performance of the information processing to be executed by the processing server  10  as compared with a case where only the basic resource corresponding to the fee plan is used. Further, since the surplus resource amount is allocated to the virtual machine VM, the user US can cause the information processing to be executed in the processing server  10  without feeling a stress such as an increase in processing time due to insufficient processing performance. 
     Furthermore, in the second embodiment illustrated in  FIGS. 4 to 14 , an allocated resource amount to be allocated to each of the plural users US is determined by apportioning the surplus resources or distributing them at a predetermined ratio. Thereby, it is possible to fairly distribute the surplus resources to the plural users US while setting an appropriate resource amount according to the resource use situation. It is possible to use not only the virtual surplus resource in the virtual machine VM but also the additional resource amount to determine an additional resource amount to be additionally allocated to the virtual machine VM. 
     By generating a fee plan based on the resource amount corresponding to the maximum value excluding the peak portion of the peak value of the resource use rate, it is possible to generate a fee plan minimizing the cost burden of the user US. By allocating the settable maximum resource amount to the virtual machine VM, the user US can omit the calculation of the resource amount necessary for the service, thereby reducing the burden on the user US at the start of the service. Further, it is possible to prevent the processing performance of information processing using the virtual machine VM from being limited by the upper limit of the use rate. 
       FIG. 15  illustrates an example of an operation of a management server according to a third embodiment of the information processing system. Detailed description of the same or similar operation as in  FIG. 5  will be omitted. 
     As with the management server  20  illustrated in  FIG. 4 , the management server that executes the operation illustrated in  FIG. 15  includes a new allocation unit  22 , a collection unit  24 , a generation unit  26 , a calculation unit  28 , a determination unit  30 , an interface unit  32  and an allocation changing unit  34 . The functions of the new allocation unit  22 , the collection unit  24 , the generation unit  26 , the calculation unit  28  and the allocation changing unit  34  are the same as the functions described in  FIG. 5 . 
     The configuration of the information processing system including the management server is the same as that of the information processing system  100 A illustrated in  FIG. 4 , and the information processing system  100 A is connected to the terminal device  38  operated by the user via the network NW. Hereinafter, the management server that executes the operation illustrated in  FIG. 15  is referred to as a management server  20 . 
     In  FIG. 15 , a function of collecting from the user the feeling of use of a service such as the service provided by the information processing system  100 A is added to the interface unit  32  ((a) of  FIG. 15 ), as compared with  FIG. 5 . 
     For example, the feeling of use is collected from an end user directly using a service such as a cloud service. The feeling of use may be collected not only from the end user but also from a user such as a system administrator of a company receiving services. 
     Further, as compared with  FIG. 5 , a function of adding an additional resource amount reflecting the collected user&#39;s feeling of use to the fee plan is added to the determination unit  30  ((b) of  FIG. 15 ). For example, the determination unit  30  totals use feeling information indicating the user&#39;s feeling of use collected by the interface unit  32  and increases the additional resource amount as the satisfaction degree of the result of totaling becomes lower. The function of generating a new fee plan reflecting collected user&#39;s feeling of use may be included in the generation unit  26 . In this case, the generation unit  26  also has a function of totaling the use feeling information indicating the user&#39;s feeling of use collected by the interface unit  32 . That is, the determination unit  30  adjusts either the additional resource amount or the basic resource amount corresponding to the new fee plan based on the use feeling information. When presenting a fee plan on the display unit of the terminal device  38 , the interface unit  32  has a function of presenting the totaling result of the user&#39;s feeling of use together ((c) of  FIG. 15 ). 
       FIG. 16  illustrates an example of a fee plan changed by the operation of the management server illustrated in  FIG. 15 . Detailed description of the same or similar processing as in  FIG. 6  will be omitted. The operation in the provisional operation period is the same as in  FIG. 6 , and the user&#39;s feeling of use is not totaled. This is because the information processing is executed using the maximum resource amount in the provisional operation period, so that the user hardly feels dissatisfied with, for example, the processing performance. 
     In the formal operation period, the management server  20  can receive the use feeling information indicating the feeling of use from the user ((a) of  FIG. 16 ). Then, the management server  20  collects the use feeling information received from the user via the terminal device  38  ((b) of  FIG. 16 ). 
       FIG. 18  illustrates a screen displayed on the display unit of the terminal device  38  in order for the user to notify the management server  20  of the feeling of use via the terminal device  38 . 
     The management server  20  totals the collected use feeling information ((c) of  FIG. 16 ). Then, the management server  20  generates a new fee plan corresponding to a resource amount that can operate a service without degrading the performance based on the resource use rate and the totaled use feeling information ((d) of  FIG. 16 ). The subsequent processing is the same as in  FIG. 6 . 
     By using the totaled use feeling information at the time of generating the fee plan, it is possible to generate a fee plan that is less prone to a stress to the user than when mathematically generating a fee plan from the resource use rate. As a result, it is possible to increase the satisfaction degree of the user who causes the processing server  10  to execute the information processing as compared with a case where the user&#39;s feeling of use is not totaled. 
       FIG. 17  illustrates an example of an operation flow of the management server  20  that executes the operation illustrated in  FIG. 15 . That is,  FIG. 17  illustrates an example of an information processing method by the management server  20  and a program executed by the management server  20 . The same or similar processes as in  FIG. 13  are denoted by the same reference numerals and detailed description thereof will not be repeated.  FIG. 17  illustrates the same processing as  FIG. 13 , except that step S 37  is inserted between step S 36  and step S 38  in  FIG. 13 . 
     In step S 37 , the management server  20  totals the use feeling information indicating the user&#39;s feeling of use collected during the determination period. Then, in step S 38 , the management server  20  generates a new fee plan based on the resource use rate and the totaled use feeling information. The management server  20  receives the use feeling information from the terminal device  38  each time the user inputs the feeling of use to the terminal device  38 . 
     Therefore, the process of collecting the user&#39;s feeling of use is not illustrated in  FIG. 17 . Further, as described with reference to  FIG. 16 , the management server  20  does not collect the use feeling from the user during the determination period of the provisional operation period. Therefore, the processing in step S 37  is not included in the operation flow in the provisional determination period. 
       FIG. 18  illustrates an example of a screen on which the user inputs the feeling of use to the terminal device  38 . The screen illustrated in  FIG. 18  is displayed by clicking on, for example, a “use feeling input button” displayed on a separate screen before the user inputs the use feeling. The user selects an item closest to the feeling of use of the user. The screen for inputting the feeling of use is not limited to the display example 1 and the display example 2 illustrated in  FIG. 18 . 
       FIG. 19  illustrates an example of a screen displayed on the terminal device  38  operated by the user in step S 44  illustrated in  FIG. 17 . On the screen are displayed the contents indicating the totaling result of the use feeling from the user in addition to the contents that allow selection of a fee plan including the additional resource amount illustrated on the lower side of  FIG. 14 . Further, as illustrated in  FIG. 19 , a recommended fee plan may be indicated based on the totaling result of use feeling. 
     As described above, the third embodiment illustrated in  FIGS. 15 to 19  can obtain the same effects as those of the first and second embodiments illustrated in  FIGS. 1 to 13 . Further, in the third embodiment illustrated in  FIGS. 15 to 19 , by using the totaled use feeling information at the time of generating the fee plan, it is possible to generate a fee plan that is less prone to a stress to the user than when mathematically generating a fee plan from the resource use rate. As a result, it is possible to increase the satisfaction degree of the user who causes the processing server  10  to execute the information processing as compared with a case where the user&#39;s feeling of use is not totaled. 
       FIG. 20  illustrates an example of an operation of a management server according to a fourth embodiment of the information processing system. Detailed description of the same or similar operation as in  FIG. 5  will be omitted. 
     As with the management server  20  illustrated in  FIG. 4 , the management server that executes the operation illustrated in  FIG. 20  includes a new allocation unit  22 , a collection unit  24 , a generation unit  26 , a calculation unit  28 , a determination unit  30 , an interface unit  32  and an allocation changing unit  34 . The functions of the new allocation unit  22 , the collection unit  24 , the calculation unit  28 , the determination unit  30  and the allocation changing unit  34  are the same as the functions described in  FIG. 5 . 
     The configuration of the information processing system including the management server is the same as that of the information processing system  100 A illustrated in  FIG. 4 , and the information processing system  100 A is connected to the terminal device  38  operated by the user via the network NW. Hereinafter, the management server that executes the operation illustrated in  FIG. 20  is referred to as a management server  20 . 
     In  FIG. 20 , a function of changing an allocated resource amount during the provisional operation period is added, as compared with  FIG. 5 . Since the processing in the formal operation period is the same as in  FIG. 5 , description thereof will not be repeated, and the processing in the provisional operation period will be described below. 
     First, the management server  20  receives an application for use of a service, including information for selecting a review cycle and a determination period from the terminal device  38  operated by the user via the interface unit  32  ((a) of  FIG. 20 ). The review cycle indicates a cycle of changing an allocated resource amount during the provisional operation period. For example, the review cycle corresponds to a period of about one quarter of the determination period or a period of about one half of the determination period. When the determination period is one month, the review cycle is one week or two weeks. The new allocation unit  22  allocates a predetermined settable maximum resource amount to a newly operated virtual machine VM ((b) of  FIG. 20 ). Then, the operation of the service by the virtual machine VM in the provisional operation period is started. 
     Next, the collection unit  24  collects use rates (use amounts) of various resources during the period of the review cycle ((c) of  FIG. 20 ). After completion of the review cycle, the generation unit  26  generates a change plan that changes the service to an allocated resource amount that can operate the service without degrading the performance, based on the use rates of various resources collected by the collection unit  24  ((d) of  FIG. 20 ). 
     Next, the interface unit  32  transmits information indicating the change plan to the terminal device  38  used by the user, and presents the change plan on the screen of the terminal device  38  ((e) of  FIG. 20 ). The user selects whether to approve the change plan presented on the screen ((f) of  FIG. 20 ). When plural change plans are presented, the user selects one of the plural change plans. For example, on the screen for selecting the change plan, “Plan” is displayed instead of “fee plan” on the lower side of  FIG. 14 , and a fee and an increase rate of resource amount are not displayed. 
     The allocation changing unit  34  changes the allocated resource amount to the virtual machine VM based on the information of the change plan received by the interface unit  32  from the terminal device  38  ((g) of  FIG. 20 ). That is, the operation of the service in the change plan selected by the user is started. When the provisional operation period does not end, the collection unit  24  executes a process of collecting use rates (use amounts) of various resources in the provisional operation period ((h) of  FIG. 20 ). In the meantime, when the provisional operation period ends, the collection unit  24  executes a process of collecting use rates (use amounts) of various resources in the formal operation period ((i) of  FIG. 20 ). Then, as in  FIG. 5 , the management server  20  executes a process in the formal operation period. 
       FIG. 21  illustrates an example of a fee plan changed by the operation of the management server  20  illustrated in  FIG. 20 . Detailed description of the same or similar processing as in  FIG. 6  will be omitted. Since the processing in the formal operation period is similar to the processing in the formal operation period illustrated in  FIG. 6 , description thereof will not be repeated, and the processing in the provisional operation period will be described below. 
     In the provisional operation period, in each review cycle, a change plan of an allocated resource amount is generated based on the collected resource use rates ((a) of  FIG. 21 ). In the first review cycle, a portion of resources to which the maximum amount is allocated is released as a surplus resource. Then, the allocated resource amount corresponding to the change plan selected by the user is allocated to the virtual machine VM, and the operation in the provisional operation period is continued ((b) and (c) of  FIG. 21 ). 
     The change of the allocated resource amount is executed for each review cycle during the provisional operation period. When the provisional operation period ends, the operation in the formal operation period is started by the changed allocated resource amount, and a process of generating a fee plan is executed ((d) of  FIG. 21 ). In the formal operation period, as in  FIG. 16 , the user&#39;s feeling of use may be totaled, and a fee plan reflecting the user&#39;s feeling of use may be generated. 
     By reviewing the allocated resource amount plural times based on the use rates of the resources by the user during the provisional operation period, it is possible to release a portion of the resources to which the maximum amount is allocated during the provisional operation period, thereby effectively utilizing the resources of the processing server  10 . For example, when the determination period is one month and the review period is one week, a portion of the resources can be released at the point of time when the first week of the provisional operation period has elapsed. In addition, before the official operation period comes, it becomes possible to converge the allocated resource amount allocated to the virtual machine VM to the optimum resource amount. 
       FIG. 22  illustrates an example of an operation flow of the management server  20  that executes the operation illustrated in  FIG. 20 . That is,  FIG. 22  illustrates an example of an information processing method by the management server  20  and a program executed by the management server  20 . The same or similar processes as in  FIG. 13  are denoted by the same reference numerals, and detailed description thereof will not be repeated.  FIG. 22  illustrates the same processing as  FIG. 13 , except that step S 31  is executed instead of step S 30  in  FIG. 13  and steps S 50  to S 62  are inserted between step S 32  and step S 34  in  FIG. 13 . Further, step S 37  of totaling the user&#39;s feeling of use illustrated in  FIG. 17  may be inserted between step S 36  and step S 38 . In this case, the management server  20  collects the user&#39;s feeling of use during the determination period. 
     In step S 31 , the management server  20  receives a determination period and a review period from the user US when applying for use of a service. Next, in step S 32 , the management server  20  allocates a settable maximum resource amount to the virtual machine VM used by the user, and starts a provisional operation. 
     Next, in step S 50 , the management server  20  collects the use rates (use amounts) of the resources allocated to the virtual machine VM used by the user. Next, in step S 52 , when the review period has elapsed, the management server  20  moves the process to step S 54 . When the review period has not elapsed, the management server  20  returns the process to step S 50 . 
     Next, in step S 54 , the management server  20  calculates an appropriate resource amount for the virtual machine VM based on the resource use situation, and generates a change plan to change the allocated resource amount to the virtual machine VM based on the calculated appropriate resource amount. Next, in step S 56 , the management server  20  presents the change plan generated in step S 54  to the user via the terminal device  38 . 
     Next, in step S 58 , the management server  20  waits until the user selects the change plan, and moves the process to step S 60  based on the selection by the user. 
     In step S 60 , the management server  20  allocates a resource corresponding to the change plan selected by the user to the virtual machine VM. Next, in step S 62 , when the provisional operation period does not end, the management server  20  returns the process to step S 50 . When the provisional operation period ends, the management server  20  moves the process to step S 34  to start the operation in the formal operation period. 
     As described above, the fourth embodiment illustrated in  FIGS. 20 to 22  can obtain the same effects as those of the first, second and third embodiments illustrated in  FIGS. 1 to 18 . Further, in the fourth embodiment illustrated in  FIGS. 20 to 22 , by reviewing the allocated resource amount plural times during the provisional operation period, it is possible to release a portion of the resources to which the maximum amount is allocated during the provisional operation period, thereby effectively utilizing the resources of the processing server  10 . 
       FIG. 23  illustrates an example of a hardware configuration of the information processing apparatus  2  illustrated in  FIG. 1  and the management server  20  illustrated in  FIG. 4 . Since the hardware configurations of the information processing apparatus  2  and the management server  20  are similar to each other, the configuration of the management server  20  will be described below. Note that the computer  1  and the terminal device  3  illustrated in  FIG. 1  and the processing server  10  and the terminal device  38  illustrated in  FIG. 4  also have the same or similar hardware configurations as those in  FIG. 23 . 
     The management server  20  includes a main body  40  such as a mother board, a monitor  50 , a mouse  52  and a keyboard  54  connected to the main body  40 . The main body  40  includes a processor  41  such as a CPU, memories  42  and  43 , a graphic processing unit  44 , a HDD (Hard Disk Drive)  45 , an input interface  46 , an input/output interface  47  and a communication interface  48 , which are interconnected via a bus BUS. The main body  40  may have an FPGA. 
     The processor  41  has plural processor cores  41   a  that execute arithmetic processing. The main unit  40  may have plural processors  41 . Either of the processor cores  41   a  implements the functions of the information processing apparatus  2  illustrated in  FIG. 1  or the management server  20  illustrated in  FIG. 4  by executing a program. When the plural processors  41  are provided in the main body  40 , one of the plural processors  41  may execute the program. 
     For example, the memory  42  is a memory module on which plural SDRAMs are mounted, and the memory  43  is a flash memory. The graphic processing unit  44  outputs, for example, image data to be displayed on the monitor  50  to the monitor  50  based on an instruction from the processor  41 . The HDD  45  holds, for example, various programs to be executed by the processor  41 . The processor  41  executes various programs transferred from the HDD  45  to the memory  42 . 
     The input interface  46  transmits signals received from the input devices such as the mouse  52  and the keyboard  54  to the processor  41 . The input/output interface  47  reads information such as various programs or data from a recording medium  56  based on an instruction from the processor  41 , and writes the read information in, for example, the HDD  45 . Further, the input/output interface  47  reads the information stored in, for example, the HDD  45  based on an instruction from the processor  41 , and writes the read information in the recording medium  56 . The recording medium  56  is, for example, a CD (Compact Disc)®, a DVD (Digital Versatile Disc)®, or a USB (Universal Serial Bus) memory. The communication interface  48  exchanges information with other devices connected to the network NW via the network NW. 
     All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to an illustrating of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.