System for confirming and cancelling tentative resource reservation within the valid time indicates period during which the tentative reservation request is valid

• US 8,166,484 B2
• Filed: 03/19/2004
• Issued: 04/24/2012
• Est. Priority Date: 03/31/2003
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Kawato, Masahiro
• Primary Examiner(s): An, Meng
• Assistant Examiner(s): ZHE, MENG YAO
• Application Number:
  US10/804,110
• Publication Number:
  US 20040215780A1
• Time in Patent Office: 2,958 Days
• Field of Search: 718/104
• US Class Current: 718/104
• CPC Class Codes: H04L 47/15 in relation to multipoint traffic arrangements for broadcast or multicast in data networks H04L12/18
• CPC Class Codes: H04L 47/70 Admission control; Resource allocation
• CPC Class Codes: H04L 47/724 at intermediate nodes, e.g. resource reservation protocol [RSVP]
• CPC Class Codes: H04L 47/741 Holding a request until resources become available
• CPC Class Codes: H04L 47/826 Involving periods of time
• CPC Class Codes: H04L 67/10 in which an application is distributed across nodes in the network software deployment G06F8/60; multiprogramming arrangements G06F9/46
• CPC Class Codes: H04L 67/61 taking into account QoS or priority requirements
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]

Abstract

For a resource reservation in a distributed resource system, a tentative reservation request and a job reservation request are issued from a job scheduler to a resource management unit. The tentative reservation is valid for a short time period, and cannot coexist with another tentative reservation or the job reservation. In order to actually use resources, a job reservation must be issued after registration of the tentative reservation. If a tentative reservation request is received for a resource to which another tentative reservation request is already accepted, the tentative reservation request is stored in a wait queue, which is successful if the another tentative reservation is cancelled or failed due to the expiration of the validity time period.

Claims

1. A resource management unit for managing one or a plurality of resources, comprising:

a first section that, upon accepting a tentative reservation request designating at least one resource, changes a state of a free time period of said designated resource to a tentatively reserved time period based on said tentative reservation request, if the designated resource has no previous tentative reservation request and has the free time period, stores an expiration time of said tentatively reserved time period indicating a valid time, and information of an issuer of said tentative reservation request, wherein the valid time indicates a time period during which said tentative reservation request is valid, and the tentative reservation is added to a schedule storage unit;

a storage unit for storing said tentative reservation request in a wait queue corresponding to said designated resource, if the previous tentative reservation request designating the same resource and having previously tentatively reserved the free time period exists and the expiration time of the previously tentatively reserved time period is not expired; and

a second section that generates information of said tentatively reserved time period and a corresponding tentative reservation ID corresponding to said tentative reservation request in the wait queue;

a unit that discards the tentative reservation request if a job reservation request has not been received before the valid time of the tentative reservation expires or a tentative reservation cancel request has been received for cancelling the tentative reservation;

wherein a resource designated by the tentative reservation request may only be used by an issuer of the tentative reservation request if the job reservation request is issued after the tentative reservation within the valid time of the tentative reservation,

the cancel request is processed if the ID in the cancel request matches the tentative reservation ID,

the cancel request removes the tentative reservation in the wait queue or the schedule storage unit depending on where the tentative reservation is stored,

the unit further validates and takes out from the wait queue a next tentative reservation request that is made for the same resource as the removed tentative reservation and places it in the schedule storage unit, and

the job reservation request reserves a resource in advance for the execution of a specific job when the issuer of the job reservation request matches the issuer of the tentative reservation,

a job scheduler which creates an execution schedule that ignores the tentative reservation request remaining in the wait queue.

2. The resource management unit according to claim 1, wherein the tentative reservation request is accepted by the first section, the resource management unit further comprising:

a fourth section that, upon receiving the job reservation request designating said tentative reservation ID and requesting a reservation time period, changes said tentatively reserved time period to the reservation time period designated by said job reservation request to be actually reserved for an execution of the job, if said reservation time period designated by said job reservation request is included in said tentatively reserved time period corresponding to said designated tentative reservation ID and an issuer of said job reservation request matches with said issuer of said tentative reservation request.

3. The resource management unit according to claim 1, wherein the tentative reservation request is stored in the wait queue, the resource management unit further comprising:

a sixth section that reads out said next tentative reservation request stored in said wait queue, reserves said free time period to a newly tentatively reserved time period based on said next tentative reservation request, and stores information of an issuer of said next tentative reservation request; and

a seventh section that provides information of said newly tentatively reserved time period and a corresponding tentative reservation ID to the issuer of said next tentative reservation request.

4. A job scheduler communicating with at least one resource management unit for scheduling a job, said job scheduler comprising:

a computer which controls operation of;

a first member that issues a tentative reservation request designating resources of a plurality of resources to be used in a job, to the resource management unit managing said resources;

a second member that receives a notification in response to said tentative reservation request, the notification identifying a tentatively reserved state of said resources, wherein free time periods of the designated resources are tentatively reserved for the tentative reservation request and an expiration time of the tentatively reserved time periods is generated, which expiration time indicates a valid time wherein the valid time indicates a time period during which said tentative reservation request is valid;

wherein said tentative reservation request is stored in a schedule storage unit if the resources designated by the tentative reservation request has no previous tentative reservation request;

or else said tentative reservation request is stored in a wait queue, wherein the free time periods of the designated resources are not tentatively reserved;

a third member that assigns the job to at least one first resource among the resources, for which said tentatively reserved state is received, while excluding at least one second resource among said resources, for which the tentatively reserved state is received, to create a job schedule including an execution time period of said job for said at least one first resource, and stores the job schedule in a storage unit;

a fourth member that issues a job reservation request for said first resource, to said resource management unit; and

a fifth member that issues a tentative reservation cancel request for said at least one second resource, to said resource management unit,

wherein the tentative reservation request is discarded if a job reservation request has not been received before the valid time of the tentative reservation expires or the tentative reservation cancel request has been received for cancelling the tentative reservation,

a resource designated by the tentative reservation request may only be used by an issuer of the tentative reservation request if the job reservation request is issued after the tentative reservation within the valid time of the tentative reservation,

the cancel request is processed if the ID in the cancel request matches the tentative reservation ID,

the cancel request removes the tentative reservation in the wait queue or the schedule storage unit depending on where the tentative reservation is stored,

a next tentative reservation request that is made for the same resource as the removed tentative reservation is validated, taken out from the wait queue, and placed it in the schedule storage unit,

the job reservation request reserves a resource in advance for the execution of a specific job when the issuer of the job reservation request matches the issuer of the tentative reservation, and

the job scheduler creates an execution schedule that ignores the tentative reservation request remaining in the wait queue.

5. The job scheduler according to claim 4, further comprising:

a sixth member that, after receiving the notification of storage of said tentative reservation request in said wait queue from said resource management unit, controls said third member to create said job schedule either after a designated time interval elapsed since receiving said notification of the storage without a further notification, or after receiving another notification indicating that said tentative reservation request is obtained from said wait queue and a state of the designated resource is changed to said tentatively reserved state for the obtained tentative reservation request.

6. A distributed resource management system comprising:

a computer which controls operation of;

at least one resource management unit, which manages a plurality of resources, comprising;

a first section that, upon accepting a tentative reservation request designating at least one resource, changes a state of a free time period of said designated resource to a tentatively reserved time period based on said tentative reservation request, if the designated resource has no previous tentative reservation request and has the free time period, stores an expiration time of said tentatively reserved time period indicating a valid time, and information of an issuer of said tentative reservation request, wherein the valid time indicates a time period during which said tentative reservation request is valid, and the tentative reservation is added to a schedule storage unit;

a storage unit for storing said tentative reservation request in a wait queue corresponding to said designated resource, if the previous tentative reservation request designating the same resource and having previously tentatively reserved free time period exists and the expiration time of the previously tentatively reserved time period is not expired;

a second section that generates information of said tentatively reserved time period and a corresponding tentative reservation ID in response to said tentative reservation request in the wait queue;

a unit that discards the tentative reservation request if a job reservation request has not been received before the valid time of the tentative reservation expires or a tentative reservation cancel request has been received for cancelling the tentative reservation; and

a job scheduler communicating with said resource management unit, said job scheduler comprising;

a first member that issues the tentative reservation request designating resources of the plurality of resources to be used in a job, to said resource management unit;

a second member that receives information of a tentatively reserved state of said resources from said resource management unit, if the resources are tentatively reserved;

a third member that assigns the job to at least one first resource, for which said tentatively reserved state is received, and which is selected from said plurality of resources, while excluding at least one second resource, for which said tentatively reserved state is received, among said plurality of resources, to create a job schedule including an execution time period of said first resource, and stores the job schedule in a storage unit;

a fourth member that issues a job reservation request for said first resource, to said resource management unit; and

a fifth member that issues a tentative reservation cancel request for said second resource, to said resource management unit;

wherein a resource designated by the tentative reservation request may only be used by an issuer of the tentative reservation request if the job reservation request is issued after the tentative reservation within the valid time of the tentative reservation,

the cancel request is processed if the ID in the cancel request matches the tentative reservation ID,

the cancel request removes the tentative reservation in the wait queue or the schedule storage unit depending on where the tentative reservation is stored,

the unit further validates and takes out from the wait queue a next tentative reservation request that is made for the same resource as the removed tentative reservation and places it in the schedule storage unit,

the job reservation request reserves a resource in advance for the execution of a specific job when the issuer of the job reservation request matches the issuer of the tentative reservation, and

the job scheduler creates an execution schedule that ignores the tentative reservation request remaining in the wait queue.

7. A distributed resource management system comprising:

a computer which controls operation of;

at least one resource management unit that manages one or a plurality of resources; and

at least one job scheduler communicating with said at least one resource management unit, said job scheduler having a job reservation function for issuing a tentative reservation request and a job reservation request for the plurality of resources to be used in a job,

said resource management unit comprising;

a first section that receives said tentative reservation request and the job reservation request, issued by said job scheduler, wherein;

tentative reservation is a combinational operation of acquiring a reservation state of resources and tentatively reserving the resources and is performed by designating at least one resource and reserving a tentatively reserved time period within a free time period of the designated resource, and

job reservation includes an operation of reserving the resources in advance for an execution of the job and is performed via the job reservation request designating the at least one resource and reserving an execution time period in the resource;

a second section that, if the resource, for which said tentative reservation request is received, does not have another tentative reservation request and has the free time period, sets a tentatively reserved state for said resource and generates information of said tentatively reserved state including the tentatively reserved time period set within the free time period, in response to said tentative reservation request; and

the tentative reservation is added to a schedule storage unit;

a wait queue that stores said tentative reservation request if the resources designated by the tentative reservation request does have another tentative reservation request;

a third section that stores, in a storage unit, an expiration time of the tentatively reserved time period indicating a valid time, and information of said job scheduler having issued said tentative reservation request, wherein the valid time indicates a time period during which said tentative reservation request is valid;

a fourth section that accepts said job reservation request and changes the tentatively reserved time period to the execution time period specified by said job reservation request to be reserved for the execution of the job, if the specified execution time period is included in the tentatively reserved time period and the issuer of said job reservation request matches with the issuer of the tentative reservation request;

a fifth section that, when a start time specified by the job reservation request is reached, controls to allocate the resource for the execution of the job and, when an end time specified by said job reservation request is reached, controls to release allocation of the resource from the job; and

a unit that discards the tentative reservation request if the job reservation request has not been received before the valid time of the tentative reservation expires or a tentative reservation cancel request has been received for cancelling the tentative reservation;

wherein a resource designated by the tentative reservation request may only be used by an issuer of the tentative reservation request if the job reservation request is issued after the tentative reservation within the valid time of the tentative reservation,

the cancel request is processed if the ID in the cancel request matches the tentative reservation ID,

the cancel request removes the tentative reservation in the wait queue or the schedule storage unit depending on where the tentative reservation is stored,

the unit further validates and takes out from the wait queue a next tentative reservation request that is made for the same resource as the removed tentative reservation and places it in the schedule storage unit,

the job reservation request reserves a resource in advance for the execution of a specific job when the issuer of the job reservation request matches the issuer of the tentative reservation, and

the job scheduler creates an execution schedule that ignores the tentative reservation request remaining in the wait queue.

8. The distributed resource management system according to claim 7, wherein said resource management unit accepts cancel requests including the tentative reservation cancel request and a job cancel request issued corresponding to said tentative reservation request and the job reservation request issued by said job scheduler.

9. The distributed resource management system according to claim 7, further comprising at least one user terminal communicating with said job scheduler for inputting through said user terminal the job to said job scheduler, wherein said job scheduler comprises a first member that assigns said job input through said user terminal to the resources including at least one of:

a process of issuing the tentative reservation request to said resource management unit;

a process of creating an execution schedule of the job for the resources for which said tentative reservation was successful; and

a process of issuing the job reservation request according to said execution schedule to said resource management unit.

10. The distributed resource management system according to claim 7, wherein said resource management unit comprises:

the schedule storage unit that stores, for each resource managed by said resource management unit, information of said job designating said resources and the execution time period for which each resource is reserved;

a tentative-reservation-request storage unit that has a wait queue for each resource managed by said resource management unit, wherein a waiting tentative reservation request for said resource is stored in said wait queue;

a tentative-reservation-request receiving section that receives the tentative reservation request from said job scheduler and stores information of the tentative reservation request in said schedule storage unit or said tentative-reservation-request storage unit;

a job-reservation-request receiving section that receives the job reservation request from said job scheduler and stores information of the job reservation request in said schedule storage unit; and

a schedule management section that monitors the information of the job reservation request and the tentative reservation request stored in said schedule storage unit and performs at least one of allocating and releasing the resources and discarding of said tentative reservation request according to the information of said job reservation request and said tentative reservation request.

11. The distributed resource management system according to claim 10, wherein said resource management unit comprises:

a tentative-reservation-cancel-request receiving section that receives the tentative reservation cancel request from said job scheduler and discards information of a corresponding tentative reservation request from said schedule storage unit or said tentative-reservation-request storage unit; and

a job-cancel-request receiving section that receives a job reservation cancel request from said job scheduler and discards information of a corresponding job reservation request from said schedule storage unit and releases the resources allocated to the job.

12. The distributed resource management system according to claim 9, wherein said job scheduler comprises:

a waiting-job storage unit that temporarily stores information of the job input through said user terminal;

a schedule storage unit that stores information of the job for which the job reservation request is confirmed for each resource;

a job-execution-request receiving member that receives a job execution request from said user terminal and stores contents of said job execution request in said waiting-job storage unit; and

a job scheduling member that obtains the job stored in said waiting-job storage unit and assigns the job to the resources including issuing the tentative reservation request to said resource management unit, creating the job execution schedule, and issuing the job reservation request to said resource management unit.

13. The distributed resource management system according to claim 12, wherein said job scheduler comprises:

a job-cancel-request receiving member that, upon receiving a job cancel request from said user terminal, discards the job stored in said waiting-job storage unit or a corresponding job registered in said schedule storage unit, and issues a job reservation cancel request to said resource management unit.

14. The distributed resource management system according to claim 7, wherein said resource management unit further comprises:

a sixth section that assigns the resources for the execution of said job according to the job reservation request received from said job scheduler; and

a seventh section that, upon receiving a new tentative reservation request for previously tentatively reserved resources, stores said new tentative reservation request in a wait queue provided for each of the resources, wherein when a previous tentative reservation request is discarded due to a tentative reservation cancel request or a lapse of the expiration time indicating the validity of the time period tentatively reserved for the previous tentative reservation request, the new tentative reservation request directed to the same resource as the discarded tentative reservation request is obtained from the wait queue, and becomes a valid tentative reservation request,

an eighth section that, when the new tentative reservation request is obtained from said wait queue, issues a notification of said valid tentative reservation request to said job scheduler having issued said new tentative reservation request,

said job scheduler further comprising;

a first member that controls such that, when the new tentative reservation request issued by said job scheduler has entered said wait queue, creation of the job execution schedule waits until said new tentative reservation request becomes valid and then starts the creation of the job execution schedule.

15. The distributed resource management system according to claim 13, wherein said first member of said job scheduler further controls such that, if the new tentative reservation request does not become valid in a predetermined time interval, said job execution schedule is created while excepting the resource corresponding to the new tentative reservation request stored in said wait queue.

16. A method for use in a resource management unit that manages one or a plurality of resources, the method comprising:

accepting a tentative reservation request designating at least one resource if the designated resource has no previous tentative reservation request and has a free time period; and

adding the tentative reservation to a schedule storage unit;

changing a state of the free time period of said designated resource to a tentatively reserved time period based on said tentative reservation request;

storing an expiration time of said tentatively reserved time period indicating a valid time, and information of an issuer of said tentative reservation request, wherein the valid time indicates a time period during which said tentative reservation request is valid;

storing said tentative reservation request in a wait queue corresponding to said designated resource, if the tentative reservation request designating the same resource and having previously tentatively reserved the free time period exists and the expiration time of the previously tentatively reserved time period is not expired;

generating information of said tentatively reserved time period and a corresponding tentative reservation ID corresponding to said tentative reservation request; and

discarding the tentative reservation request if a job reservation request has not been received before the valid time of the tentative reservation expires or a tentative reservation cancel request has been received for cancelling the tentative reservation;

wherein a resource designated by the tentative reservation request may only be used by an issuer of the tentative reservation request if the job reservation request is issued after the tentative reservation within the valid time of the tentative reservation,

the cancel request is processed if the ID in the cancel request matches the tentative reservation ID,

the cancel request removes the tentative reservation in the wait queue or the schedule storage unit depending on where the tentative reservation is stored,

a next tentative reservation request that is made for the same resource as the removed tentative reservation is validated, taken out from the wait queue and placed in the schedule storage unit,

the job reservation request reserves a resource in advance for the execution of a specific job when the issuer of the job reservation request matches the issuer of the tentative reservation, and

an execution schedule that ignores the tentative reservation request remaining in the wait queue is created.

17. The method according to claim 16, wherein the tentative reservation request is accepted, the method further comprising:

receiving the job reservation request designating said tentative reservation ID and a reservation time period;

changing the tentatively reserved time period to said reservation time period designated by said job reservation request to be actually reserved for an execution of the job, if said reservation time period designated by said job reservation request is included in said tentatively reserved time period corresponding to said designated tentative reservation ID and an issuer of said job reservation request matches with said issuer of said tentative reservation request.

18. The method according to claim 16, further comprising:

canceling said previously tentatively reserved time period for which said expiration time has expired to revive said free time period;

reading out said next tentative reservation request stored in said wait queue,

changing the state of said revived free time period to a newly tentatively reserved time period based on said next tentative reservation request,

storing information of an issuer of said next tentative reservation request; and

providing information about said newly tentatively reserved time period and a corresponding tentative reservation ID to the issuer of said next tentative reservation request.

19. A method for use in a job scheduler, communicating with one or a plurality of resource management units, for scheduling a job, said method comprising:

issuing at least one tentative reservation request designating resources from a plurality of resources to be used in the job to at least one resource management unit managing said plurality of said resources;

receiving a notification in response to said tentative reservation request, the notification identifying a tentatively reserved state of said resources, wherein free time periods of the designated resources are tentatively reserved for the tentative reservation request and an expiration time of the tentatively reserved time periods is generated, which expiration time indicates a valid time, wherein the valid time indicates a time period during which said tentative reservation request is valid;

storing said tentative reservation request in a schedule storage unit if the resources designated by the tentative reservation request has no previous tentative reservation request;

or else storing said tentative reservation request in a wait queue, wherein the free time periods of the designated resources are not tentatively reserved;

assigning the job to at least one first resource among the plurality of resources, for which said tentatively reserved state is received, while excluding at least one second resource among said plurality of resources, for which said tentatively reserved state is received, to create a job schedule including an execution time period of said job for said at least one first resource;

issuing a job reservation request for said first resource, to said resource management unit;

issuing a tentative reservation cancel request for said at least one second resource, to said resource management unit; and

discarding the tentative reservation request if the job reservation request has not been received before the valid time of the tentative reservation expires or a tentative reservation cancel request has been received for cancelling the tentative reservation;

wherein a resource designated by the tentative reservation request may only be used by an issuer of the tentative reservation request if the job reservation request is issued after the tentative reservation within the valid time of the tentative reservation,

the cancel request is processed if the ID in the cancel request matches the tentative reservation ID,

the cancel request removes the tentative reservation in the wait queue or the schedule storage unit depending on where the tentative reservation is stored,

a next tentative reservation request that is made for the same resource as the removed tentative reservation is validated, taken out from the wait queue and placed in the schedule storage unit,

the job reservation request reserves a resource in advance for the execution of a specific job when the issuer of the job reservation request matches the issuer of the tentative reservation, and

an execution schedule that ignores the tentative reservation request remaining in the wait queue is created.

20. The method according to claim 19, further comprising:

creating, after receiving the notification of storage of said tentative reservation request in said wait queue from said resource management unit, said job schedule either after a designated time interval elapsed since receiving said notification without a further notification, or after receiving another notification indicating that said tentative reservation request is obtained from said wait queue and said tentatively reserved state is generated for the obtained tentative reservation request.

21. A method for use in a distributed resource management system including at least one resource management unit for managing at least one resource and at least one job scheduler communicating with said resource management unit having a job reservation function for reserving resources to be used in a job, said method comprising:

receiving a tentative reservation request and a job reservation request, issued by said job scheduler, wherein;

tentative reservation is a combinational operation of acquiring a reservation state of the resources and tentatively reserving the resources and is performed by designating at least one resource and reserving a tentatively reserved time period within a free time period of the designated resource, and

job reservation includes reserving the resources in advance for an execution of the job and is performed via the job reservation request designating the at least one resource and reserving an execution time period in the resource;

setting in said resource management unit a tentatively reserved state for said resource and reserving the tentatively reserved time period in response to said tentative reservation request, if the resource, for which said tentative reservation request is received, does not have another tentative reservation request and has the free time period;

adding the tentative reservation to a schedule storage unit;

storing the tentative reservation in a wait queue if the resource requested by the reservation does have another tentative reservation request;

storing in said resource management unit an expiration time of the tentatively reserved time period indicating a valid time, and information of said job scheduler having issued said tentative reservation request, wherein the valid time indicates a time period during which said tentative reservation request is valid;

accepting, by said resource management unit, said job reservation request and changing the tentatively reserved time period to the execution time period designated by said job reservation request to be reserved for an execution of the job, if the designated execution time period is included in the tentatively reserved time period and an issuer of said job reservation request matches with the issuer of the tentative reservation request; and

controlling to allocate the resource for the execution of the job when a start time designated by the job reservation request is reached, and to release allocation of the resource from the job when an end time designated by said job reservation request is reached; and

discarding the tentative reservation request if the job reservation request has not been received before the valid time of the tentative reservation expires or a tentative reservation cancel request has been received for cancelling the tentative reservation;

wherein a resource designated by the tentative reservation request may only be used by an issuer of the tentative reservation request if the job reservation request is issued after the tentative reservation within the valid time of the tentative reservation,

the cancel request is processed if the ID in the cancel request matches the tentative reservation ID,

the cancel request removes the tentative reservation in the wait queue or the schedule storage unit depending on where the tentative reservation is stored,

a next tentative reservation request that is made for the same resource as the removed tentative reservation is validated, taken out from the wait queue and placed in the schedule storage unit,

the job reservation request reserves a resource in advance for the execution of a specific job when the issuer of the job reservation request matches the issuer of the tentative reservation, and

an execution schedule that ignores the tentative reservation request remaining in the wait queue is created.

22. The method according to claim 21, wherein said resource management unit accepts cancel requests including the tentative reservation cancel request and a job cancel request issued corresponding to said tentative reservation request and the job reservation request issued by said job scheduler.

23. The method according to claim 21, further comprising assigning the job to the resources by said job scheduler, said job being input from a user terminal to said job scheduler, said assigning comprising:

issuing the tentative reservation request to said resource management unit;

creating an execution schedule of the job for the resources for which said tentative reservation was successful; and

issuing the job reservation request according to said execution schedule to said resource management unit.

24. The method according to claim 21, further comprising:

upon receiving the tentative reservation request in the resource management unit, storing information of a corresponding tentative reservation request in a schedule storage unit or in a wait queue provided in said resource management unit for each of said resources;

upon receiving said job reservation request in said resource management unit, storing information of a corresponding job reservation request in said schedule storage unit; and

monitoring the information of said job reservation request and said tentative reservation request, to perform one of allocating and releasing the resources, and discarding said tentative reservation request based on the information of said job reservation request and said tentative reservation request.

25. The method according to claim 21, further comprising at least one of:

receiving the tentative reservation cancel request in said resource management unit from said job scheduler to discard information of a corresponding tentative reservation request from said schedule storage unit or said wait queue; and

receiving a job reservation cancel request from said job scheduler to discard information of a corresponding job reservation request from said schedule storage unit and release resources allocated to the job.

26. The method according to claim 21, further comprising:

receiving a job execution request from said user terminal to store contents of a corresponding job in said job scheduler;

creating a job schedule corresponding to said job execution request in said job scheduler; and

assigning the job to the resources including issuing of the tentative reservation request to said resource management unit, creating a job execution schedule, and issuing the job reservation request to said resource management unit.

27. The method according to claim 26, further comprising:

upon receiving a job cancel request from said user terminal in the job scheduler, discarding in said job scheduler the job stored in a waiting job storage unit or a corresponding job registered in said schedule storage unit; and

issuing a job reservation cancel request from said job scheduler to said resource management unit.

28. The method according to claim 21, further comprising:

allocating the resources to an execution of said job according to the job reservation request received from said job scheduler;

upon receiving a new tentative reservation request for previously tentatively reserved resources by a previous tentative reservation request, storing said new tentative reservation request in a wait queue provided for each of the resources, wherein when the previous tentative reservation request is discarded due to a tentative reservation cancel request or a lapse of the expiration time of a tentatively reserved time period for the previous tentative reservation request, the new tentative reservation request directed to the same resource as the discarded tentative reservation request is obtained from the wait queue, and becomes a valid tentative reservation request,

upon the new tentative reservation request being obtained from said wait queue, issuing a notification of said valid tentative reservation request from said resource management unit to said job scheduler having issued said new tentative reservation request;

controlling said job scheduler such that, when the new tentative reservation request enters said wait queue, creation of a job execution schedule waits until said new tentative reservation request becomes the valid tentative reservation request and then starts the creation of the job execution schedule.

29. The method according to claim 28, further comprising:

ignoring the new tentative reservation request stored in said wait queue and proceeding to the creation of the job execution schedule, if the new tentative reservation request does not become valid in a predetermined time period.

30. A distributed resource management system comprising:

a resource management unit for managing resources;

a job scheduler communicating with said resource management unit to schedule a job to use said resources; and

a user terminal communicating with said job scheduler for issuing a first tentative reservation request prior to issuing a job reservation request for said resources, to said resource management unit;

said resource management unit comprising;

a first section that receives said first tentative reservation request from said job scheduler to set a state of the resource designated by said first tentative reservation request to a tentatively reserved state and tentatively reserve a free time period of the designated resource for the first tentative reservation, including setting an expiration time indicating a valid time of the tentatively reserved time for the first tentative reservation request, wherein the valid time indicates a time period during which said tentative reservation request is valid, and the first tentative reservation is added to a schedule storage unit; and

a second section that, when a second tentative reservation request is issued for the resource previously tentatively reserved for the first tentative reservation, stores the second tentative reservation request in a wait queue of a storage unit,

wherein said user terminal requests said job scheduler to execute the job, and

said job scheduler comprises a first member that, after issuing the first tentative reservation request to said resource management unit, determines the resources to which the job is assigned and issues the job reservation request to said resource management unit to reserve the resources for an execution of the job,

wherein said resource management unit further comprises;

a unit that discards the first tentative reservation request if a job reservation request has not been received before the valid time of the first tentative reservation expires or a tentative reservation cancel request has been received for cancelling the first tentative reservation,

wherein a resource designated by the first tentative reservation request may only be used by an issuer of the first tentative reservation request if the job reservation request is issued after the first tentative reservation within the valid time of the first tentative reservation,

the cancel request is processed if the ID in the cancel request matches the first tentative reservation ID,

the cancel request removes the first tentative reservation in the wait queue or the schedule storage unit depending on where the first tentative reservation is stored,

the unit further validates and takes out from the wait queue the second tentative reservation request that is made for the same resource as the removed first tentative reservation and places the second tentative reservation in the schedule storage unit,

the job reservation request reserves a resource in advance for the execution of a specific job when the issuer of the job reservation request matches the issuer of the tentative reservation, and

the job scheduler creates an execution schedule that ignores the second tentative reservation request remaining in the wait queue.

31. A distributed resource management method for a distributed resource system including at least one resource management unit that manages one or a plurality of resources, at least one job scheduler communicating with said at least one resource management unit and scheduling a job to use said resources, and at least one user terminal communicating with said job scheduler, said method comprising:

issuing a first tentative reservation request prior to issuing a job reservation request from said job scheduler for said resources to said resource management unit;

tentatively reserving free time periods of the resources for the first tentative reservation and storing an expiration time of the tentatively reserved time periods, which expiration time indicates a valid time indicating a time period during which the first tentative reservation request is valid;

adding the first tentative reservation to a schedule storage unit;

issuing a second tentative reservation request for previously tentatively reserved resource for the first tentative reservation, by said job scheduler;

storing said second tentative reservation request in a wait queue of said resource management unit; and

after issuing the first tentative reservation request to said resource management unit for said resources, determining the resources to which the job is assigned and issuing the job reservation request to said resource management unit to reserve the resources for an execution of the job,

wherein the first tentative reservation request is discarded if a job reservation request has not been received before the valid time of the first tentative reservation expires or a tentative reservation cancel request has been received for cancelling the first tentative reservation,

a resource designated by the first tentative reservation request may only be used by an issuer of the first tentative reservation request if the job reservation request is issued after the first tentative reservation within the valid time of the first tentative reservation,

the cancel request is processed if the ID in the cancel request matches the first tentative reservation ID,

the cancel request removes the first tentative reservation in the wait queue or the schedule storage unit depending on where the first tentative reservation is stored,

the second tentative reservation request that is made for the same resource as the removed first tentative reservation is validated, taken out from the wait queue, and placed in the schedule storage unit,

the job reservation request reserves a resource in advance for the execution of a specific job when the issuer of the job reservation request matches the issuer of the tentative reservation, and

the job scheduler creates an execution schedule that ignores the second tentative reservation request remaining in the wait queue.

32. A non-transitory computer readable medium storing a program, which when, executed by a computer constituting a resource management unit, which manages one or a plurality of resources, causes the computer to execute a method comprising:

accepting a tentative reservation request designating at least one resource, if the designated resource has no previous tentative reservation request and has at least one free time period to be tentatively reserved for the tentative reservation request;

changing a state of the at least one free time period of said designated resource to a tentatively reserved time period;

storing information of an expiration time of said tentatively reserved time period indicating a valid time, and information about an issuer of said tentative reservation request, wherein the valid time indicates a time period during which said tentative reservation request is valid;

adding the tentative reservation to a schedule storage unit;

storing said tentative reservation request in a wait queue for said designated resource, if the previous tentative reservation request designating the same resource and having the free time period tentatively reserved exists and the expiration time of said previously tentatively reserved time period is not expired;

providing information of said tentatively reserved time period and a corresponding tentative reservation ID corresponding to said tentative reservation request; and

discarding the tentative reservation request if the job reservation request has not been received before the valid time of the tentative reservation expires or a tentative reservation cancel request has been received for cancelling the tentative reservation;

wherein a resource designated by the tentative reservation request may only be used by an issuer of the tentative reservation request if the job reservation request is issued after the tentative reservation within the valid time of the tentative reservation,

the cancel request is processed if the ID in the cancel request matches the tentative reservation ID,

the cancel request removes the tentative reservation in the wait queue or the schedule storage unit depending on where the tentative reservation is stored,

a next tentative reservation request that is made for the same resource as the removed tentative reservation is validated, taken out from the wait queue, and placed in the schedule storage unit,

the job reservation request reserves a resource in advance for the execution of a specific job when the issuer of the job reservation request matches the issuer of the tentative reservation, and

an execution schedule that ignores the tentative reservation request remaining in the wait queue is created.

33. The medium according to claim 32, wherein the tentative reservation request is accepted and the method further comprises:

receiving the job reservation request designating said tentative reservation ID and a request time period,

changing said tentatively reserved time period to the request time period designated by said job reservation request to be reserved for an execution of the job, if said request time period is included in said tentatively reserved time period corresponding to said tentative reservation ID and an issuer of said job reservation request matches with the issuer of said tentative reservation request.

34. The medium according to claim 32, wherein the tentative reservation request is stored in the wait queue and the method further comprises:

canceling said previously tentatively reserved time period for which said expiration time has expired to revive said free time period;

obtaining the next tentative reservation request from said wait queue;

changing a state of said revived free time period to a newly tentatively reserved time period based on said next tentative reservation request;

storing information identifying the issuer of said next tentative reservation request; and

providing a notification of said newly tentatively reserved time period and a tentative reservation ID corresponding to said next tentative reservation request to the issuer thereof.

35. A non-transitory computer readable medium storing a program, which, when executed by a computer constituting a job scheduler, that is communicating with a resource management unit, which manages one or a plurality of resources, causes the computer to execute a method comprising:

issuing a tentative reservation request for the resources to be used by a job, to said resource management unit;

tentatively reserving the resources including tentatively reserving free time periods of the resources, based on the tentative reservation request;

setting an expiration time indicating a valid time of the tentatively reserved time periods, wherein the valid time indicates a time period during which said tentative reservation request is valid;

storing said tentative reservation request in a wait queue of said resource management unit if the resource requested by the tentative reservation request have another tentative request;

adding the tentative reservation to a schedule storage unit if the resource requested by the tentative reservation request does not have another tentative resource request;

selecting the resources to which said job is assigned from the resources that are tentatively reserved by said resource management unit and reserving an execution time period, for an execution of the job, within the tentatively reserved time periods for which the expiration time is not expired;

issuing a job reservation request for the resources selected by said selecting to said resource management unit;

issuing a tentative reservation cancel request for at least one of the resources tentatively reserved by said tentative reservation request, to said resource management unit; and

discarding the tentative reservation request if the job reservation request has not been received before the valid time of the tentative reservation expires or the tentative reservation cancel request has been received for cancelling the tentative reservation;

wherein a resource designated by the tentative reservation request may only be used by an issuer of the tentative reservation request if the job reservation request is issued after the tentative reservation within the valid time of the tentative reservation,

the cancel request is processed if the ID in the cancel request matches the tentative reservation ID,

the cancel request removes the tentative reservation in the wait queue or the schedule storage unit depending on where the tentative reservation is stored,

a next tentative reservation request that is made for the same resource as the removed tentative reservation is validated, taken out from the wait queue, and placed in the schedule storage unit,

the job reservation request reserves a resource in advance for the execution of a specific job when the issuer of the job reservation request matches the issuer of the tentative reservation, and

an execution schedule that ignores the tentative reservation request remaining in the wait queue is created.

36. The medium according to claim 35, wherein the method further comprises:

controlling to proceed to said selecting after a predetermined time period has elapsed or a notification of said tentative reservation request having been obtained from said wait queue has arrived.