System and method of providing a self-optimizing reservation in space of compute resources

A system and method of dynamically controlling a reservation of compute resources within a compute environment is disclosed. The method aspect of the invention comprises receiving a request from a requestor for a reservation of resources within the compute environment, reserving a first group of resources, evaluating resources within the compute environment to determine if a more efficient use of the compute environment is available and if a more efficient use of the compute environment is available, then canceling the reservation for the first group of resources and reserving a second group of resources of the compute environment according to the evaluation.

RELATED APPLICATIONS

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to reservations in a cluster or more specifically to a system and method of providing a self-optimizing reservation in space of compute resources.

The present invention relates to a system and method of allocation resources in the context of a grid or cluster of computers. Grid computing may be defined as coordinated resource sharing and problem solving in dynamic, multi-institutional collaborations. Many computing projects require much more computational power and resources than a single computer may provided. Networked computers with peripheral resources such as printers, scanners, I/O devices, storage disks, scientific devices and instruments, etc. may need to be coordinated and utilized to complete a task.

Grid/cluster resource management generally describes the process of identifying requirements, matching resources to application, allocating those resources, and scheduling and monitoring grid resources over time in order to run grid applications as efficiently as possible. Each project will utilized a different set of resources and thus is typically unique. In addition to the challenge of allocating resources for a particular job, grid administrators also have difficulty obtaining a clear understanding of the resources available, the current status of the grid and available resources, and real-time competing needs of various users. One aspect of this process is the ability to reserve resources for a job. A cluster manager will seek to reserve a set of resources to enable the cluster to process a job at a promised quality of service.

General background information on clusters and grids may be found in several publications. See, e.g.,Grid Resource Management, State of the Art and Future Trends, Jarek Nabrzyski, Jennifer M. Schopf, and Jan Weglarz, Kluwer Academic Publishers, 2004; andBeowulf Cluster Computing with Linux, edited by William Gropp, Ewing Lusk, and Thomas Sterling, Massachusetts Institute of Technology, 2003.

It is generally understood herein that the terms grid and cluster are interchangeable in that there is no specific definition of either. In general, a grid will comprise a plurality of clusters as will be shown inFIG. 1A. Several general challenges exist when attempting to maximize resources in a grid. First, there are typically multiple layers of grid and cluster schedulers. A grid100generally comprises a group of clusters or a group of networked computers. The definition of a grid is very flexible and may mean a number of different configurations of computers. The introduction here is meant to be general given the variety of configurations that are possible. A grid scheduler102communicates with a plurality of cluster schedulers104A,104B and104C. Each of these cluster schedulers communicates with a respective resource manager106A,106B or106C. Each resource manager communicates with a respective series of compute resources shown as nodes108A,108B,108C in cluster110, nodes108D,108E,108F in cluster112and nodes108G,108H,108I in cluster114.

Local schedulers (which may refer to either the cluster schedulers104or the resource managers106) are closer to the specific resource108and may not allow grid schedulers102direct access to the resources. Examples of compute resources include data storage devices such as hard drives and computers processors. The grid level scheduler102typically does not own or control the actual resources. Therefore, jobs are submitted from the high level grid-scheduler102to a local set of resources with no more permissions that then user would have. This reduces efficiencies and can render the reservation process more difficult.

The heterogeneous nature of the shared resources also causes a reduction in efficiency. Without dedicated access to a resource, the grid level scheduler102is challenged with the high degree of variance and unpredictability in the capacity of the resources available for use. Most resources are shared among users and projects and each project varies from the other. The performance goads for projects differ. Grid resources are used to improve performance of an application but the resource owners and users have different performance goals from optimizing the performance for a single application to getting the best system throughput or minimizing response time. Local policies may also play a role in performance.

Within a given cluster, there is only a concept of resource management in space. An administrator can partition a cluster and identify a set of resources to be dedicated to a particular purpose and another set of resources can be dedicated to another purpose. In this regard, the resources are reserved in advance to process the job. There is currently no ability to identify a set of resources over a time frame for a purpose. By being constrained in space, the nodes108A,108B,108C, if they need maintenance or for administrators to perform work or provisioning on the nodes, have to be taken out of the system, fragmented permanently or partitioned permanently for special purposes or policies. If the administrator wants to dedicate them to particular users, organizations or groups, the prior art method of resource management in space causes too much management overhead requiring a constant adjustment the configuration of the cluster environment and also losses in efficiency with the fragmentation associated with meeting particular policies.

To manage the jobs submissions, a cluster scheduler will employ reservations to insure that jobs will have the resources necessary for processing.FIG. 1Billustrates a cluster/node diagram for a cluster124with nodes120. Time is along the X axis. An access control list114(ACL) to the cluster is static, meaning that the ACL is based on the credentials of the person, groups, account, class or quality of service making the request or job submission to the cluster. The ACL114determines what jobs get assigned to the cluster110via a reservation112shown as spanning into two nodes of the cluster. Either the job can be allocated to the cluster or it can't and the decision is determined based on who submits the job at submission time. The deficiency with this approach is that there are situations in which organizations would like to make resources available but only in such a way as to balance or meet certain performance goals. Particularly, groups may want to establish a constant expansion factor and make that available to all users or they may want to make a certain subset of users that are key people in an organization and want to give them special services but only when their response time drops below a certain threshold. Given the prior art model, companies are unable to have the flexibility over their cluster resources.

To improve the management of cluster resources, what is needed in the art is a method for a scheduler, a cluster scheduler or cluster workload management system to manage resources in a dimensional addition to space. Furthermore, given the complexity of the cluster environment, what is needed is more power and flexibility in the reservations process.

SUMMARY OF THE INVENTION

The invention herein relates to systems, methods and computer-readable media for optimizing the resources used in a computer environment such as a cluster or a grid. The method aspect of the invention dynamically controls a reservation of compute resources by receiving a request from a requestor for a reservation of resources within the compute environment, reserving a first group of resources and evaluating resources within the compute environment to determine if a more efficient use of the compute environment is available. If a more efficient use of the compute environment is available, then the method comprises canceling the reservation for the first group of resources and reserving a second group of resources of the compute environment according to the evaluation. The method may also include modifying a current reservation of resources to improve the efficient use of the environment.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to resource reservations in the context of a cluster environment. The cluster may be operated by a hosting facility, hosting center, a virtual hosting center, data center, grid, cluster and/or utility-based computing environments.

Every reservation consists of three major components a set of resources, a timeframe, and an access control list (ACL). Additionally, a reservation may also have a number of optional attributes controlling its behavior and interaction with other aspects of scheduling. A reservation's ACL specifies which jobs can use the reservation. Only jobs which meet one or more of a reservation's access criteria are allowed to use the reserved resources during the reservation timeframe. The reservation access criteria comprises, in one example, at least following: users, groups, accounts, classes, quality of service (QOS) and job duration. A job may be any venue or end of consumption of resource for any broad purpose, whether it be for a batch system, direct volume access or other service provisioning.

A workload manager, or scheduler, will govern access to the compute environment by receiving requests for reservations of resources and creating reservations for processing jobs. A workload manager functions by manipulating five primary, elementary objects. These are jobs, nodes, reservations, QOS structures, and policies. In addition to these, multiple minor elementary objects and composite objects are also utilized. These objects are also defined in a scheduling dictionary.

A workload manager may operate on a single computing device or multiple computing devices to manage the workload of a compute environment. The “system” embodiment of the invention may comprise a computing device that includes the necessary hardware and software components to enable a workload manager or a software module performing the steps of the invention. Such a computing device may include such known hardware elements at one or more central processors, random access memory (RAM), read-only memory (ROM), storage devices such as hard disks, communication means such as a modem or a card to enable networking with other computing devices, a bus that provides data transmission between various hardware components, a keyboard, a display, an operating system and so forth. There is no restriction that the particular system embodiment of the invention have any specific hardware components and any known or future developed hardware configurations are contemplated as within the scope of the invention when the computing device operates as is claimed.

An ACL for the reservation may have a dynamic aspect instead of simply being based on who the requester is. The ACL decision making process is based at least in part on the current level of service or response time that is being delivered to the requester. To illustrate the operation of the ACL, assume that a user submits a job and that the ACL reports that the only job that can access these resources are those that have a queue time that currently exceeds two hours. If the job has sat in the queue for two hours it will then access the additional resources to prevent the queue time for the user from increasing significantly beyond this time frame. The decision to allocate these additional resources can be keyed off of utilization of an expansion factor and other performance metrics of the job.

Whether or not an ACL is satisfied is typically and preferably determined the scheduler104A. However, there is no restriction in the principle of the invention regarding where or on what node in the network the process of making these allocation of resource decisions occurs. The scheduler104A is able to monitor all aspects of the request by looking at the current job inside the queue and how long it has sat there and what the response time target is and the scheduler itself determines whether all requirements of the ACL are satisfied. If requirements are satisfied, it releases the resources that are available to the job. A job that is located in the queue and the scheduler communicating with the scheduler104A. If resources are allocated, the job is taken from the queue and inserted into the reservation in the cluster.

An example benefit of this model is that it makes it significantly easier for a site to balance or provide guaranteed levels of service or constant levels of service for key players or the general populace. By setting aside certain resources and only making them available to the jobs which threaten to violate their quality of service targets it increases the probability of satisfying it.

The disclosure now continues to discuss reservations further. An advance reservations is the mechanism by which the present invention guarantees the availability of a set of resources at a particular time. With an advanced reservation a site now has an ability to actually specify how the scheduler should manage resources in both space and time. Every reservation consists of three major components, a list or resources, a timeframe (a start and an end time during which it is active), and an access control list (ACL). These elements are subject to a set of rules. The ACL acts as a doorway determining who or what can actually utilize the resources of the cluster. It is the job of the cluster scheduler to make certain that the ACL is not violated during the reservation's lifetime (i.e., its timeframe) on the resources listed. The ACL governs access by the various users to the resources. The ACL does this by determining which of the jobs, various groups, accounts, jobs with special service levels, jobs with requests for specific resource types or attributes and many different aspects of requests can actually come in and utilize the resources. With the ability to say that these resources are reserved, the scheduler can then enforce true guarantees and can enforce policies and enable dynamic administrative tasks to occur. The system greatly increases in efficiency because there is no need to partition the resources as was previously necessary and the administrative overhead is reduced it terms of staff time because things can be automated and scheduled ahead of time and reserved.

As an example of a reservation, a reservation may specify that node002 is reserved for user John Doe on Friday. The scheduler will thus be constrained to make certain that only John Doe's jobs can use node002 at any time on Friday. Advance reservation technology enables many features including backfill, deadline based scheduling, QOS support, and meta scheduling.

There are several reservation concepts that will be introduced as aspects of the invention. These included dynamic reservations, co-allocating reservation resources of different types, reservations that self-optimize in time, reservations that self-optimization in space, reservations rollbacks and reservations masks. Each of these will be introduced and explained.

Dynamic reservations are reservations that are able to be modified once they are created.FIG. 2Aillustrates a dynamic reservation. Attributes of a reservation may change based on a feedback mechanism that adds intelligence as to ideal characteristics of the reservation and how it should be applied as the context of its environment or an entities needs change. One example of a dynamic reservation is a reservation that provides for a guarantee of resources for a project unless that project is not using the resources it has been given. A job associated with a reservation begins in a cluster environment (202). At a given portion of time into processing the job on compute resources, the system receives compute resource usage feedback relative to the job (204). For example, a dynamic reservation policy may apply which says that if the project does not use more than 25% of what it is guaranteed by the time that 50% of its time has expired, then, based on the feedback, the system dynamically modifies the reservation of resources to more closely match the job (206). In other words, the reservation dynamically adjust itself to reserve X % fewer resources for this project, thus freeing up unused resource for others to use.

Another dynamic reservation may perform the following step: if usage of resources provided by a reservation is above 90% with fewer than 10 minutes left in the reservation then the reservation will attempt to add 10% more time to the end of the reservation to help ensure the project is able to complete. In summary, it is the ability for a reservation to receive manual or automatic feedback to an existing reservation in order to have it more accurately match any given needs, whether those be of the submitting entity, the community of users, administrators, etc. The dynamic reservation improves the state of the art by allowing the ACL to the reservation to have a dynamic aspect instead of simply being based on who the requestor is. The reservation can be based on a current level of service or response time being delivered to the requestor.

Another example of a dynamic reservation is consider a user submitting a job and the reservation may need an ACL that requires that the only job that can access these resources are those that have a queue time that is currently exceeded two hours. If the job has sat in the queue for two hours it will the access the additional resources to prevent the queue time for the user from increasing significantly beyond this time frame. You can also key the dynamic reservation off of utilization, off of an expansion factor and other performance metrics of the job.

The ACL and scheduler are able to monitor all aspects of the request by looking at the current job inside the queue and how long it has sat there and what the response time target is. It is preferable, although not required, that the scheduler itself determines whether all requirements of the ACL are satisfied. If the requirements are satisfied, the scheduler released the resources that are available to the job.

The benefits of this model is it makes it significantly easier for a site to balance or provide guaranteed levels of service or constant levels of service for key players or the general populace. By setting aside certain resources and only making them available to the jobs which threaten to violate their quality of service targets it increases the probability of satisfying it.

FIG. 2Billustrates another aspect of the invention, which is the dynamic, self-optimizing reservation in space. This reservation seeks to improve the efficient use of the compute resources. This is in contrast to a reservation that may self-optimize to improve a response time for jobs submitted by the reservation requestor. As shown inFIG. 2B, the method comprises receiving a request from a requestor for a reservation of resources within the compute environment to determine if a more efficient use of the compute environment is available (214) and determining if a more efficient use of the compute environment is available (216). If a more efficient use of the compute environment is available, then the method comprises modifying the reservation for the first group of resources to reserve a second group of resources of the compute environment (218). The modification may comprise canceling the first reservation and making a second reservation of a second group of resources that is more efficient or the modification may comprise maintaining the current reservation but changing the resources reserved.

The reservation may be identified as self-optimizing either by the system, by a policy or by the requestor. The self-optimizing classification may further mean that it is self-optimizing in terms of the efficiency of the compute resources or in some other terms such as improved time to process jobs.

The compute environment is one of a cluster environment, grid environment or some other plurality of computing devices, such as computer servers that are networked together. The reservation for the first group of resources and the reservation for the second group of resources may overlap in terms of time or resources (space).

The request for resources may include a required criteria and a preferred criteria. The criteria may based cost-based (least expensive) time based (fastest processing time) and so forth. It is preferred that the reservation of the first group of resources meets the required criteria and the evaluation of resources within the cluster environment determines if use of the resources in the compute environment can be improved further comprises evaluating resources to determine if at least one of the preferred criteria can be met by modifying the reservation of resources.

The determination of whether the use of the compute environment can be improved can include a comparison of a cost of canceling the first group of resources and reserving the second group of resources with the improved used of the compute environment gained from meeting at least one of the preferred criteria. In this case, if the cost of canceling the reservation of first group of resources and reserving the second group of resources is greater than improved usage of the compute environment gained by meeting at least one of the preferred criteria, then the reservation of first group of resources is not cancelled. A threshold value may be established to determine when it is more efficient to cancel the reservation of first group of resources and reserve the second group of resources to meet at least one of the preferred criteria.

Although the above description may contain specific details, they should not be construed as limiting the claims in any way. Other configurations of the described embodiments of the invention are part of the scope of this invention. Accordingly, the appended claims and their legal equivalents should only define the invention, rather than any specific examples given.