Patent Publication Number: US-7720907-B2

Title: Supervisor partitioning of client resources

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application is a continuation of U.S. patent application Ser. No. 10/986,577, filed Nov. 12, 2004, the disclosure of which is incorporated by reference herein in its entirety. 

   BACKGROUND 
   The present invention relates generally to managing resources within a communications environment, and, more particularly, to a method and system for supervisor partitioning of resources across a communications medium. 
   In one embodiment, a communications environment includes a plurality of client nodes coupled to one or more nodes via a communications medium. One example of such as communications medium is the InfiniBand™ medium, which is described in further detail in “InfiniBand Architecture Specification Volume  1 ,” Release 1.2, October, 2004, available from the InfiniBand Trade Association at 5440 SW Westgate Drive, Suite 217, Portland, Oreg., 97221, or online at www.Infinibandta.org, which is hereby incorporated herein by reference in its entirety. InfiniBand is a trademark of the InfiniBand Trade Association. 
   The InfiniBand transport enables a set of interconnected nodes, referred to as a subnet, to communicate with one another. It also provides a partitioning scheme that allows a subnet to be logically subdivided into sets of nodes, referred to as partitions. A partition includes one or more nodes, acting as either clients or server nodes. A node, such as a server node, can be included in more than one partition. The members of a partition communicate with one another, but are unable to access partitions in which they are not members. 
   Within an InfiniBand™ (IB) fabric, resource-provider nodes that may be shared by various client nodes are partitioned by a Subnet Manager such that each client node is allowed to reach and therefore use all the resources at the shared node. Thus, when a node (e.g., a server node) is included in multiple partitions, all of the resources of that node are accessible by all of the partitions that include that node. When a resource provider node receives a request from a client node, it provides access to all of the resources that the client node is allowed to use regardless of the application within the client node from which the request came. However, this accessibility is not adequate in many cases from either a security or performance standpoint when there is a need to restrict the resources that each application can access as a subset of all resources allocated to the node. Thus, a need exists for a capability that restricts the resources that each application on a given client node is allowed to use. More particularly, a need exists for such a capability in which the resource allocations of a client node may be dynamically changed by the hypervisor or supervisor. Providing the hypervisor or supervisor with this capability will enable resource balancing to occur at system speeds without the need for human interaction, such that system operations may continue uninterrupted. 
   SUMMARY 
   In an exemplary embodiment, a system for supervisor partitioning of client resources in a subnet communications environment includes a plurality of client nodes, each receiving an allocated set of resources determined by a central authority, wherein the central authority assigns resources to a supervisor key associated with each supervisor of the plurality of client nodes; means for partitioning, at each of the plurality of client nodes, the allocated set of resources among one or more applications associated with each of the plurality of client nodes using a local supervisor associated therewith, the local supervisor capable of allocating subsets of the resources allocated to the client node among each of its client applications, wherein the partitioning further comprises each supervisor associating one or more resource keys with one or more resources allocated to the corresponding client node, and assigning the one or more resource keys to the one or more applications; wherein the supervisor keys are configured so as to prevent a given supervisor from partitioning resources not allocated to the client node associated therewith; and wherein, following the partitioning, communication packets are issued from the one or more applications to a resource provider node without inspection by the corresponding supervisor. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring to the exemplary drawings wherein like elements are numbered alike in the several Figures: 
       FIG. 1  is a schematic block diagram of an exemplary communications environment (e.g., IB subnet) suitable for use in accordance with an embodiment of the invention; 
       FIG. 2  is a schematic block diagram of a configuration sequence for the supervisor partitioning of the exemplary communications environment of  FIG. 1 ; 
       FIGS. 3(   a ) through  3 ( c ) are schematic block diagrams that illustrate further supervisor partitioning capabilities of the present invention embodiments; and 
       FIG. 4  is an exemplary computing system in which the supervisor partitioning scheme may be implemented. 
   

   DETAILED DESCRIPTION 
   Disclosed herein is a method and system for supervisor partitioning of client resources in a communications environment. Briefly stated, a supervisor (or hypervisor) within a client node may configure a resource provider node such that the resource provider node will restrict the resources that each application on the client node is allowed to use. Because it is the supervisor program that actually changes the resource allocations of its client applications dynamically (and thus obviating the need for human interaction), system operations can continue uninterrupted. 
   A mechanism is defined herein that allows a supervisor (or a hypervisor) within the client node to control the resources on a resource-provider node that each of its client applications is allowed to use. In this manner, the supervisor can dynamically subdivide the resource provider node&#39;s resources and allocate a subset of those resources to each of its client applications. This in turn enables the supervisor to manage the I/O, computing demands and resource authorizations of each of its client applications in an enforceable and more efficient manner than was previously possible, and further shifts the burden of assigning client resources from the system administrator to the supervisor (or hypervisor). 
   In order to enable a supervisor (or hypervisor) to limit the resources that each of its client applications can use, a “resource key” is defined. In an exemplary embodiment, such resource keys are sequences of digits that can be arbitrarily long, thereby being unguessable. Supervisors are able to associate each resource key with a subset of the available resources within a resource-provider node, and also to provide that resource key(s) to each of their client applications. The manner in which this is carried out enables the supervisor to enforceably manage the resources accessed by each of its clients. Although the supervisor can allocate subsets of the resources available to the node among each of its client applications, the resource-provider does not allow a supervisor to allocate more resources than were originally assigned to the supervisor&#39;s node by a network administrator device manager during configuration. 
   After the supervisor creates the associations between client applications, resource keys, and resources at a resource-provider node, the supervisor passes the resource key to the client application. Having done this, the supervisor does not then need to subsequently inspect each request packet issued by its client applications to resource provider nodes in order to ensure that the application is only accessing authorized resources. This inspection is unnecessary since the resource-provider nodes are directly able to determine the allowed resources, based on the resource key contained in the request packet from the client application. 
   Referring now to  FIG. 1 , there is shown a schematic block diagram of an exemplary communications environment  100  (e.g., subnet) suitable for use in accordance with an embodiment of the invention. In the example of  FIG. 1 , three client nodes  102  are illustrated: Client Node A, Client Node B, and Client Node C. Each client node  102  in turn includes a supervisor (i.e., a local authority), designated as Supervisor A, Supervisor B, and Supervisor C, respectively. A resource-provider node  104  (e.g., an InfiniBand “IB” I/O unit, or IOU) is shared among the three client nodes  102  in the subnet (i.e., Client Node A, Client Node B, and Client Node C). Furthermore, each of the client nodes A, B, and C has a corresponding supervisor key  106   a ,  106   b ,  106   c , designated as Supervisor Key A, Supervisor Key B, and Supervisor Key C, respectively. 
   During initialization, a manager node (i.e., a centralized authority) such as an IB Device Manager (not shown  FIG. 1 ) associates a subset of the resources  108  of the resource-provider node  104  with each supervisor key. In the exemplary embodiment depicted, the individual resources  108  are designated R 1  through  10 . As is further shown in  FIG. 1 , resources R 1 , R 5 , and R 7  are associated with Supervisor Key A. Resources R 2 , R 3 , and R 4  are associated with Supervisor Key B, while resources R 6 , R 8 , R 9 , and R 10  are associated with Supervisor Key C. In accordance with an embodiment of the invention, during initialization, a plurality of resource keys  110  are associated with each supervisor key  106 , wherein a specific resource key corresponds to an application  112  of a given client node. 
   For example, Resource Keys A 1  and A 2  are associated with Supervisor Key A, Resource Keys B 1  and B 2  are associated with Supervisor Key B, and Resource Keys C 1 , C 2  and C 3  are associated with Supervisor Key C. During an initialization process, specific application resources are generally not associated with resource keys during initialization. Rather, this association between a resource key and a specific application is implemented after initialization by the respective supervisors of each client node, as explained hereinafter. 
   Referring now to  FIG. 2 , there is shown a schematic block diagram of configuration sequence  200  for the exemplary communications environment  100  of  FIG. 1 . As is shown, an IB device manager/network administrator  202  communicates a sequence of three (for example) messages  204 ,  206 ,  208  to the resource-provider node  104 . The first message  204  informs the resource-provider node  104  to assign resources R 1 , R 5  and R 7  to Supervisor Key A and assigns the number and value of each resource key  110 . The second message  206  informs the resource-provider node  104  to assign resources R 2 , R 3  and R 4  to Supervisor Key B and assigns the number and value of each resource key  110 , and the third message  208  informs the resource-provider node  104  to assign resources R 6 , R 8 , R 9  and R 10  to Supervisor Key C and assigns the number and value of each resource key  110 . 
   As a result, the resource provider node  104  in turn assigns ( 210 ) resources R 1 , R 5  and R 7  to Supervisor Key A, assigns ( 212 ) resources R 2 , R 3  and R 4  to Supervisor Key B, and assigns ( 214 ) resources R 6 , R 8  and R 9  to Supervisor Key C. Alternatively, the device manager/network administrator  202  could request the resource provider node  104  initiate the key generation process and return the generated keys back to the device manager/network administrator  202 . 
   As indicated previously, however, it is the role of the client node supervisor (or hypervisor) to specifically allocate the assigned node resources to the particular applications associated therewith. Accordingly,  FIG. 2  further illustrates a series of communications from each client node supervisor back to the resource-provider node  104  that set forth the assignment of specific resources to specific client applications. In the example depicted, Supervisor Node A sends a configuration packet  215  containing a first message  216  that assigns Resource Key A 1  to resources R 1  and R 7 , and a second message  218  that assigns Resource Key A 2  to resource R 5 . Similarly, Supervisor Node B sends a configuration packet  219  containing a first message  220  that assigns Resource Key B 1  to resources R 2  and R 4 , and a second message  222  that assigns Resource Key B 2  to resource R 3 . Supervisor Node C sends a configuration packet  223  containing a first message  224  that assigns Resource Key C 1  to resource R 10 , a second message  226  that assigns Resource Key C 2  to resources R 8  and R 9 , and a third message  228  that assigns Resource Key C 3  to resource R 8 . Thus, in the example depicted, resource R 8  of Client Node C is initially allocated to two applications (C 2 , C 3 ), while resource R 6  is initially unallocated. 
   In sending the configuration packets to the resource-provider node  104 , each client node supervisor includes its corresponding supervisor key, thus identifying the client node. In order to prevent the supervisor of node B or node C from modifying the resources allocated to Supervisor Key A, the resource-provider node  104  only allows a request that contains Supervisor key A to allocate resources to Resource Keys A 1  and A 2 . The same is true for Supervisors B and C. Once a supervisor has associated a subset of the available resources to each of its client applications, a resource key is then passed from the supervisor (or hypervisor) to each of the client applications. As a further result, the resource provider node  104  internally assigns ( 230 ) R 1  and R 7  to Resource Key A 1 ; assigns ( 232 ) R 2  and R 4  to Resource Key B 1 ; assigns ( 234 ) R 8  and R 9  to Resource Key C 2 ; assigns ( 236 ) R 8  to Resource Key C 3 ; assigns ( 238 ) R 10  to Resource Key C 1 ; assigns ( 240 ) R 3  to Resource Key B 2 ; and assigns ( 242 ) R 5  to Resource Key A 2 . 
   Once these initial configuration steps are implemented, the client applications may thereafter make connection requests directly to the resource-provider node  104  without supervisor intervention. To facilitate this, the client application sends a request (such as a connection request, for example) directly to the resource-provider node  104 . The request contains the client application&#39;s resource key, which was initially provided to the client by its supervisor. Upon receipt of the request, the resource-provider node  104  provides query and access capability only to resources allowed by the resource key in the message. 
   A significant advantage of the above described methodology is that the request from the client application may be made (after initial connection with the resource provider node) without interaction with the supervisor of the client node. Rather, checking and verification of packets takes place in the resource-provider  104  by means of software or hardware (e.g., standard IB agents) on the resource-provider  104  such as, for example, the communication manager agent or the Device Manager Agent. Because the resource-provider  104  is able to determine whether use of the requested resource is allowed, system performance is not impacted due to supervisor intervention. Furthermore, when the determination of the allowed resources is carried out during connection establishment, there is no need for further verification of any subsequent request packets passed between the two end nodes on a given connection. 
   Finally,  FIGS. 3(   a ) through  3 ( c ) are schematic block diagrams that illustrate further supervisor partitioning capabilities of the present invention embodiments. In  FIG. 3(   a ), the administrator has partitioned the resource-provider node for each of the client nodes (Client Node A, Client Node B, Client Node C) as shown before. Resource R 6  is assigned to Node C, but is not initially allocated to any of its client applications by Node C. Thus, none of the resource keys C 1 , C 3 , C 3  of Client Node C are associated with R 6 . However, as shown in  FIG. 3(   b ), the supervisor of Client Node C engages a new client application C 4 , and further assigns previously unassigned resource R 6  to application C 4  without administration assistance. This is permitted, since R 6  was initially assigned to Client Node C and since a supervisor may assign, reassign or prevent one or more client applications from accessing any resource assigned to it by the administrator. 
     FIG. 3(   c ) demonstrates the capability of supervisors on separate nodes to collaborate in a fault tolerant design using the present methodology. In this configuration, resource R 3  is shared by both Client Node A and Client Node B (due to initial allocation of R 3  to both client nodes by the administrator). Furthermore, resource R 3  is allocated to application A 2  by the supervisor of Client Node A, and is also allocated to application B 2  by the supervisor of Client Node B. If application B 2  is the designated backup or standby for application A 2 , and either Node A or application A 2  fails, then Application B 2  has access to resource R 3  and can take over at machine speeds without the need for the administrator involvement. 
     FIG. 4  is a block diagram of an embodiment of an exemplary computer system  400  in which the above described supervisor partitioning scheme may be implemented. The computer system  400  illustrated in  FIG. 4  is intended to represent a broad range of computer systems, and thus alternative computer systems may include more, fewer and/or different components. 
   As shown in  FIG. 4 , the computer system  400  includes a bus  402  or other communication device to communicate information, as well as a processor  404  coupled to the bus  402  to process information. Although the computer system  400  is illustrated with a single processor, multiple processors and/or co-processors may also be included. 
   A random access memory (RAM) or other type of dynamic storage device  406  (depicted as main memory in  FIG. 4 ) is coupled to the bus  402  to store information and instructions to be executed by processor  404 . The main memory  406  may also be used to store temporary variables or other intermediate information during execution of instructions by a processor  404 . A read only memory (ROM) and/or other static data storage device  408  is also shown coupled to bus  402  for storing static information and other instructions carried out by processor  404 , while data storage device  410  (e.g., a magnetic disk or optical disc and corresponding drive) is coupled to bus  402  for storing information and instructions. 
   The computer system  400  may also be coupled via the bus  402  to a display device  412 , such as a cathode ray tube (CRT) or liquid crystal display (LCD), for displaying information to a computer user. An alphanumeric input device  414 , including alphanumeric and other keys, may be coupled to the bus  402  to allow a user to communicate information and command selections to the processor  404 . Another type of user input device that may be associated with computer system  400  is a cursor control device  416 , such as a mouse, a trackball, or cursor direction keys to communicate direction information and command selections to processor  404 , as well as to control cursor movement on the display device  412 . In addition, a network interface  418  may be used to provide access to a network, such as a local area network. 
   In view of the above, the present method and system embodiments may therefore take the form of computer or controller implemented processes and apparatuses for practicing those processes. The disclosure can also be embodied in the form of computer program code containing instructions embodied in tangible media, such as floppy diskettes, CD-ROMs, hard drives, or any other computer-readable storage medium, wherein, when the computer program code is loaded into and executed by a computer or controller, the computer becomes an apparatus for practicing the invention. The disclosure may also be embodied in the form of computer program code or signal, for example, whether stored in a storage medium, loaded into and/or executed by a computer or controller, or transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via electromagnetic radiation, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the invention. When implemented on a general-purpose microprocessor, the computer program code segments configure the microprocessor to create specific logic circuits. 
   While the invention has been described with reference to a preferred embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.