Abstract:
In an approach to allocating hypervisor resources for virtual machine deployment, one or more computer processors determine one or more hierarchically grouped computing resources within a hypervisor. The one or more computer processors receive a selection of one or more hierarchically grouped computing resources. The one or more computer processors apply deployment constraints for a workload to the selected one or more hierarchically grouped computing resources. The one or more computer processors determine, based, at least in part, on the deployment constraints for the workload, one or more computing resources from the one or more hierarchically grouped computing resources.

Description:
STATEMENT ON PRIOR DISCLOSURES BY AN INVENTOR 
     The following disclosure is submitted under 35 U.S.C. 102(b)(1)(A) as prior disclosures by, or on behalf of, a sole inventor of the present application or a joint inventor of the present application: 
     IBM Power Virtualization Center Standard, Installation and User&#39;s Guide, Version 1.2, dated Dec. 6, 2013. 
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to the field of computer networks, and more particularly to allocating network resources in a virtualized computer network. 
     In system virtualization, multiple virtual systems are created within a single physical system. The physical system can be a stand-alone computer, or alternatively, a computing system utilizing clustered computers and components. Virtual systems are independent operating environments that use virtual resources made up of logical divisions of physical resources such as processors, memory and input/output (I/O) adapters. This system virtualization is implemented through some managing functionality, typically hypervisor technology. Hypervisors, also called virtual machine managers (VMMs), use a thin layer of code in software or firmware to achieve fine-grained, dynamic resource sharing. Because hypervisors provide the greatest level of flexibility in how virtual resources are defined and managed, they are the primary technology for system virtualization. 
     It is a common requirement today for virtualized environments to be able to enforce strict partitioning between different classes of workload, while still sharing hardware between workloads of the same class. Separation may be required for several reasons. One reason may be to enable high availability, such that two clustered workloads do not share a single point-of-failure. Another reason is for performance guarantees, such that the resource demands of one class of resources do not affect another class. A third reason is the concern for confidentiality. For example, two competing organizations may wish to utilize a single provider of virtualized environments, with the requirement that hardware is not shared. Typically, the unit of segregation is that of a single host system, i.e. a single instance of a hypervisor. 
     Multipathing allows a virtual machine to continue to communicate with external systems when a given physical adapter, or physical port, is not operating, either due to equipment failure or due to maintenance operations such as a firmware update. Multipathing is used extensively in mission-critical workloads to ensure continuity of service during hardware failure. It is typical to ensure that no single point of failure exists between a virtual machine and the external systems to which it connects. 
     SUMMARY 
     According to one embodiment of the present invention, a method for allocating hypervisor resources for virtual machine deployment is provided. The method for allocating hypervisor resources for virtual machine deployment may include one or more computer processors determining one or more hierarchically grouped computing resources within a hypervisor. The one or more computer processors receive a selection of one or more hierarchically grouped computing resources. The one or more computer processors apply deployment constraints for a workload to the selected one or more hierarchically grouped computing resources. The one or more computer processors determine, based, at least in part, on the deployment constraints for the workload, one or more computing resources from the one or more hierarchically grouped computing resources. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a functional block diagram illustrating a virtualized computing environment, in accordance with an embodiment of the present invention; 
         FIG. 2  is a flowchart depicting operational steps of a connectivity group program, on a client computing device within the virtualized computing environment of  FIG. 1 , for creating a model of I/O connectivity groups, in accordance with an embodiment of the present invention; 
         FIG. 3  illustrates an example of the operation of a resource selection program inserted on a client computing device within the virtualized computing environment of  FIG. 1 , in accordance with an embodiment of the present invention; 
         FIG. 4  illustrates an example of the operation of a resource selection program inserted on a client computing device within the virtualized computing environment of  FIG. 1 , in accordance with an embodiment of the present invention; 
         FIG. 5  is a flowchart depicting operational steps of a resource selection program where workloads share hosts, on a client computing device within the virtualized computing environment of  FIG. 1 , for configuring a virtual machine by segregating I/O connectivity, in accordance with an embodiment of the present invention; and 
         FIG. 6  depicts a block diagram of components of the client computing device of  FIG. 1  executing the resource selection program, in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Advanced hypervisors allow a large degree of resource partitioning within a single hypervisor instance. Existing virtualization tools may not effectively capture partitioning requirements, which can span hypervisor instances, such that a user is able to effectively deploy a workload. 
     Embodiments of the present invention recognize that efficiency can be gained by implementing a model that captures many different methods of I/O connectivity segregation, such that the requirements of various classes of workload can be easily described and satisfied when a new workload is deployed. I/O connectivity includes all manner of connectivity, including ethernet networks, fibre channel, infiniband, etc. Implementation of embodiments of the invention may take a variety of forms, and exemplary implementation details are discussed subsequently with reference to the Figures. 
     The present invention will now be described in detail with reference to the Figures.  FIG. 1  is a functional block diagram illustrating a virtualized computing environment, generally designated  100 , in accordance with one embodiment of the present invention.  FIG. 1  provides only an illustration of one implementation and does not imply any limitations with regard to the environments in which different embodiments may be implemented. Many modifications to the depicted environment may be made by those skilled in the art without departing from the scope of the invention as recited by the claims. 
     Virtualized computing environment  100  includes hypervisor computer  104  and client computing device  128 , interconnected over network  102 . Network  102  can be, for example, a local area network (LAN), a wide area network (WAN), such as the Internet, or a combination of the two, and can include wired, wireless, or fiber optic connections. In general, network  102  can be any combination of connections and protocols that will support communications between hypervisor computer  104  and client computing device  128 . 
     Hypervisor computer  104  may be a management server, a web server, or any other electronic device or computing system capable of receiving and sending data. In other embodiments, hypervisor computer  104  may represent a server computing system utilizing multiple computers as a server system, such as in a cloud computing environment. In another embodiment hypervisor computer  104  may be a laptop computer, a tablet computer, a netbook computer, a personal computer (PC), a desktop computer, a personal digital assistant (PDA), a smart phone, or any programmable electronic device capable of communicating with client computing device  128  via network  102 . In another embodiment, hypervisor computer  104  represents a computing system utilizing clustered computers and components to act as a single pool of seamless resources. Hypervisor computer  104  includes virtual machine (VM)  106 , virtual I/O server  108 , virtual I/O server  110 , and physical ports  112 ,  114 ,  116 ,  118 ,  120 ,  122 ,  124 , and  126 . 
     In exemplary embodiments, VM  106  represents one or more virtual machines partitioned from hypervisor computer  104 . VM  106  is a software implemented abstraction of hardware of hypervisor computer  104 . VM  106  can be utilized to emulate functions of a physical computer (e.g., execute programs). In one embodiment, resources of hypervisor computer  104  (e.g., memory, central processing units (CPUs), storage devices, and I/O devices) can be partitioned into one or more virtual machines in VM  106 . 
     Virtual I/O server  108  and virtual I/O server  110  are responsible for taking network and storage I/O requests from virtual machines and routing the I/O requests through appropriate physical hardware to a network, such as network  102 . A given virtual machine can be configured to route I/O requests through specific virtual I/O servers. Virtual I/O server  108  and virtual I/O server  110  may also be one or more software libraries included as part of a hypervisor or a separate process or a separate virtual machine. 
     Physical ports  112 ,  114 ,  116 ,  118 ,  120 ,  122 ,  124 , and  126  reside on printed circuit boards within hypervisor computer  104  and provide a physical network interface. Physical ports  112 ,  114 ,  116 ,  118 ,  120 ,  122 ,  124 , and  126  handle the physical signaling characteristics of network media and converting the signals arriving from a network, such as network  102 , to logical values. 
     Client computing device  128  may be a desktop computer, a laptop computer, a tablet computer, a specialized computer server, a smart phone, or any programmable electronic device capable of communicating with hypervisor computer  104  via network  102  and with various components and devices within virtualized computing environment  100 . In general, client computing device  128  represents any programmable electronic device or combination of programmable electronic devices capable of executing machine-readable program instructions and communicating with other computing devices via a network, such as network  102 . Client computing device  128  includes connectivity group program  130 , database  132 , resource selection program  134 , and virtual machine (VM) deployer  136 . Client computing device  128  may include internal and external hardware components, as depicted and described in further detail with respect to  FIG. 6 . 
     Connectivity group program  130  determines the hierarchical model of a virtualization system, starting at the bottom with the physical ports and adapters up to the host system. Connectivity group program  130  categorizes physical ports to associate the ports with a specific system fabric. Connectivity group program  130  defines one or more connectivity groups comprising the physical ports associated with a system fabric. Connectivity group program  130  is depicted and described in further detail with respect to  FIG. 2 . 
     Database  132  resides on client computing device  128 . In another embodiment, database  132  may reside on hypervisor computer  104 , or on another device or component within virtualized computing environment  100  accessible via network  102 . A database is an organized collection of data. Database  132  may be implemented with any type of storage device capable of storing data that may be accessed and utilized by client computing device  128 , such as a database server, a hard disk drive, or a flash memory. In other embodiments, database  132  may represent multiple storage devices within client computing device  128 . Information stored on database  132  may include directories for data and documents used by client computing device  128 , including output from connectivity group program  130 , via network  102 . The directories and data stored on database  132  may be accessed by users of other client computing devices in virtualized computing environment  100  (not shown). 
     Resource selection program  134  selects the appropriate physical resources to use for a new virtual machine deployment, based on a set of provided constraints. The constraints include the connectivity groups defined by connectivity group program  130 , in addition to other constraints. For example, resource selection program  134  selects a physical host system that has sufficient CPU and memory resources available to run a virtual machine that is to be deployed. Resource selection program  134  selects one or more of a host system, one or more physical I/O ports that a virtual machine may use, and one or more virtual I/O servers to provide virtualized access to the one or more physical I/O ports. Resource selection program  134  is depicted and described in further detail with respect to  FIG. 5 . 
     VM deployer  136  creates a virtual machine, based on a given hardware selection made by resource selection program  134 , by communicating with the relevant hypervisor and virtual I/O servers to configure the virtual components appropriately. In some embodiments, resource selection program  134  and VM deployer  136  may reside in a VM resource manager. A VM resource manager may create new virtual machines by first utilizing resource selection program  134  to select the resources onto which the virtual machine will be deployed, and then utilizing VM deployer  136  to configure the virtual machine. 
       FIG. 2  is a flowchart depicting operational steps of connectivity group program  130 , on client computing device  128  within virtualized computing environment  100  of  FIG. 1 , for creating a model of I/O connectivity groups, in accordance with an embodiment of the present invention. 
     Connectivity group program  130  determines a hierarchy (step  202 ). Connectivity group program  130  takes an inventory of the available components in virtualized computing environment  100 . I/O virtualization environments may be represented as a hierarchy in which a physical port is associated with a specific hypervisor component, such as a virtual I/O server, which resides on a specific host, which may, in turn, be part of a larger group of hosts. An I/O path passes through a physical port. Due to the hierarchical nature of the virtualization environment, connectivity group program  130  determines groupings and dependencies between physical ports, and therefore dependencies between virtual I/O servers and host systems may be inferred, and may not need to be explicitly defined by a user. 
     Connectivity group program  130  categorizes the physical ports to indicate the associated fabrics (step  204 ). Fabrics are comprised of hardware elements such as switches, routers and gateways, and associated cabling. A fabric, or system fabric, is a network of connected systems that shares no physical infrastructure with other fabrics. A fabric is a means of connectivity between a server and other parts of the system, such as storage or the network. Having several fabrics within a system ensures redundancy to ensure a measure of fault tolerance. Connectivity group program  130  categorizes, or tags, each physical port with an indication of the specific fabric to which the port is connected. In one embodiment, connectivity group program  130  automatically discovers the categorization by programmatic interaction with the fabrics. In another embodiment, a user may provide the categorization. By categorizing each physical port with the fabric on which it resides, the redundancy offered by any given virtual I/O server, host, or ensemble (a collection of host systems) may be determined. Such a model not only allows new workloads to be created with a specified level of fault-tolerance, but also allows components with equivalent connectivity to be identified. 
     Connectivity group program  130  defines connectivity groups (step  206 ). Connectivity group program  130  creates a named grouping of physical ports, referred to as a connectivity group. In one embodiment, connectivity groups are defined programmatically. For example, connectivity group program  130  may divide the resources evenly between workload categories. In another embodiment, connectivity group program  130  receives input from a system administrator for the definition of which ports belong to which connectivity groups. Connectivity group program  130  stores the defined connectivity groups in database  132 . Defining the connectivity groups creates a model for virtual machine deployment. At the time of creation of a virtual machine, a system administrator selects one or more connectivity groups for deployment. 
       FIG. 3  illustrates example  300  of the operation of resource selection program  134  inserted on client computing device  128  within virtualized computing environment  100  of  FIG. 1 , in accordance with an embodiment of the present invention. 
     In the example, a system administrator plans to separate workloads by host system. Two connectivity groups have been defined via the steps described with respect to connectivity group program  130 . Connectivity group  302  is defined as “Production”. Connectivity group  304  is defined as “Development”. Production workloads are processed on host  310 , which includes virtual I/O servers  311  and  312 , and host  320 , which includes virtual I/O servers  321  and  322 . Development workloads are processed on host  330 , which includes virtual I/O servers  331  and  332 , and host  340 , which includes virtual I/O servers  341  and  342 . The physical ports categorized, or tagged, “port  0 ” are on fabric A, and the physical ports categorized “port  1 ” are on fabric B. Production connectivity group  302  contains the eight ports from host  310  and host  320 . Development connectivity group  304  contains the eight ports from host  330  and host  340 . 
     With the connectivity group configuration in place, the system administrator may deploy a workload to production connectivity group  302  or development connectivity group  304 . In this example, a production workload is deployed, therefore the system administrator selects production connectivity group  302 . In addition, a constraint of path redundancy is applied. 
     By implication of the hierarchy, the choice of hosts is host  310  or host  320  because those are the hosts containing production physical ports. In this example, resource selection program  134  selects host  310 . A host is selected based on a variety of criteria and constraints applied by the system administrator prior connectivity group selection, including load-balancing across hosts, maximizing the number of unused hosts, placing complementary workloads close to each other, etc. 
     Because the selected host is host  310 , virtual I/O servers  311  and  312  are candidates for providing the I/O path to the virtual machine. Because path redundancy is required, resource selection program  134  selects both virtual I/O servers. 
     On each virtual I/O server of host  310 , both physical ports, port  0  and port  1 , are part of production connectivity group  302 . Port  0  of both virtual I/O server  311  and virtual I/O server  312  is connected to system fabric A. Port  1  of both virtual I/O server  311  and virtual I/O server  312  is connected to fabric B. Because path redundancy is required, resource selection program  134  selects both physical ports on virtual I/O server  311  and on virtual I/O server  312 . 
     The selections result in a new production virtual machine, configured on a host with a total of four paths to external systems, passing through each of two virtual I/O servers onto each of two system fabrics. Resource selection program  134  sends the virtual machine configuration to VM deployer  136  for workload deployment. 
       FIG. 4  illustrates example  400  of the operation of resource selection program  134  inserted on client computing device  128  within virtualized computing environment  100  of  FIG. 1 , in accordance with an embodiment of the present invention. 
     In example  400 , similar to example  300  discussed earlier, two connectivity groups have been defined via the steps described with respect to connectivity group program  130 . Connectivity group  402  is defined as “Production”. Connectivity group  404  is defined as “Development”. In this example, there are two hosts, host  410  and host  420 , and there are two virtual I/O servers on each host. Host  410  includes virtual I/O servers  411  and  412 . Host  420  includes virtual I/O servers  421  and  422 . The virtual I/O servers have physical ports that are dedicated for use by specific connectivity groups, based on the categorization. The physical ports categorized, or tagged, “port  0 ” and “port  2 ” are on fabric A, and the physical ports categorized “port  1 ” and “port  3 ” are on fabric B. Production connectivity group  402  contains four ports from host  410  and four ports from host  420 . Development connectivity group  304  also contains four ports from host  410  and four ports from host  420 . 
     With the connectivity group configuration in place, the system administrator may deploy a workload to production connectivity group  402  or development connectivity group  404 . In this example, a production workload is deployed, therefore the system administrator selects production connectivity group  402 . In addition, a constraint of path redundancy is applied. 
     By implication of the hierarchy, resource selection program  134  determines the choice of hosts is host  410  or host  420  because both hosts contain production physical ports. In this example, resource selection program  134  selects host  410 . 
     Because the selected host is host  410 , virtual I/O servers  411  and  412  are candidates for providing the I/O path to the virtual machine. Because path redundancy is required, resource selection program  134  selects both virtual I/O servers. 
     On each virtual I/O server, only port  0  and port  1  are part of production connectivity group  402 , and one port is connected to each fabric. Because path redundancy is required, resource selection program  134  selects port  0  and port  1  on virtual I/O server  411  and port  0  and port  1  on virtual I/O server  412 . 
     The selections result in a new production virtual machine, configured on a host with a total of four paths to external systems, passing through each of two virtual I/O servers onto each of two system fabrics. The production and development workloads are segregated at the port level such that development I/O does not impact the bandwidth available for production I/O. Resource selection program  134  sends the virtual machine configuration to VM deployer  136  for workload deployment. 
       FIG. 5  is a flowchart depicting operational steps of resource selection program  134  where workloads share hosts, on client computing device  128  within virtualized computing environment  100  of  FIG. 1 , for configuring a virtual machine by segregating I/O connectivity, in accordance with an embodiment of the present invention. 
     Resource selection program  134  receives a connectivity group selection (step  502 ). Based on the categorization of the connectivity groups, a system administrator selects the appropriate connectivity group from database  132  for the current deployment activity. In example  300 , the current deployment is for a production virtual machine, therefore resource selection program  134  receives the selection of production connectivity group  302 . 
     Resource selection program  134  applies constraints to the selected connectivity group (step  504 ). For example, if the system administrator determines that redundancy is a requirement of the workload deployment, then resource selection program  134  may apply the constraint that the chosen host must include ports in the selected connectivity group that are connected to different fabrics to ensure continuity of service during a hardware failure. In another example, resource selection program  134  may apply a constraint of a particular storage controller to be used in the workload deployment. In a further example, resource selection program  134  may apply a constraint regarding memory requirements, because not all hosts have enough memory for a particular workload deployment. 
     Resource selection program  134  selects host(s) (step  506 ). Based on the system hierarchy and the categorization of the connectivity groups, resource selection program  134  selects one or more hosts that meet the requirements of the workload deployment and the previously applied constraints. In example  300 , resource selection program  134  selects host  310  because host  310  contains production physical ports. 
     Resource selection program  134  selects virtual I/O server(s) (step  508 ). Based on the host selected in the previous step, resource selection program  134  selects the available virtual I/O server, such as virtual I/O server  108  in  FIG. 1 , in the connectivity group that meets the requirements of the workload deployment and the previously applied constraints. In example  300 , resource selection program  134  selects virtual I/O server  311  and virtual I/O server  312  because both are connected to host  310 , which includes ports connected to different fabrics, and redundancy is a requirement. 
     Resource selection program  134  selects physical port(s) (step  510 ). Based on the previously selected virtual I/O server and the categorization, or tagging, of the physical ports to a specific fabric, resource selection program  134  selects one or more physical ports that meet the requirements of the workload deployment and the previously applied constraints. In example  300 , resource selection program  134  selects both physical ports on each virtual I/O server because redundancy is a requirement. 
     Resource selection program  134  sends the selections to VM deployer  136  (step  512 ). As discussed earlier, VM deployer  136  is responsible for creating a virtual machine, based on the selections made by resource selection program  134  in the previous five steps. Responsive to completion of the previous five steps, resource selection program  134  sends the selections to VM deployer  136  for workload deployment and creation of a virtual machine. 
     In another embodiment, resource selection program  134  may be used during workload relocation operations. A VM may be moved from one physical host to a second physical host for one or more of a plurality of reasons, for example, load-balancing, evacuation of a failing component, or to satisfy the need to place a given workload closer to some external systems. The VM continues to have the same connectivity and fault-tolerance requirements on the second physical host. Using resource selection program  134  to select resources on the second physical host ensures the expected connectivity is maintained. 
     In another embodiment, resource selection program  134  may be applied to the selection of other physical resources, in addition to I/O resources. Resource selection program  134  may be applied where a system administrator prefers specific direction to allow or deny access to a resource for specific groups of users or types of workload. For example, resource selection program  134  may be used to select cryptographic acceleration hardware, graphics processing units (GPU), field programmable gate arrays (FPGAs), etc. 
       FIG. 6  depicts a block diagram of components of client computing device  128  of  FIG. 1  in accordance with an illustrative embodiment of the present invention. It should be appreciated that  FIG. 6  provides only an illustration of one implementation and does not imply any limitations with regard to the environments in which different embodiments may be implemented. Many modifications to the depicted environment may be made. 
     Client computing device  128  includes communications fabric  602 , which provides communications between computer processor(s)  604 , memory  606 , persistent storage  608 , communications unit  610 , and input/output (I/O) interface(s)  612 . Communications fabric  602  can be implemented with any architecture designed for passing data and/or control information between processors (such as microprocessors, communications, and network processors, etc.), system memory, peripheral devices, and any other hardware components within a system. For example, communications fabric  602  can be implemented with one or more buses. 
     Memory  606  and persistent storage  608  are computer readable storage media. In this embodiment, memory  606  includes random access memory (RAM)  614  and cache memory  616 . In general, memory  606  can include any suitable volatile or non-volatile computer readable storage media. 
     Connectivity group program  130 , database  132 , resource selection program  134 , and virtual machine deployer  136  are stored in persistent storage  608  for execution by one or more of the respective computer processor(s)  604  via one or more memories of memory  606 . In this embodiment, persistent storage  608  includes a magnetic hard disk drive. Alternatively, or in addition to a magnetic hard disk drive, persistent storage  608  can include a solid-state hard drive, a semiconductor storage device, a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, or any other computer readable storage media that is capable of storing program instructions or digital information. 
     The media used by persistent storage  608  may also be removable. For example, a removable hard drive may be used for persistent storage  608 . Other examples include optical and magnetic disks, thumb drives, and smart cards that are inserted into a drive for transfer onto another computer readable storage medium that is also part of persistent storage  608 . 
     Communications unit  610 , in these examples, provides for communications with other data processing systems or devices, including resources of hypervisor computer  104 . In these examples, communications unit  610  includes one or more network interface cards. Communications unit  610  may provide communications through the use of either or both physical and wireless communications links. Connectivity group program  130 , database  132 , resource selection program  134 , and virtual machine deployer  136  may be downloaded to persistent storage  608  through communications unit  610 . 
     I/O interface(s)  612  allows for input and output of data with other devices that may be connected to client computing device  128 . For example, I/O interface(s)  612  may provide a connection to external device(s)  618  such as a keyboard, a keypad, a touch screen, and/or some other suitable input device. External device(s)  618  can also include portable computer readable storage media such as, for example, thumb drives, portable optical or magnetic disks, and memory cards. Software and data used to practice embodiments of the present invention, e.g., connectivity group program  130 , database  132 , resource selection program  134 , and virtual machine deployer  136 , can be stored on such portable computer readable storage media and can be loaded onto persistent storage  608  via I/O interface(s)  612 . I/O interface(s)  612  also connect to a display  620 . 
     Display  620  provides a mechanism to display data to a user and may be, for example, a computer monitor. 
     The programs described herein are identified based upon the application for which they are implemented in a specific embodiment of the invention. However, it should be appreciated that any particular program nomenclature herein is used merely for convenience, and thus the invention should not be limited to use solely in any specific application identified and/or implied by such nomenclature. 
     The present invention may be a system, a method, and/or a computer program product. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present invention. 
     The computer readable storage medium can be any tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire. 
     Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network, and/or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers, and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device. 
     Computer readable program instructions for carrying out operations of the present invention may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object-oriented programming language such as Smalltalk, C++ or the like, and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program instructions may execute entirely on the user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer, or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present invention. 
     Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions. 
     These computer readable program instructions may be provided to a processor of a general purpose computer, a special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks. 
     The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus, or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks. 
     The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the Figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions. 
     The descriptions of the various embodiments of the present invention have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The terminology used herein was chosen to best explain the principles of the embodiment, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.