Patent Publication Number: US-8543687-B2

Title: Moving deployment of images between computers

Description:
FIELD 
     An embodiment of the invention generally relates to cloud computing and more particularly to moving deployment of images between computers that are members of a cloud. 
     BACKGROUND 
     Computer systems typically comprise a combination of computer programs and hardware, such as semiconductors, transistors, chips, circuit boards, storage devices, and processors. The computer programs are stored in the storage devices and are executed by the processors. 
     One use of computer systems is in cloud computing, in which shared resources, such as computer programs and data stored on computer servers organized as members of a cloud are provided to client computers and other devices on-demand, analogous to a public utility, such as an electricity or telephone company. The cloud typically has multiple computer servers called nodes, which are managed as a group and which share similar properties. The similar properties of nodes within a cloud allow tasks, which need to be repeated on many nodes, such as installing or deploying programs, often called images, to be applied to a group of nodes. Similar properties of nodes within a cloud also allow images to be installed or deployed to any node within a cloud or moved between nodes in a cloud without modifying the image. 
     SUMMARY 
     A method, computer-readable storage medium, and computer system are provided. In an embodiment, a unit workload is calculated. The unit workload comprises an average processor speed and an average memory amount required by execution of images. If an integer multiple of the average processor speed required by the execution of the images minus a free processor speed at a source computer is greater than a first threshold amount, an integer multiple of the average memory amount required by the execution of the images minus a free memory amount at the source computer is greater than a second threshold amount, the integer multiple of the average processor speed required minus a processor speed requirement of a source image at the source computer is less than a third threshold amount, and the integer multiple of the average memory required minus a memory requirement of the source image at the source computer is less than a fourth threshold amount, then deployment of the source image is moved from the source computer to a destination computer. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  depicts a high-level block diagram of an example system for implementing an embodiment of the invention. 
         FIG. 2  depicts a block diagram illustrating servers connected via a network, according to an embodiment of the invention. 
         FIG. 3  depicts a block diagram of an example data structure for a servers description, according to an embodiment of the invention. 
         FIG. 4  depicts a block diagram of an example data structure for resource requirements, according to an embodiment of the invention. 
         FIG. 5  depicts a block diagram of an example data structure for a unit workload for all users, according to an embodiment of the invention. 
         FIG. 6  depicts a block diagram of an example data structure for node deployments, according to an embodiment of the invention. 
         FIG. 7  depicts a block diagram of an example data structure for a deployment history, according to an embodiment of the invention. 
         FIG. 8  depicts a block diagram of an example data structure for a unit workload for a specified user, according to an embodiment of the invention. 
         FIG. 9  depicts a flowchart of example processing for creating a unit workload and node deployments, according to an embodiment of the invention. 
         FIG. 10  depicts a flowchart of example processing for creating a unit workload for all users, according to an embodiment of the invention. 
         FIG. 11  depicts a flowchart of example processing for creating a unit workload for a specified user, according to an embodiment of the invention. 
         FIG. 12  depicts a flowchart of example processing for calculating node deployments, according to an embodiment of the invention. 
         FIG. 13  depicts a flowchart of example processing for defragmenting deployed images, according to an embodiment of the invention. 
         FIG. 14  depicts a flowchart of example processing for moving deployed images between servers, according to an embodiment of the invention. 
     
    
    
     It is to be noted, however, that the appended drawings illustrate only example embodiments of the invention, and are therefore not considered a limitation of its scope, for the invention may admit to other equally effective embodiments. 
     DETAILED DESCRIPTION 
     Referring to the Drawings, wherein like numbers denote like parts throughout the several views,  FIG. 1  depicts a high-level block diagram representation of a computer system  100  connected to clouds  131  and  133  of respective computer servers  132  and  134  via a network  130 , according to an embodiment of the present invention. The major components of the computer system  100  include one or more processors  101 , a main memory  102 , a terminal interface  111 , a storage interface  112 , an I/O (Input/Output) device interface  113 , and a network adapter  114 , all of which are communicatively coupled, directly or indirectly, for inter-component communication via a memory bus  103 , an I/O bus  104 , and an I/O bus interface unit  105 . 
     The computer system  100  contains one or more general-purpose programmable central processing units (CPUs)  101 A,  101 B,  101 C, and  101 D, herein generically referred to as the processor  101 . In an embodiment, the computer system  100  contains multiple processors typical of a relatively large system; however, in another embodiment the computer system  100  may alternatively be a single CPU system. Each processor  101  executes instructions stored in the main memory  102  and may include one or more levels of on-board cache. 
     The main memory  102  is a random-access semiconductor memory, storage device, or storage medium for storing or encoding data and programs. In another embodiment, the main memory  102  represents the entire virtual memory of the computer system  100 , and may also include the virtual memory of other computer systems coupled to the computer system  100  or connected via the network  130 . The main memory  102  is conceptually a single monolithic entity, but in other embodiments the main memory  102  is a more complex arrangement, such as a hierarchy of caches and other memory devices. For example, memory may exist in multiple levels of caches, and these caches may be further divided by function, so that one cache holds instructions while another holds non-instruction data, which is used by the processor or processors. Memory may be further distributed and associated with different CPUs or sets of CPUs, as is known in any of various so-called non-uniform memory access (NUMA) computer architectures. 
     The main memory  102  stores or encodes an image library  150 , a servers description  152 , resource requirements  154 , a deployment service  156 , a unit workload  158 , node deployments  160 , a deployment history  162 , and a defragmenter  164 . Although the image library  150 , the servers description  152 , the resource requirements  154 , the deployment service  156 , the unit workload  158 , the node deployments  160 , the deployment history  162 , and the defragmenter  164  are illustrated as being contained within the memory  102  in the computer system  100 , in other embodiments some or all of them may be on different computer systems and may be accessed remotely, e.g., via the network  130 . The computer system  100  may use virtual addressing mechanisms that allow the programs of the computer system  100  to behave as if they only have access to a large, single storage entity instead of access to multiple, smaller storage entities. Thus, while the image library  150 , the servers description  152 , the resource requirements  154 , the deployment service  156 , the unit workload  158 , the node deployments  160 , the deployment history  162 , and the defragmenter  164  are illustrated as being contained within the main memory  102 , these elements are not necessarily all completely contained in the same storage device at the same time. Further, although the image library  150 , the servers description  152 , the resource requirements  154 , the deployment service  156 , the unit workload  158 , the node deployments  160 , the deployment history  162 , and the defragmenter  164  are illustrated as being separate entities, in other embodiments some of them, portions of some of them, or all of them may be packaged together. 
     The image library  150  comprises images, which comprise executable programs, methods, procedures, routines, classes, objects, instructions, or statements. The deployment service  156  or another program deploys or sends the images to computer servers  132  and  134 , where the images are stored in memory and installed, configured, and executed on the processors of the computer servers  132  and  134 . In various embodiments, some or all of the computer servers  132  and  134  receive the same images from the image library  150 . In other embodiments, some or all of the computer servers  132  and  134  receive different images from the image libraries  150 . 
     The servers description  152  describes the attributes and free or available resources (e.g., memory, processors, storage devices, and network bandwidth) of the computer servers  132  and  134 . The images from the library  150  use the free resources during execution at the computer servers  132  and  134 . The resource requirements  154  specifies the amount of the free resources at the servers  132  and  134  that the images need and the type or attributes of the computer servers  132  and  134  that the images need or use, in order to execute on the processors of the computer servers  132  and  134 . 
     The deployment service  156  calculates the unit workload  158  and the node deployments  160 . The unit workload  158  describes, for all users or for a specified user, the average resource requirements of an average image in the image library  150 . The node deployments  160  describes the number of the average images that are deployable to the servers. The deployment history  162  describes a history of various images that various users have deployed to the servers  132  and  134 . The defragmenter  164  determines whether to un-deploy or remove images in the image library  150  from the computer servers  132  and  134  and whether to move images between the computer servers  132  and  134 . 
     In various embodiments, one, some, or all of the image library  150 , the deployment service  156 , and the defragmenter  164  include instructions or statements that execute on the processor  101  or instructions or statements that are interpreted by instructions or statements that execute on the processor  101 , to carry out the functions as further described below with reference to  FIGS. 9 ,  10 ,  11 ,  12 ,  13 , and  14 . In an embodiment, one, some, or all of the image library  150 , the deployment service  156 , and the defragmenter  164  are implemented in hardware via semiconductor devices, chips, logical gates, circuits, circuit cards, and/or other physical hardware devices in lieu of, or in addition to, a processor-based system. 
     The memory bus  103  provides a data communication path for transferring data among the processor  101 , the main memory  102 , and the I/O bus interface unit  105 . The I/O bus interface unit  105  is further coupled to the system I/O bus  104  for transferring data to and from the various I/O units. The I/O bus interface unit  105  communicates with multiple I/O interface units  111 ,  112 ,  113 , and  114 , which are also known as I/O processors (IOPs) or I/O adapters (IOAs), through the system I/O bus  104 . 
     The I/O interface units support communication with a variety of storage and I/O devices. For example, the terminal interface unit  111  supports the attachment of one or more user input/output devices  121 , which may include user output devices (such as a video display device, speaker, printer, and/or television set) and user input devices (such as a keyboard, mouse, keypad, touchpad, trackball, buttons, light pen, or other pointing device). A user may manipulate the user input devices, in order to provide input to the user input/output device  121  and the computer system  100  via a user interface, and may receive output via the user output devices. For example, a user interface may be presented via the user input/output device  121 , such as displayed on a display device, played via a speaker, or printed via a printer. 
     The storage interface unit  112  supports the attachment of one or more direct access storage devices (DASD)  125  and  126  (which are typically rotating magnetic disk drive storage devices, although they could alternatively be other devices, including arrays of disk drives configured to appear as a single large storage device to a host). In another embodiment, the devices  125  and/or  126  may be implemented via any type of secondary storage device. The contents of the main memory  102 , or any portion thereof, may be stored to and retrieved from the direct access storage devices  125  and  126 , as needed. 
     The I/O device interface  113  provides an interface to any of various other input/output devices or devices of other types, such as printers or fax machines. The network adapter  114  provides one or more communications paths from the computer system  100  to other digital devices and computer systems; such paths may include, e.g., one or more networks  130 . 
     Although the memory bus  103  is shown in  FIG. 1  as a relatively simple, single bus structure providing a direct communication path among the processors  101 , the main memory  102 , and the I/O bus interface  105 , in fact the memory bus  103  may comprise multiple different buses or communication paths, which may be arranged in any of various forms, such as point-to-point links in hierarchical, star or web configurations, multiple hierarchical buses, parallel and redundant paths, or any other appropriate type of configuration. Furthermore, while the I/O bus interface  105  and the I/O bus  104  are shown as single respective units, the computer system  100  may, in fact, contain multiple I/O bus interface units  105  and/or multiple I/O buses  104 . While multiple I/O interface units are shown, which separate the system I/O bus  104  from various communications paths running to the various I/O devices, in other embodiments some or all of the I/O devices are connected directly to one or more system I/O buses. 
     In various embodiments, the computer system  100  may be a multi-user “mainframe” computer system, a single-user system, or a server or similar device that has little or no direct user interface, but receives requests from other computer systems (clients). In other embodiments, the computer system  100  may be implemented as a desktop computer, portable computer, laptop or notebook computer, tablet computer, pocket computer, telephone, pager, automobile, teleconferencing system, appliance, or any other appropriate type of electronic device. 
     The network  130  may be any suitable network or combination of networks and may support any appropriate protocol suitable for communication of data and/or code to/from the computer system  100 . In various embodiments, the network  130  may represent a storage device or a combination of storage devices, either connected directly or indirectly to the computer system  100 . In another embodiment, the network  130  may support wireless communications. In another embodiment, the network  130  may support hard-wired communications, such as a telephone line or cable. In another embodiment, the network  130  may be the Internet and may support IP (Internet Protocol). 
     In another embodiment, the network  130  may be a local area network (LAN) or a wide area network (WAN). In another embodiment, the network  130  may be a hotspot service provider network. In another embodiment, the network  130  may be an intranet. In another embodiment, the network  130  may be a GPRS (General Packet Radio Service) network. In another embodiment, the network  130  may be a FRS (Family Radio Service) network. In another embodiment, the network  130  may be any appropriate cellular data network, cell-based radio network. In still another embodiment, the network  130  may be any suitable network or combination of networks. Although one network  130  is shown, in other embodiments any number of networks (of the same or different types) may be present. 
     The cloud  131  comprises computer servers  132 , which share common attributes, such as a type of processor that executes images received from the image library  150 . The cloud  133  comprises computer servers  134 , which share common attributes. The computer servers  132  and  134  may include some or all of the hardware and/or program components previously described above for the computer system  100 . 
     It should be understood that  FIG. 1  is intended to depict the representative major components of the computer system  100 , the network  130 , and the clouds  131  and  133  at a high level, that individual components may have greater complexity than represented in  FIG. 1 , that components other than or in addition to those shown in  FIG. 1  may be present, and that the number, type, and configuration of such components may vary. Several particular examples of such additional complexity or additional variations are disclosed herein; it being understood that these are by way of example only and are not necessarily the only such variations. 
     The various program components illustrated in  FIG. 1  and implementing various embodiments of the invention may be implemented in a number of manners, including using various computer applications, routines, components, programs, objects, modules, data structures, etc., and are referred to hereinafter as “computer programs,” or simply “programs.” The computer programs comprise one or more instructions or statements that are resident at various times in various memory and storage devices in the computer systems  100 ,  132 , and  134  and that, when read and executed by one or more processors in the computer system  100 ,  132 , and  134  or when interpreted by instructions that are executed by one or more processors, cause the computer systems  100 ,  132 , and  134  to perform the actions necessary to execute steps or elements comprising the various aspects of embodiments of the invention. 
     As will be appreciated by one skilled in the art, aspects of embodiments of the present invention may be embodied as a system, method, or computer program product. Accordingly, aspects of embodiments of the present invention may take the form of an entirely hardware embodiment, an entirely program embodiment (including firmware, resident programs, micro-code, etc., which are stored in a storage device) or an embodiment combining program and hardware aspects that may all generally be referred to herein as a “circuit,” “module,” or “system.” Furthermore, embodiments of the present invention may take the form of a computer program product embodied in one or more computer-readable medium(s) having computer-readable program code embodied thereon. 
     Any combination of one or more computer-readable medium(s) may be utilized. The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium, may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (an non-exhaustive list) of the computer-readable storage media may comprise: an electrical connection having one or more wires, 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, an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer-readable storage medium may be any tangible non-transitory medium that can contain, or store, a program for use by or in connection with an instruction execution system, apparatus, or device. 
     A computer-readable signal medium may comprise a propagated data signal with computer-readable program code embodied thereon, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer-readable signal medium may be any computer-readable medium that is not a computer-readable storage medium and that communicates, propagates, or transports a program for use by, or in connection with, an instruction execution system, apparatus, or device. 
     Program code embodied on a computer-readable medium may be transmitted using any appropriate medium, including but not limited to, wireless, wire line, optical fiber cable, Radio Frequency (RF), or any suitable combination of the foregoing. 
     Computer program code for carrying out operations for aspects of embodiments of the present invention may be written in any combination of one or more programming languages, including object oriented programming languages and conventional procedural programming languages. The program code may execute entirely on the user&#39;s computer, 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). 
     Aspects of embodiments of the present invention are described below with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products. Each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams may be implemented by computer program instructions embodied in a computer-readable medium. These computer program instructions may be provided to a processor of a general purpose computer, 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 by the flowchart and/or block diagram block or blocks. 
     These computer program instructions may also be stored in a computer-readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer-readable medium produce an article of manufacture, including instructions that implement the function/act specified by the flowchart and/or block diagram block or blocks. The computer programs defining the functions of various embodiments of the invention may be delivered to a computer system via a variety of tangible computer-readable storage media that may be operatively or communicatively connected (directly or indirectly) to the processor or processors. 
     The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus, or other devices to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide processes for implementing the functions/acts specified in the flowcharts and/or block diagram block or blocks. 
     The flowchart and the 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 flowcharts or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, 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 should also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flow chart illustrations, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, in combinations of special purpose hardware and computer instructions. 
     Embodiments of the present invention may also be delivered as part of a service engagement with a client corporation, nonprofit organization, government entity, or internal organizational structure. Aspects of these embodiments may comprise configuring a computer system to perform, and deploying computing services (e.g., computer-readable code, hardware, and web services) that implement, some or all of the methods described herein. Aspects of these embodiments may also comprise analyzing the client company, creating recommendations responsive to the analysis, generating computer-readable code to implement portions of the recommendations, integrating the computer-readable code into existing processes, computer systems, and computing infrastructure, metering use of the methods and systems described herein, allocating expenses to users, and billing users for their use of these methods and systems. 
     In addition, various programs described hereinafter may be identified based upon the application for which they are implemented in a specific embodiment of the invention. But, any particular program nomenclature that follows is used merely for convenience, and thus embodiments of the invention should not be limited to use solely in any specific application identified and/or implied by such nomenclature. 
     The exemplary environments illustrated in  FIG. 1  are not intended to limit the present invention. Indeed, other alternative hardware and/or program environments may be used without departing from the scope of embodiments the invention. 
       FIG. 2  depicts a block diagram illustrating an example deployment of images from the image library to computer servers connected via a network, according to an embodiment of the invention.  FIG. 2  illustrates the computer system  100  and server computer system nodes  132 - 1 ,  132 - 2 ,  132 - 3 ,  132 - 4 ,  132 - 5 ,  132 - 6 ,  132 - 7 ,  132 - 8 , and  132 - 9  connected via the network  130 . The server computer system nodes  132 - 1 ,  132 - 2 ,  132 - 3 ,  132 - 4 ,  132 - 5 ,  132 - 6 ,  132 - 7 ,  132 - 8 , and  132 - 9  are examples of, and are generically referred to by, the computer system  132  ( FIG. 1 ). Each of the server computer system nodes  132 - 1 ,  132 - 2 ,  132 - 3 ,  132 - 4 ,  132 - 5 ,  132 - 6 ,  132 - 7 ,  132 - 8 , and  132 - 9  comprises a respective processor  101 - 1 ,  101 - 2 ,  101 - 3 ,  101 - 4 ,  101 - 5 ,  101 - 6 ,  101 - 7 ,  101 - 8 , and  101 - 9  connected to respective memory  102 - 1 ,  102 - 2 ,  102 - 3 ,  102 - 4 ,  102 - 5 ,  102 - 6 ,  102 - 7 ,  102 - 8 , and  102 - 9  via a respective bus. Each of the processors  101 - 1 ,  101 - 2 ,  101 - 3 ,  101 - 4 ,  101 - 5 ,  101 - 6 ,  101 - 7 ,  101 - 8 , and  101 - 9  is an example of, and is generically referred to by the processor  101  ( FIG. 1 ). Each of the memory  102 - 1 ,  102 - 2 ,  102 - 3 ,  102 - 4 ,  102 - 5 ,  102 - 6 ,  102 - 7 ,  102 - 8 , and  102 - 9  is an example of, and is generically referred to by the memory  102  ( FIG. 1 ). 
     The memory  102 - 1  in the server computer system node  132 - 1  stores two copies of the image A  150 - 1  and one copy of the image B  150 - 2 , which execute on the processor  101 - 1  and use or consume resources of the server computer system node  132 - 1  that were free prior to the deployment of the images to the server computer system node  132 - 1 . The memory  102 - 2  in the server computer system node  132 - 2  stores the image B  150 - 2 , which executes on the processor  101 - 2  and uses or consumes resources of the server computer system node  132 - 2 . The memory  102 - 3  in the server computer system node  132 - 3  stores the image B  150 - 2 , which executes on the processor  101 - 3  and uses or consumes resources of the server computer system node  132 - 3 . The memory  102 - 9  in the server computer system node  132 - 9  stores the image C  150 - 3 , which executes on the processor  101 - 9  and uses or consumes resources of the server computer system node  132 - 9 . The images  150 - 1 ,  150 - 2 , and  150 - 3  are subsets of the image library  150  ( FIG. 1 ). 
       FIG. 3  depicts a block diagram of an example data structure for the servers description  152 , according to an embodiment of the invention. The servers description  152  comprises example entries  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  314 ,  316 ,  318 , and  320 , each of which comprises an example node identifier field  330 , an example free processor speed field  332 , an example free memory field  334 , an example processor architecture field  336 , and an example cloud identifier field  338 . 
     The node identifier field  330  identifies a computer server node, such as the computer server  132  or  134 . The free processor speed field  332  specifies the amount of free, unused, or unallocated processor speed (at the computer system node identified by the node identifier  330  in the same entry) that is available for use or available to be allocated to an image that is not yet deployed, installed, or executing at the computer system node. In an embodiment, the free processor speed for a server computer system node equals the total processor speed at the server computer system node minus the sum of the processor speed requirements for all images currently installed or deployed at the server computer system node, regardless of how much of the total processor speed the currently deployed and installed images actually use. In another embodiment, the free processor speed  332  for a server computer system node equals the total processor speed at the server computer system node minus the sum of the amount of processor speed currently used by the images installed, deployed, and executing at the server computer system node. In various embodiments, the free processor speed  332  is expressed in units of an executable instructions rate (e.g., instructions executed per second or any multiple thereof), a clock frequency (e.g., hertz or any multiple thereof), or an executable floating point operations rate (e.g., floating point operations per second or any multiple thereof). 
     The free memory field  334  specifies the amount of free, unused, or unallocated memory (at the computer system node identified by the node identifier  330  in the same entry) that is available for use or available to be allocated to an image that is not yet deployed, installed, or executing at the computer system node. The free memory  334  for a server computer system node equals the amount of installed memory at the server computer system node minus the sum of the memory requirements for all images currently installed at the server computer system node, regardless of how much memory the currently installed images actually use. In another embodiment, the free memory  334  for a server computer system node equals the total amount or quantity of memory at the server computer system node minus the sum of the amount of memory currently used by the images installed, deployed, and executing at the server computer system node. 
     The processor architecture field  336  specifies the type of architecture of the processors (or the type of the instruction set that the processors execute) that are installed at the server computer system node (identified by the node identifier  330  in the same entry). The cloud identifier field  338  specifies the cloud  131  or  133  of which the computer server node (identified by the node identifier field  330  in the same entry) is a member. In an embodiment, all computer system nodes that are members of the same cloud comprise processors with the same processor architecture, and computer system nodes that are members of different clouds may have, but are not necessarily required to have, different processor architectures. 
       FIG. 4  depicts a block diagram of an example data structure for the resource requirements  154 , according to an embodiment of the invention. In an embodiment, the data structure for resource requirements  154  is implemented in the Open Virtual Machine Format (OVF), but any other embodiments any appropriate format, organization, or structure may be used. The example resource requirements  154  comprises example entries  402 ,  404 ,  406 ,  408 ,  410 , and  412 , each of which comprises an example image identifier field  420 , a processor speed requirement field  422 , a memory requirement field  424 , and a processor architecture requirement field  426 . 
     The image identifier field  420  specifies an image in the image library  150 . The processor speed requirement field  422  specifies the amount of processor speed that is needed by the image (identified by the image identifier  420  in the same entry) when the image is installed at a server computer system node. In various embodiments, the processor speed requirement field  422  specifies the maximum processor speed that the image needs, the minimum processor speed that the image needs, or the average processor speed that the image needs in order to execute. 
     The memory requirement field  424  specifies the amount of memory that is needed by the image (identified by the image identifier  420  in the same entry) when the image is installed at a server computer system node. In various embodiments, the memory requirement field  424  specifies the maximum amount of memory that the image needs, the minimum amount of memory that the image needs, or the average amount of memory that the image needs in order to execute. The processor architecture requirement  426  specified the type of processor architecture that the image (identified by the image identifier  420  in the same entry) needs in order to execute at a server computer system node. The entries  402 ,  404   406 ,  408 ,  410 , and  412  represent the resource requirements for all of the images in the image library  150 , regardless of whether the images are actually deployed, installed, configured, and executing at the computer servers or not actually deployed, installed, configured and executing at the computer servers. 
       FIG. 5  depicts a block diagram of an example data structure for a unit workload  158 - 1  for all users, according to an embodiment of the invention. The unit workload  158 - 1  is an example of, and is generically referred to by, the unit workload  158  ( FIG. 1 ). The unit workload  158 - 1  comprises an image identifier field  522 , a processor speed field  524 , a memory field  526 , and a processor architecture field  528 . The image identifier field  522  specifies the images in the image library  150  that are represented by the unit workload  158 - 1 . The processor speed field  524  specifies the average processor speed required by execution of the images specified by the image identifier field  522 . The memory field  526  specifies the average memory amount required by execution of the images specified by the image identifier field  522 . The processor architecture field  528  specifies the processor architecture that is required by the images specified by the image identifiers  522 , in order for the images to execute. 
     The unit workload  158 - 1  describes, for all users (regardless of which user requested the deployment of the images identified by the image identifiers  522 ), the average resource requirements (the average required processor speed  524  and the average amount of memory  526  required) for the images identified by the image identifiers  522  to execute on a processor in a server computer system node. The image identifiers  522  identify images in the image library  150  that are members of the same cloud or that execute on a processor having the same processor architecture. 
       FIG. 6  depicts a block diagram of an example data structure for the node deployments  160 , according to an embodiment of the invention. The node deployments  160  include example entries  602 ,  604 ,  606 ,  608 ,  610 ,  612 ,  614 ,  616 , and  618 , each of which includes an example node identifier field  630  and number of placements field  632 . The node identifier field  630  identifies a server computer node, such as the computer servers  132  or  134 . The number of placements field  632  specifies the number of the images with average resource requirements represented by the unit workload  158  that are deployable to the server computer node identified by the node identifier  630  in the same entry. That is, the number of placements field  632  identifies the number of average images with an average processor speed requirement and an average memory requirement that can be deployed to the server computer system (identified by the node identifier  630  in the same entry) and whose deployment would not consume more than the available or free resources at that node. 
     Stated another way, the node deployments  160  identifies the count or number of the average images (having the unit workload&#39;s average processor speed requirement and average memory requirement) that can be deployed, installed, and executed at each server computer node. Thus, the server computer nodes  630  have enough free processor speed and free memory to deploy, install, and execute the number  632  of average images in the same entry. The number of placements  632  specifies a count or number of the average images (described by the unit workload  158 ) that can be deployed, installed, and executed on the server (in the same entry) using the free processor speed  332  and free memory  334 , meaning that the number of placements  632  multiplied by the processor speed requirement  524  in the unit workload  158  is less than or equal to the free processor speed  332  of the respective node and the number of placements  632  multiplied by the memory  526  in the unit workload  158  is less than or equal to the free memory  334  of the respective node. The average number of placements  640  is the sum of the number of placements  632  for all server computer nodes (for all entries  602 ,  604 ,  606 ,  608 ,  610 ,  612 ,  614 ,  616 , and  618 ). Thus, the average number of placements  640  indicates the number of the unit workloads  158  (having average resource requirements) that can be deployed (are deployable) using the free resources that are available in all of the server computer nodes. 
       FIG. 7  depicts a block diagram of an example data structure for a deployment history  162 , according to an embodiment of the invention. The deployment history  162  comprises example entries  702 ,  704 ,  706 ,  708 , and  710 , each of which comprises an example user identifier field  730 , an image identifier field  732 , and a count field  734 . The user identifier field  730  identifies a user who requested deployment, installation, configuration, and/or execution of an image from the image library  150  identified by the image identifier field  732  (in the same entry) to any server computer system. The count field  734  identifies a count of the number of times that the image identified by the image identifier  732  in the same entry was requested to be deployed, installed, configured, and/or executed by the user identified by the user identifier  730  (in the same entry) at times prior to the current time. 
       FIG. 8  depicts a block diagram of an example data structure for a unit workload  158 - 2  for a particular specified user, according to an embodiment of the invention. The unit workload  158 - 2  is an example of, and is generically referred to by, the unit workload  158  ( FIG. 1 ). In the example data of  FIG. 8 , the specified user is user A, but the specified user may be any user identified or specified by a command or request. The unit workload  158 - 2  comprises an image identifier field  822 , a processor speed field  824 , a memory field  826 , and a processor architecture field  828 . The image identifier field  822  specifies the images in the image library  150  that are represented by the unit workload  158 - 2 . The processor speed field  824  specifies the weighted average processor speed requirement of the images specified by the image identifier field  822 . The memory field  826  specifies the weighted average memory requirements of the images specified by the image identifier field  822 . The processor architecture field  828  specifies the processor architecture that is required by the images specified by the image identifiers  822 , in order for the images to execute. The weighted averages are weighted in proportion to the number of times (a zero number of times still receives some weight) that a user requested deployment of the images. 
     The unit workload  158 - 2  describes, for one specified user that requested the deployment of all of the images identified by the image identifiers  822 , the weighted average resource requirements (the weighted average required processor speed  824  and the weighted average amount of memory  826  required) of the images identified by the image identifiers  822 . The image identifiers  822  identify images in the image library  150  that are members of the same cloud or that execute on a processor having the same processor architecture. The deployment service  156  calculates the unit workload  158 - 2  from the deployment history  162  for the specified example user A (represented by the example data of the entries  702  and  704  in the deployment history  162  of  FIG. 7 ) and from the resource requirements  154  of the images (represented by the example data in  FIG. 4 ). The deployment service  156  performs this calculation, giving some weight or significance to all the images in the image library  150  that require the processor architecture of a specified cloud (even if not actually deployed by the specified user), and also gives weight or significance to the specified user&#39;s actually deployment of images to the specified cloud. If the specified user has not deployed any images to the specified cloud, then the unit workload  158 - 2  is identical to the unit workload  158 - 1 . But, as the specified user requests the deployment of more images to the specified cloud, the deployment history  162  of the specified user becomes more significant to the calculation that the deployment service  156  performs in creating the unit workload  158 - 2 , which becomes more tailored or specific to the deployment history  162  of the specified user. 
     Using the user A&#39;s example deployment history (illustrated in the entries  702  and  704  of the deployment history  162  of  FIG. 7 , the deployment service  156  performs the following calculations, in order to create the unit workload  158 - 2  for the specified example user A. Image A: 1000 MIPS*8=8000 MIPS; 4 GB*8=32 GB Memory. Image B: 4000 MIPS*1=4000 MIPS; 2 GB*1=2 GB Memory. Image C: 7000 MIPS*1=7000 MIPS; 4 GB*1=4 GB Memory. Image D: 2000 MIPS*2=4000 MIPS; 8 GB*2=16 GB Memory. Image F: 3500 MIPS*1=3500 MIPS; 6 GB*1=6 GB Memory. Total processor speed: 8000+4000+7000+4000+3500=26,500 MIPS. Total memory: 32+2+4+16+6=60 GB Memory. 
     The deployment service  156  uses 8 as a weighting factor for image A because the user A deployed the image A 7 times (entry  702  in  FIG. 7 ) and the deployment service  156  adds 1 to the number of actual number of deployments by the user, in order to give all images with a processor architecture requirement that matches (is identical to) the processor architecture of the specified cloud, regardless of whether actually deployed, some weight or significance in the calculation. The deployment service  156  uses 1 as a weighting factor for image B because the user A deployed the image B zero times (no entry exists in  FIG. 7  for the user A and the image B), and the deployment service  156  adds 1 to the number of actual deployments by the user, in order to give all images, regardless of whether actually deployed, some weight or significance in the calculation. The deployment service  156  uses 1 as a weighting factor for image C because the user A deployed the image C zero times (no entry exists in  FIG. 7  for the user A and the image C) and the deployment service  156  adds 1 to the number of actual deployments by the user. The deployment service  156  uses 2 as a weighting factor for image D because the user A deployed the image D one time (entry  704  in  FIG. 7 ), and the deployment service  156  adds 1 to the number of actual deployments by the user. The deployment service  156  uses 1 as a weighting factor for image F because the user A deployed the image F zero times (no entry exists in  FIG. 7  for the user A and the image F), and the deployment service  156  adds 1 to the number of actual deployments by the user. 
     The total number of deployments=13=8+1+1+2+1. Five out of the total number of deployments are the default weight given to all images regardless of whether or not the user deployed them, and eight of the total number of deployments ( 7  in the entry  702  and  1  in the entry  704  of  FIG. 7 ) are the deployments requested by the user A. The deployment service  156  calculates the unit workload processor speed  824  as the total processor speed divided by the total number of deployments: 26,500 MIPs/13 deployments=2038 MIPs/deployment. The deployment service  156  calculates the unit workload memory  826  to be the total memory amount divided by the total number of deployments: 60 GB/13 deployments=4.6 GB/deployment. 
       FIG. 9  depicts a flowchart of example processing for creating a unit workload and node deployments, according to an embodiment of the invention. Control begins at  900 . Control then continues to block  905  where the deployment service  156  receives a command from a user interface via the user interface device  121  that specifies a target cloud identifier and a specified user or an indication of all users. Control then continues to block  910  where the deployment service  156  requests and receives the servers description  152  from the server computer systems and stores the servers description  152  in the memory  102  of the computer system  100 . Control then continues to block  915  where the deployment service  156  reads the resource requirements  154  from the memory  102 . 
     Control then continues to block  920  where the deployment service  156  determines whether the received command specifies that the work unit  158  is requested to describe the average image deployed by all users. If the determination at block  920  is true, then the received command specifies that the work unit is requested to describe the average image deployed by all users, so control continues to block  925  where the deployment service  156  creates a work unit for all users (e.g., the work unit  158 - 1 ), as further described below with reference to  FIG. 10 . Control then continues to block  930  where the deployment service  156  calculates the node deployments  160 , as further described below with reference to  FIG. 12 . Control then continues to block  935  where the deployment service  156  presents or displays the created work unit  158  and the created node deployments  160  via the user I/O device  121 . Control then continues to block  999  where the logic of  FIG. 9  returns. 
     If the determination at block  920  is false, then the received command specifies that the work unit is requested to describe the average image deployed by a specific user, so control continues to block  940  where the deployment service  156  creates a work unit for the specified user (e.g., the work unit  158 - 2 ), as further described below with reference to  FIG. 11 . Control then continues to block  930  where the deployment service  156  calculates the node deployments  160  using the work unit for the specified user  158 - 2 , as further described below with reference to  FIG. 12 . Control then continues to block  935  where the deployment service  156  presents or displays the calculated work unit  158 - 2  and the node deployments  160 . Control then continues to block  999  where the logic of  FIG. 9  returns. The logic of  FIG. 9  may be invoked any number of times in response to any number of different commands received at block  905 . 
       FIG. 10  depicts a flowchart of example processing for creating a unit workload for all users, according to an embodiment of the invention. Control begins at block  1000 . Control then continues to block  1005  where the deployment service  156  calculates the average of the processor speed requirements  422  for all entries in the resource requirements  154  whose processor architecture matches the processor architecture in the target cloud identified by the target cloud identifier specified by the received command and stores the average processor speed  524  in the unit workload  158 - 1  for all users. Control then continues to block  1010  where the deployment service  156  calculates the average of the memory requirements  424  in all entries in the resource requirements  154  whose processor architecture  426  matches the processor architecture in the target cloud identified by the target cloud identifier specified by the received command and stores the average in the memory requirements  526  in the unit workload  158 - 1  for all users. Control then continues to block  1015  where the deployment service  156  stores the processor architecture of the target cloud identified by the target cloud identifier in the processor architecture  528  in the unit workload  158 - 1  for all users. The deployment service  156  further sets the image identifiers used by the calculations of  FIG. 10  into the image identifiers  522  of the unit workload  158 - 1 . Control then continues to block  1099  where the logic of  FIG. 10  returns. 
       FIG. 11  depicts a flowchart of example processing for creating a unit workload for a specified user who requested deployment of images, according to an embodiment of the invention. Control begins at block  1100 . Control then continues to block  1105  where the deployment service  156  sets the total number of deployments to be zero, sets the total processor speed used by the deployments to be zero, and sets the total memory used by the deployments to be zero. The total number of deployments is a temporary variable in memory or in a register that represents a count of the number of deployments of images requested by the specified user, aggregated across all images. The total number of deployments also includes a default weight given to all images, regardless of whether or not the specified user deployed them. Control then continues to block  1110  where the deployment service  156  sets the current image to be the first image in the resource requirements  154  with a processor architecture requirement  426  that matches the processor architecture  336  that is specified in the entries in the servers description  152  that contain cloud identifiers  338  that match the received target cloud identifier. 
     Control then continues to block  1115  where the deployment service  156  sets the deploy count to be one, which is the default weight given to all images, regardless of whether or not the specified user deployed them. The deploy count is a temporary variable in memory or in a register that represents a count of the number of deployments of the current images requested by the specified user. The deploy count also includes the default weight given to all images, regardless of whether or not the specified user deployed them. Control then continues to block  1120  where the deployment service  156  sets the deploy count to be the deploy count plus the count  734  of the number of times that the user deployed the current image. That is, the deployment service  156  finds the entry in the deployment history  162  with a user identifier  730  that matches the specified user and an image identifier  732  that matches the current image and reads the count  734  from that entry. If no such matching entry exists, the deployment service  156  uses zero for the count  734 . 
     Control then continues to block  1125  where the deployment service  156  sets the total number of deployments to be the total number of deployments plus the deploy count. Thus, the deployment service  156  aggregates the total number of deployments across all images. Control then continues to block  1130  where the deployment service  156  sets the total processor speed used by the deployments to be the total processor speed used by the deployments plus (the processor speed requirement  422  of the current image multiplied by the deploy count). The deployment service  156  finds the processor speed requirement  422  of the current image by comparing the identifier of the current image to the image identifier  420 , finding the entry in the resource requirements  154  whose image identifier  420  matches the identifier of the current image, and reading the processor speed requirement  422  from that entry. 
     Control then continues to block  1135  where the deployment service  156  sets the total memory used by the deployments equal to the total memory used by the deployments plus (the memory requirement  424  of the current image multiplied by the deploy count). The deployment service  156  finds the memory requirement  424  of the current image by comparing the identifier of the current image to the image identifier  420 , finding the entry in the resource requirements  154  whose image identifier  420  matches the identifier of the current image, and reading the memory requirement  424  from that entry. 
     Control then continues to block  1140  where the deployment service  156  sets the current image to be the next image in the resource requirements  154  with a processor architecture requirement  426  that matches the processor architecture  336  that is specified in the entries in the servers description  152  that contain cloud identifiers  338  that match the received target cloud identifier. Control then continues to block  1145  where the deployment service  156  determines whether the current image exists. If the determination at block  1145  is true, then the current image exists and not all images have been processed by the logic of  FIG. 11 , so control returns to block  1115  where the deployment service  156  begins processing the next current image, as previously described above. If the determination at block  1145  is false, then the current image does not exist and all images have been processed by the logic of  FIG. 11 , so control continues to block  1150  where the deployment service  156  sets the unit workload processor speed requirements  824  to be the total processor speed used by the deployments divided by the total number of deployments. The deployment service  156  further sets the unit workload memory requirements  826  to be the total memory used by the deployments divided by the total number of deployments. The deployment service  156  further sets the processor architecture  828  to be the processor architecture  336  that is specified in the entries in the servers description  152  that contain cloud identifiers  338  that match the received target cloud identifier. The deployment service  156  further sets the image identifiers used by the calculations of  FIG. 11  into the image identifiers  822  of the unit workload  158 - 2 . Control then continues to block  1199  where the logic of  FIG. 11  returns. 
       FIG. 12  depicts a flowchart of example processing for calculating the node deployments, according to an embodiment of the invention. Control begins at block  1200 . Control then continues to block  1205  where the deployment service  156  initializes the current node identifier to be the first computer system node identifier in the servers description  152  that has a cloud identifier  338  in the same entry that is equal to the target cloud identifier. Control then continues to block  1210  where the deployment service  156  initializes the count to be zero. The count is an internal or temporary variable in memory or in a register that represents a count of the number of placements of the unit workload  158  that are deployable to a server computer system node. 
     Control then continues to block  1215  where the deployment service  156  determines whether the free processor speed  332  of the current node is greater than the processor speed  524  or  824  in the unit workload  158  multiplied by (the count plus one) and the free memory  334  of the current node is greater than [the memory requirement  526  or  826  of the unit workload  158  multiplied by (the count plus one)]. If the determination at block  1215  is true, then the free processor speed  332  of the current node is greater than the processor speed requirement  524  or  824  in the unit workload  158  multiplied by (the count plus one) and the free memory  334  of the current node is greater than [the memory requirement  526  or  826  of the unit workload  158  multiplied by (the count plus one)], so control continues to block  1220  where the deployment service  156  increments the count by one. Control then returns to block  1215  where the deployment service  156  performs the processing previously described above. 
     The deployment service  156  continues in the loop of blocks  1215  and  1220  until the deployment service  156  determines, at block  1215  that the free processor speed  332  of the current node is less than or equal to the processor speed requirement  524  or  824  in the unit workload  158  multiplied by (the count plus one) or the free memory  334  of the current node is less than or equal to the memory requirement  526  or  826  of the unit workload  158  multiplied by (the count plus one), so control continues to block  1225  where the deployment service  156  saves the current node identifier and the count to the node identifier  630  and the number of placements  632 , respectively in a new entry in the node deployments  160 . Control then continues to block  1230  where the deployment service  156  sets the current node identifier to be the next node identifier in the servers description  152  that has a cloud identifier equal to the identifier of the target cloud. Control then continues to block  1235  where the deployment service  156  determines whether the current node identifier exists, i.e., the deployment service  156  determines whether or not all of the nodes identified by the node identifiers in the servers description  152  have been processed by the loop that starts at block  1210  and ends at block  1235 . If the determination at block  1235  is true, then the current node identifier exists and the current node identified by the current node identifier remains to be processed by the loop, so control returns to block  1210  where the deployment service  156  begins processing the next current node, as previously described above. 
     If the determination at block  1235  is false, then the current node identifier does not exist and all nodes in the servers description  152  have been processed by the loop, so control exits the loop and continues to block  1240  where the deployment service  156  calculates the average number of placements to be the sum of the placements  632  for all nodes in the node deployments  160 . The deployment service  156  stores the average number of the placements to the average number  640  in the node deployments  160 . Control then continues to block  1299  where the logic of  FIG. 12  returns. 
       FIG. 13  depicts a flowchart of example processing for defragmenting deployed images, according to an embodiment of the invention. The defragmenter  164  un-deploys or removes images from the server computer system nodes that cause the free processor speed  332  in the server computer system node to be approximately (within a threshold amount) an integer multiple of the unit workload processor speed  524  or  824  and cause the free memory  334  in the server computer system node to be approximately an integer multiple of the unit workload memory  526  or  826 . For example, the server computer system node B (represented by the entry  304  in the servers description  152  of  FIG. 3 ) has a free processor speed  332  of  4000  MIPs and a free memory amount of 4 GB, which are approximately integer multiples of 3500 MIPs (unit workload processor speed  524 ) and 4.8 GB (unit workload memory  526 ), respectively, so in an embodiment, the defragmenter  164  does not un-deploy any images from the server computer system node B  132 - 2 . 
     As another example, the server computer system node G (represented by the entry  314  in the servers description  152  of  FIG. 3 ) has a free processor speed  332  of 1000 MIPs and a free memory  334  of 2 GB, which are both, in an embodiment, not approximately integer multiples of the unit workload speed  524  and memory  526 , so the defragmenter  164  searches for a combination of images to un-deploy from the computer system node G  132 - 7  that have processor speed requirements  422  and memory requirements  424  ( FIG. 4 ) that respectively total approximately 2500 MIPs (3500−1000) and 2.8 GB (4.8−2). 
     Control begins at block  1300 . Control then continues to block  1305  where the defragmenter  164  sets the current node identifier to be the first node identifier in the servers description  152 . Control then continues to block  1310  where the defragmenter  164  determines whether the free processor speed  332  at the current server computer system node identified by the current node identifier is within a first threshold amount of a first integer multiple of the unit workload processor speed  524  or  824  (the integer multiple of the unit workload processor speed minus the free processor speed is less than or equal to the first threshold amount) and the free memory  334  at the current node is within a second threshold amount of a second integer multiple of the unit workload memory  526  or  826  (the integer multiple of the unit workload memory minus the free memory amount is less than or equal to the second threshold amount). The first integer multiple and the second integer multiple may be identical but are not necessarily identical. In various embodiments, the thresholds are received from a user interface, read from a memory location as predetermined constants, or determined dynamically. 
     If the determination at block  1310  is true, then the free processor speed  332  of the current server computer system node is within a first threshold amount of an integer multiple of the unit workload processor speed requirement  524  or  824  (the integer multiple of the unit workload processor speed minus the free processor speed is less than or equal to the first threshold amount) and the free memory  334  is within a second threshold amount of an integer multiple of the unit workload memory requirement  526  or  826  (the integer multiple of the unit workload memory minus the free memory amount is less than or equal to the second threshold amount), so control continues to block  1315  where the defragmenter  164  sets the current node identifier to be the next node identifier in the servers description  152  and does not designate the current node as a source node and does not remove or un-deploy images from the current node. Control then continues to block  1320  where the defragmenter  164  determines whether the current node identifier exists. If the determination at block  1320  is true, then current node identifier exists and not all node identifiers in the servers description  152  have been processed by the logic of  FIG. 13 , so control returns to block  1310  where the defragmenter  164  begins processing the next current node, as previously described above. 
     If the determination at block  1320  is false, then the current node identifier does not exist, the logic of block  1315  has reached the end of the servers description  152 , and all node identifiers in the servers description  152  have been processed by the logic of  FIG. 13 , so control continues to block  1399  where the logic of  FIG. 13  returns. If the determination at block  1310  is false, then the free processor speed  332  of the current server computer system node is not within the first threshold amount of an integer multiple of the unit workload processor speed  524  or  824  (the integer multiple of the unit workload processor speed minus the free processor speed is greater than the first threshold amount) or the free memory  334  is not within a second threshold amount of an integer multiple of the unit workload memory  526  or  826  (the integer multiple of the unit workload memory requirement minus the free memory amount is greater than the second threshold amount), so control continues to block  1325  where the defragmenter  164  searches for a combination of images deployed at the current node identified by the current node identifier that have processor speed requirements  422  and memory requirements  424  whose respective sums are within third and fourth threshold amounts, respectively, of the difference between the multiple of the unit workload processor speed  524  or  824  and the multiple of the free memory  526  or  826 , respectively. That is, the defragmenter  164  searches for a combination of images deployed at the current node, where the multiple of the unit workload processor speed requirement  524  or  824  minus the sum of the processor speed requirements  422  of the combination of images deployed at the current node is less than or equal to a third threshold amount and a multiple of the unit workload memory requirement  526  or  826  minus the sum of the memory requirements  424  of the combination of images deployed at the current node is less than or equal to a fourth threshold amount. 
     Control then continues to block  1330  where the defragmenter  164  determines whether a combination of the images was found that meets the search criteria of block  1325 . If the determination at block  1330  is true, then the defragmenter  164  found a combination of images deployed at the current node identified by the current node identifier that have processor speed requirements and memory requirements whose respective sums are within third and fourth threshold amounts, respectively, of the difference between the multiple of the unit workload processor speed and the multiple of the free memory, so control continues to block  1335  where the defragmenter  164  designates the current server computer system node as a source node and the found image(s) as source image(s), which are candidates to be moved to another server computer system node in the same cloud. Control then continues to block  1405  of  FIG. 14  where the defragmenter  164  searches for a destination node in the same cloud as the source node with a free processor speed and a free memory amount that are greater than or equal to the processor speed requirement and memory requirement of the source image(s), respectively, such that the free processor speed of the destination node minus the sum of the processor requirements of the source image is within the first threshold amount of an integer multiple of the unit workload processor speed and the free memory amount of the destination node minus the sum of the memory requirements of the source image is within the second threshold amount of an integer multiple of the unit workload memory amount. That is, the defragmenter  164  searches for a destination node in the same cloud as the source node with a free processor speed and a free memory amount that are greater than or equal to the processor speed requirement and memory requirement of the source image(s), respectively, such that an integer multiple of the unit workload processor speed minus the free processor speed of the destination node minus the sum of the processor requirements of the source image is less than or equal to the first threshold amount and an integer multiple of the unit workload memory amount minus the free memory amount of the destination node minus the sum of the memory requirements of the source image is less than or equal to the second threshold amount. 
     Control then continues to block  1410  where the defragmenter  164  determines whether the search done by the processing illustrated in block  1405  found a destination node. If the determination of block  1410  is true, then the search found a destination node, so control continues to block  1415  where the defragmenter  164  un-deploys, uninstalls, deletes, and/or stops the execution of the found image or combination of images from the current node. Control then continues to block  1420  where the defragmenter  164  deploys, stores, configures, and/or installs the found source image(s) to the destination node, where the found source image(s) begin executing. Control then returns to block  1315  of  FIG. 13 , where the defragmenter  164  sets the current node identifier to be the next node identifier in the servers description  152 , as previously described above. If the determination of block  1410  is false, then the search did not find a destination node, so the defragmenter refrains from un-deploying the source image(s) from the source node and refrains from deploying the source image(s) to another node, so control returns to block  1315  of  FIG. 13 , as previously described above. 
     If the determination at block  1330  is false, then the defragmenter  164  did not find a combination of images deployed at the current node identified by the current node identifier that have processor speed requirements and memory requirements whose respective sums are within third and fourth threshold amounts, respectively, of the difference between the multiple of the unit workload processor speed and the multiple of the free memory, so control returns to block  1315  where the defragmenter  164  sets the current node identifier to be the next node identifier in the servers description  152 , as previously described above. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of the stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. In the previous detailed description of exemplary embodiments of the invention, reference was made to the accompanying drawings (where like numbers represent like elements), which form a part hereof, and in which is shown by way of illustration specific exemplary embodiments in which the invention may be practiced. These embodiments were described in sufficient detail to enable those skilled in the art to practice the invention, but other embodiments may be utilized and logical, mechanical, electrical, and other changes may be made without departing from the scope of the present invention. In the previous description, numerous specific details were set forth to provide a thorough understanding of embodiments of the invention. But, embodiments of the invention may be practiced without these specific details. In other instances, well-known circuits, structures, and techniques have not been shown in detail in order not to obscure embodiments of the invention. Different instances of the word “embodiment” as used within this specification do not necessarily refer to the same embodiment, but they may. Any data and data structures illustrated or described herein are examples only, and in other embodiments, different amounts of data, types of data, fields, numbers and types of fields, field names, numbers and types of rows, records, entries, or organizations of data may be used. In addition, any data may be combined with logic, so that a separate data structure is not necessary. The previous detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims.