Abstract:
The embodiments contemplate a system and method for a provisioning, retirement and configuration of virtual machines. A predefined policy may include a desired target state of the virtual machines, as well as an action to initiate in order to reach the desired state. The action may be initiated if the state varies from the desired level by a predetermined amount or percentage over a predetermined period of time. Data from the virtual machines is analyzed to determine if the desired state of the virtual machines is satisfied. The analysis may be continuous or periodic. If it is determined that the desired state is not satisfied, then predefined actions are performed until the desired state is attained. The predefined actions may be the removal or addition of one or more virtual machines or other actions necessary to reach the desired state.

Description:
BACKGROUND 
     A virtual machine is a software construct or the like operating on a computing device or the like for the purpose of emulating a hardware system. Typically, although not necessarily, the virtual machine is an application or the like and is employed on the computing device to host a user application or the like while at the same time isolating such user application from such computing device or from other applications on such computing device. A different variation of a virtual machine may, for example, be written for each of a plurality of different computing devices so that any user application written for the virtual machine can be operated on any of the different computing devices. Thus, a different variation of the user application for each different computing device is not needed. 
     New architectures for computing devices and new software now allow a single computing device to instantiate and run a plurality of partitions, each of which can be employed to instantiate a virtual machine to in turn host an instance of an operating system upon which one or more applications may be instantiated. Typically, although not necessarily, the computing device includes a virtualization layer with a virtual machine monitor or the like that acts as an overseer application or ‘hypervisor’, where the virtualization layer oversees and/or otherwise manages supervisory aspects of each virtual machine and acts as a possible link between each virtual machine and the world outside of such virtual machine. 
     Among other things, a particular virtual machine on a computing device may require access to a resource associated with the computing device. As may be appreciated, such resource may be any sort of resource that can be associated with a computing device. For example, the resource may be a storage device to store and retrieve data, and generally for any purpose that a storage device would be employed. Likewise, the resource may be any other asset such as a network, a printer, a scanner, a network drive, a virtual drive, a server, a software application, and the like. Accordingly, whatever the resource may be, the virtual machine may in fact be provided with access to services provided by such resource. 
     Virtual machines are an expensive system resource as they may occupy or consume large amounts of system resources, such as memory, disk space, and/or processor cycles. Furthermore, often virtual machines run and consume system resources while not being utilized. A virtual machine may, for example, inefficiently maintain access over a particular resource that it is not even utilizing. Or a user of the system may inadvertently leave the virtual machine running after use of the virtual machine has ceased. 
     Conventional and current monitoring systems may track the usage of system objects and accordingly take appropriate measures upon the determination of an inactive object. However, such monitoring systems may not accurately detect the usage of one or more virtual machines. For example, a guest operating system of a virtual machine may be performing maintenance tasks, downloading patches, or performing other operations that may not be related to a primary goal of the guest operating system. Such operations in the form of, for example, process usage or host statistics may inaccurately serve as an indication that the virtual machine is active when in fact the virtual machine may not be actively performing its primary goal. 
     In addition to determining if a virtual machine is active, a mechanism for the provisioning of virtual machines by a system administrator in order to achieve and maintain a desired state of the system, such as a target usage or threshold value, is not currently available. Such a mechanism may employ a policy administrator to set certain policy requirements, such as a predetermined target usage or threshold level, in order to attain a desired state. 
     Therefore, a mechanism and system to detect a state of a virtual machine and enforce a set of policies, which in turn may ensure that system resources are not being wasted or mismanaged, are desired. 
     SUMMARY 
     A virtual machine provisioning method and system operate to allocate and adjust the virtual machines according to a predefined policy, which may be created by a policy administrator. Data is collected from the virtual machines and other computing devices, and the type of data collected is dictated by the policy. The policy may also include one or more target levels or thresholds or usages, and a determination is made to ascertain if the target is being attained. When the target is not attained, the allocation of virtual machines is adjusted until the target is reached. The allocation may also be part of the policy defined by the system administrator. 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing summary and the following detailed description are better understood when read in conjunction with the appended drawings. Exemplary embodiments are shown in the drawings, however it is understood that the embodiments are not limited to the specific methods and instrumentalities depicted therein. In the drawings: 
         FIG. 1  is a block diagram representing an exemplary computing device in which the present invention may be implemented; 
         FIG. 2  is a block diagram representing an exemplary network environment having a variety of computing devices in which the present invention may be implemented; 
         FIG. 3  is a block diagram representing a virtual machine provisioning system in accordance with embodiments of the present invention; 
         FIG. 4  is a block diagram representing a monitoring agent in accordance with one embodiment of the present invention; 
         FIG. 5  is a block diagram representing an enforcement agent in accordance with one embodiment of the present invention; and 
         FIG. 6  is a flow diagram illustrating a virtual machine provisioning method in accordance with one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Computer Environment 
     With reference to  FIG. 1 , an exemplary system for implementing the invention includes a general purpose computing device in the form of a computer  110 . Components of computer  110  may include, but are not limited to, a processing unit  120 , a system memory  130 , and a system bus  121  that couples various system components including the system memory to the processing unit  120 . The system bus  121  may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus (also known as Mezzanine bus). 
     The computer  110  typically includes a variety of computer readable media. Computer readable media can be any available media that can be accessed by the computer  110  and includes both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computer readable media may comprise computer storage media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by the computer  110 . Communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared and other wireless media. Combinations of any of the above should also be included within the scope of computer readable media. 
     The system memory  130  includes computer storage media in the form of volatile and/or nonvolatile memory such as ROM  131  and RAM  132 . A basic input/output system  133  (BIOS), containing the basic routines that help to transfer information between elements within the computer  110 , such as during start-up, is typically stored in ROM  131 . RAM  132  typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by the processing unit  120 . By way of example, and not limitation,  FIG. 1  illustrates operating system  134 , application programs  135 , other program modules  136 , and program data  137 . 
     The computer  110  may also include other removable/non-removable, volatile/nonvolatile computer storage media. By way of example only,  FIG. 1  illustrates a hard disk drive  141  that reads from or writes to non-removable, nonvolatile magnetic media, a magnetic disk drive  151  that reads from or writes to a removable, nonvolatile magnetic disk  152 , and an optical disk drive  155  that reads from or writes to a removable, nonvolatile optical disk  156 , such as a CD-ROM or other optical media. Other removable/non-removable, volatile/nonvolatile computer storage media that can be used in the exemplary operating environment include, but are not limited to, magnetic tape cassettes, flash memory cards, digital versatile disks, digital video tape, solid state RAM, solid state ROM, and the like. The hard disk drive  141  is typically connected to the system bus  121  through a non-removable memory interface such as an interface  140 , and the magnetic disk drive  151  and the optical disk drive  155  are typically connected to the system bus  121  by a removable memory interface, such as an interface  150 . 
     The drives and their associated computer storage media, discussed above and illustrated in  FIG. 1 , provide storage of computer readable instructions, data structures, components, program modules and other data for the computer  110 . In  FIG. 1 , for example, the hard disk drive  141  is illustrated as storing operating system  144 , application programs  145 , other program modules  146 , and program data  147 . Note that these components can either be the same as or different from operating system  134 , application programs  135 , other program modules  136 , and program data  137 . Operating system  144 , application programs  145 , other program modules  146 , and program data  147  are given different numbers here to illustrate that, at a minimum, they are different copies. A user may enter commands and information into the computer  110  through input devices such as a keyboard  162  and a pointing device  161 , commonly referred to as a mouse, trackball or touch pad. Other input devices (not shown) may include a microphone, joystick, game pad, satellite dish, scanner, or the like. These and other input devices are often connected to the processing unit  120  through a user input interface  160  that is coupled to the system bus, but may be connected by other interface and bus structures, such as a parallel port, game port or a universal serial bus (USB). A monitor  191  or other type of display device is also connected to the system bus  121  via an interface, such as a video interface  190 . In addition to the monitor, computers may also include other peripheral output devices such as speakers  197  and a printer  196 , which may be connected through an output peripheral interface  195 . 
     The computer  110  may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer  180 . The remote computer  180  may be a personal computer, a server, a router, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above relative to the computer  110 , although only a memory storage device  181  has been illustrated in  FIG. 1 . The logical connections depicted include a local area network (LAN)  171  and a wide area network (WAN)  173 , but may also include other networks. Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets and the Internet. 
     When used in a LAN networking environment, the computer  110  is connected to the LAN  171  through a network interface or adapter  170 . When used in a WAN networking environment, the computer  110  typically includes a modem  172  or other means for establishing communications over the WAN  173 , such as the Internet. The modem  172 , which may be internal or external, may be connected to the system bus  121  via the user input interface  160 , or other appropriate mechanism. In a networked environment, program modules depicted relative to the computer  110 , or portions thereof, may be stored in the remote memory storage device. By way of example, and not limitation,  FIG. 1  illustrates remote application programs  185  as residing on memory device  181 . It will be appreciated that the network connections shown are exemplary and other means of establishing a communications link between the computers may be used. 
     All or portions of the methods of the present invention described above may be embodied in hardware, software, or a combination of both. When embodied in software, the methods of the present invention, or certain aspects or portions thereof, may be embodied in the form of program code that when executed by a computing system cause the computing system to perform the methods of the present invention. This program code may be stored on any computer-readable medium, as that term is defined above. 
     One of ordinary skill in the art can appreciate that a computer  110  or other client device can be deployed as part of a computer network. In this regard, the present invention pertains to any computer system having any number of memory or storage units, and any number of applications and processes occurring across any number of storage units or volumes. The present invention may apply to an environment with server computers and client computers deployed in a network environment, having remote or local storage. The present invention may also apply to a standalone computing device, having programming language functionality, interpretation and execution capabilities. 
     Distributed computing facilitates sharing of computer resources and services by direct exchange between computing devices and systems. These resources and services include the exchange of information, cache storage, and disk storage for files. Distributed computing takes advantage of network connectivity, allowing clients to leverage their collective power to benefit the entire enterprise. In this regard, a variety of devices may have applications, objects or resources that may interact to implicate authentication techniques of the present invention for trusted graphics pipeline(s). 
       FIG. 2  provides a schematic diagram of an exemplary networked or distributed computing environment. The distributed computing environment comprises computing objects  10   a ,  10   b , etc. and computing objects or devices  110   a ,  110   b ,  110   c , etc. These objects may comprise programs, methods, data stores, programmable logic, etc. The objects may comprise portions of the same or different devices such as PDAs, televisions, MP3 players, televisions, personal computers, etc. Each object can communicate with another object by way of the communications network  14 . This network may itself comprise other computing objects and computing devices that provide services to the system of  FIG. 2 . In accordance with an aspect of the invention, each object  10  or  110  may contain an application that might request the authentication techniques of the present invention for trusted graphics pipeline(s). 
     It can also be appreciated that an object, such as  110   c , may be hosted on another computing device  10  or  110 . Thus, although the physical environment depicted may show the connected devices as computers, such illustration is merely exemplary and the physical environment may alternatively be depicted or described comprising various digital devices such as PDAs, televisions, MP3 players, etc., software objects such as interfaces, COM objects and the like. 
     There are a variety of systems, components, and network configurations that support distributed computing environments. For example, computing systems may be connected together by wire-line or wireless systems, by local networks or widely distributed networks. Currently, many of the networks are coupled to the Internet, which provides the infrastructure for widely distributed computing and encompasses many different networks. 
     In home networking environments, there are at least four disparate network transport media that may each support a unique protocol such as Power line, data (both wireless and wired), voice (e.g., telephone) and entertainment media. Most home control devices such as light switches and appliances may use power line for connectivity. Data Services may enter the home as broadband (e.g., either DSL or Cable modem) and are accessible within the home using either wireless (e.g., HomeRF or 802.11b) or wired (e.g., Home PNA, Cat 5, even power line) connectivity. Voice traffic may enter the home either as wired (e.g., Cat 3) or wireless (e.g., cell phones) and may be distributed within the home using Cat 3 wiring. Entertainment media may enter the home either through satellite or cable and is typically distributed in the home using coaxial cable. IEEE 1394 and DVI are also emerging as digital interconnects for clusters of media devices. All of these network environments and others that may emerge as protocol standards may be interconnected to form an intranet that may be connected to the outside world by way of the Internet. In short, a variety of disparate sources exist for the storage and transmission of data, and consequently, moving forward, computing devices will require ways of protecting content at all portions of the data processing pipeline. 
     The ‘Internet’ commonly refers to the collection of networks and gateways that utilize the TCP/IP suite of protocols, which are well-known in the art of computer networking. TCP/IP is an acronym for “Transmission Control Protocol/Internet Protocol.” The Internet can be described as a system of geographically distributed remote computer networks interconnected by computers processing networking protocols that allow users to interact and share information over the networks. Because of such wide-spread information sharing, remote networks such as the Internet have thus far generally evolved into an open system for which developers can design software applications for performing specialized operations or services, essentially without restriction. 
     Thus, the network infrastructure enables a host of network topologies such as client/server, peer-to-peer, or hybrid architectures. The “client” is a member of a class or group that uses the services of another class or group to which it is not related. Thus, in computing, a client is a process, i.e., roughly a set of instructions or tasks, that requests a service provided by another program. The client process utilizes the requested service without having to “know” any working details about the other program or the service itself. In a client/server architecture, particularly a networked system, a client is usually a computer that accesses shared network resources provided by another computer e.g., a server. In the example of  FIG. 2 , computers  110   a ,  110   b , etc. can be thought of as clients and computer  10   a ,  10   b , etc. can be thought of as the server where server  10   a ,  10   b , etc. maintains the data that is then replicated in the client computers  110   a ,  110   b , etc. 
     A server is typically a remote computer system accessible over a remote network such as the Internet. The client process may be active in a first computer system, and the server process may be active in a second computer system, communicating with one another over a communications medium, thus providing distributed functionality and allowing multiple clients to take advantage of the information-gathering capabilities of the server. 
     Client and server communicate with one another utilizing the functionality provided by a protocol layer. For example, Hypertext-Transfer Protocol (HTTP) is a common protocol that is used in conjunction with the World Wide Web (WWW). Typically, a computer network address such as a Universal Resource Locator (URL) or an Internet Protocol (IP) address is used to identify the server or client computers to each other. The network address can be referred to as a Universal Resource Locator address. For example, communication can be provided over a communications medium. In particular, the client and server may be coupled to one another via TCP/IP connections for high-capacity communication. 
     Thus,  FIG. 2  illustrates an exemplary networked or distributed environment, with a server in communication with client computers via a network/bus, in which the present invention may be employed. In more detail, a number of servers  10   a ,  10   b , etc., are interconnected via a communications network/bus  14 , which may be a LAN, WAN, intranet, the Internet, etc., with a number of client or remote computing devices  110   a ,  110   b ,  110   c ,  110   d ,  110   e , etc., such as a portable computer, handheld computer, thin client, networked appliance, or other device, such as a VCR, TV, oven, light, heater and the like in accordance with the present invention. It is thus contemplated that the present invention may apply to any computing device in connection with which it is desirable to process, store or render secure content from a trusted source, and to any computing device with which it is desirable to render high performance graphics generated by a virtual machine. 
     In a network environment in which the communications network/bus  14  is the Internet, for example, the servers  10  can be Web servers with which the clients  110   a ,  110   b ,  110   c ,  110   d ,  110   e , etc. communicate via any of a number of known protocols such as HTTP. Servers  10  may also serve as clients  110 , as may be characteristic of a distributed computing environment. Communications may be wired or wireless, where appropriate. Client devices  110  may or may not communicate via communications network/bus  14 , and may have independent communications associated therewith. For example, in the case of a TV or VCR, there may or may not be a networked aspect to the control thereof. Each client computer  110  and server computer  10  may be equipped with various application program modules or objects  135  and with connections or access to various types of storage elements or objects, across which files may be stored or to which portion(s) of files may be downloaded or migrated. Thus, the present invention can be utilized in a computer network environment having client computers  110   a ,  110   b , etc. that can access and interact with a computer network/bus  14  and server computers  10   a ,  10   b , etc. that may interact with client computers  110   a ,  110   b , etc. and other devices  111  and databases  20 . 
     Virtual Machine Provisioning: Administrator-Based 
     A mechanism for the provisioning of virtual machines is desired in order to achieve and maintain a predetermined state or requirement of a system of virtual machines. A virtual machine provisioning system  300  to achieve this goal is illustrated in  FIG. 3 . Virtual machines  310  are connected to a monitoring agent  320 .  FIG. 3  illustrates three virtual machines  310  ( 310   a ,  310   b , and  310   c ), although the number of virtual machines is not so limited and more or fewer virtual machines  310  may form part of the virtual machine provisioning system  300 . The monitoring agent  320  is responsible for collecting data from the virtual machines  310 . The monitoring agent  320  may also collect data from a virtual server host  350 , connected to virtual machines  310 , and/or from a computing device or system  360 , also connected to virtual machines  310 . The computing device or system  360  may include, for example, a network router, load balancing hardware, a firewall, a software management system, and/or any combination thereof. The collected data may be used to determine a state of the virtual machines  310  and to determine if their state or that of the system, which may be a combination of virtual machines  310  from multiple servers, is at a predetermined state. The provisioning mechanism is employed, as described in further detail below, if the state of the virtual machines  310  is not at or near the predetermined state. 
     The monitoring agent  320  receives instructions or system policies from a policy administrator  340  that may be responsible for creating the system policies. The system policies may include various system parameters or requirements needed to attain a desired system goal or system functionality. For example, in a server environment where the virtual machines  310  may act as individual system servers, the policy administrator  340  may define network activity. For example, network activity may include a group of usage policies based upon web activity of the servers. The policies may include a target usage of a particular number of web pages per minute per server. A target server count, or number of servers to achieve the target usage, may also be dictated as part of the system policies. Other system policies in the server example may include but are not limited to: an upper usage limit; a lower usage limit; a number of servers to remove upon detection of low usage; a number of servers to add upon detection of high usage; and a usage threshold indicating the need to add or remove a server. Usage may refer to network bandwidth, CPU, memory, disk utilization, and/or any combination thereof. The usage policies identified herein are just one set of examples of system policies. Other system policies or groups of system policies may be created and applied. Moreover, usage may be defined based upon the particular function or goal of the policy. For example, usage may be pages/minute, bytes/second, selects/hour, and/or inserts/day. 
     The policy administrator  340 , upon creating the system polices, may relay this information to the monitoring agent  320 . The monitoring agent  320  then uses the received system policies in order to obtain relevant information from the virtual machines  310 , from the virtual server host  350 , and/or from the computing device/system  360 . For example with respect to the server situation described above, the system policies include various web usage policies. The monitoring agent  320  may accordingly monitor and collect web usage, in for example web pages per minute per server, from each of the virtual machines  310  such as the virtual machines  310   a ,  310   b , and  310   c . Thus, the monitoring agent  320  may collect information from the virtual machines  310  and other monitoring devices or systems, such as the virtual server host  350  and the computing device/system  360 , that is related to the system policies defined by the policy administrator  340 . 
     The monitoring agent  320 , in addition to collecting information from the virtual machines  310 , directly or indirectly, and receiving system policy information from the policy administrator  340 , may be responsible for determining a state of the system  300  based upon the collected data and the system policies. The system of virtual machines  310  may be in a healthy or an unhealthy state. The state determination may be made by a comparison operation in which the collected data is compared against the target usages. If the collected data is higher or lower than the target usage, the system may be said to be unhealthy. An unhealthy state may be defined as a deviation from the target usage over a period of time. An unhealthy state may, for example, be a +/−10% deviation from the target usage for a 24 hour period. Or an unhealthy state may be a +10% deviation from the target usage for a 15 minute period or a −5% deviation from the target usage for a 24 hour period. The state parameters may be defined by the policy administrator  340  according to previously collected data. 
     In addition to state parameters, the policy administrator  340  may also define as part of the system policies the action or actions to be taken when it is determined that the system is in an unhealthy state and has violated the set, defined policies. Such an action may be referred to as a violation action and may be a configurable parameter. Violation actions may include but are not limited to the following: stop a virtual machine  310 ; pause a virtual machine  310  for a predetermined amount of time; delete a virtual machine  310 ; add a virtual machine  310 ; archive a virtual machine  310 ; send a notification to an owner of a virtual machine  310  and/or the policy administrator  340 ; add memory to a virtual machine  310 ; add a virtual processor to a virtual machine  310 ; dedicate more CPU to a virtual machine  310 ; dedicate less CPU to a virtual machine  310 ; save a state of a virtual machine  310 ; and quarantine a virtual machine  310 . If the violation action includes sending a message to an owner of a virtual machine  310  and/or the policy administrator  340 , then the message may be sent by, but is not limited to, email, pager, or cell phone message. 
     The system may employ one or more strategies to comply with policy requirements. One such strategy is to migrate virtual machines  310  to other host servers to allow them to increase their capacity. Another strategy may include migrating all or some of the other virtual machines  310  from this host such that a particular virtual machine  310  can indirectly utilize the freed resources. Such strategies may be especially useful when dealing with CPU thresholds. 
     The policy, which may be defined by the policy administrator  340 , may contain different actions for various levels or thresholds of violation. For example if the violation is within 10% of its target, one particular action may be performed, as specified by the policy. However, for a more extreme violation, such as a 30% deviation from a target, a more drastic action may accordingly be performed. 
     An enforcement agent  330  is responsible for performing a violation action as defined by the policy administrator  340 . The enforcement agent  330  and the monitoring agent  320 , although shown as separate components in  FIG. 3 , may be one component without departing from the spirit and scope of the described embodiments. The policy administrator  340  provides the violation action to the enforcement agent  330 . The violation action may be a portion of the system policies. The monitoring agent  320  provides an indication to the enforcement agent  330  if an unhealthy state, as defined through the system policies by the policy administrator  340 , is reached. Upon such an indication, the enforcement agent  330  may then take appropriate action based upon the defined violation action. 
     For example, suppose that the policy administrator  340  defines system policies as a target usage of a web server at 1,000 pages per minute per web server for a target of 10 virtual machines  310 . The target usage is, in this example, the monitored variable and is used to determine the state (healthy or unhealthy) of the system. The virtual machines  310  provide their respective usage in number of pagers per minute to the monitoring agent  320 . Further suppose that the policy administrator  340  defines an unhealthy state as +/−10% change in usage over a 24 hour time period. If the monitoring agent  320  detects in virtual machine  310   a +/−10% change in usage over a 24 hour time period, then the monitoring agent  320  relays such detection to the enforcement agent  330  to take appropriate action. Suppose that the policy administrator  340  defines a violation action as deleting a virtual machine if the usage for the particular virtual machine is −10% below 1,000 pages per minute and adding a virtual machine if the usage is +10% above 1,000 pages per minute. The policy administrator  340  communicates to the enforcement agent  330  the action to take when the enforcement agent  330  receives an indication from the monitoring agent  320 . The enforcement agent  330  may need to take action on other devices to remedy the violation. For example, the enforcement agent  330  may need to reconfigure a load and balancing hardware to inform it about the new machine being added or removed from the system and become active or reconfigure a firewall to allow traffic to flow to the new machine. 
       FIG. 4  is a block diagram of a monitoring agent  320  according to an embodiment of the invention. The monitoring agent  320  includes several means, devices, software, and/or hardware for performing functions, including a data collection component  410 , a policy component  420 , and a state determination component  430 , which may operate to obtain information from a plurality of virtual machines  310  and use the obtained information to determine a state of the system of virtual machines  310 . 
     The data collection component  410  operates to collect information from the virtual machines  310 . The information may be continuously collected or may be collected at predetermined intervals as specified by the policy administrator  340 . The data collection component  410  may reside on a different server and may operate to collect information from more than one server. The data collection component  410  as a remote component  410   a  is also shown in  FIG. 4 . The information to be collected by the data collection component  410  is dictated by the policy administrator  340  according to policy considerations deemed necessary by the policy administrator  340 . The policy component  420  operates to receive the system policies from the policy administrator  340  and also operates to provide this information to the data collection component  410 . In this manner, through the policy component  420  and the data collection component  410 , the monitoring agent  320  is made aware of the system policies and is informed as to the type of information to collect. 
     The state determination component  430  of the monitoring agent  320  operates to determine the state of the virtual machines  310 . A desired state is defined as part of the system policies made by the policy administrator  340 . If the desired state is attained, the virtual machines are in a healthy state. If the desired state is not attained, an unhealthy state occurs. Alternatively and in addition to a healthy state, a warning state may exist where, for example, the unhealthy state is close to being reached. The warning state may be defined as a predetermined deviation from the unhealthy state. If a warning state is reached, the state of the virtual machines  310  may still be in a healthy state with the warning state serving as a level of indication of the state of the virtual machines  310 . 
     The state determination component  430  uses the system policy information, which is obtained from the policy component  420 , and the information collected from the virtual machines  310  by the data collection component  410  to determine the state of the virtual machines  310 . Additionally, upon determination of a warning state, as defined by the policy administrator  340  and obtained from the policy component  420 , the state determination component  430  may perform a warning action. The warning action may include, but is not limited to, providing a notification to an owner of a virtual machine  310  and/or the policy administrator  340 . 
     The policy administrator  340  may create a policy that is associated with many resources for which one or more violation logics are defined. For each violation logic, one or more thresholds and resulting actions/notifications may be attached. Violations may also define the state of the resource, giving the administrator  340  the option to create one or more states for a resource (i.e. Warning, Healthy, Error state). 
       FIG. 5  is a block diagram of an enforcement agent  330  according to an embodiment of the invention. The enforcement agent  330  includes several means, devices, software, and/or hardware for performing functions, including an indication component  510 , a policy component  520 , and an action component  530 , which operate to take appropriate action as dictated by the policy administrator  340  in order to adjust resources, such as the allocation of virtual machines  310  for example. The adjustment of resources is performed to achieve a healthy state as defined by the policy administrator  340 . The achievement of a healthy state may indicate that the requirements for a given resource are met. 
     The indication component  510  provides an indication of an unhealthy state. The indication component  510  may receive warning of an unhealthy state from the state determination component  430  of the monitoring agent  320 . Upon notification of an unhealthy state, the indication component  510  relays the indication to the action component  530 . The action component  530  is responsible for performing an operation to alleviate the unhealthy state. The action component  530  of the enforcement agent  330  performs a violation action as defined in the system policies by the policy administrator  340 . The action component  530  is informed of the violation action to be performed by the policy component  520 . 
     A virtual machine provisioning method is described in relation to the flow chart of  FIG. 6 . At  610 , system policy requirements are obtained. The system policies may include system parameters or requirements needed for example to attain a desired system goal, such as target usages, and a violation action to be taken when the virtual machines  310  are not in a healthy state. The system policies are provided to the monitoring agent  320  and the enforcement agent  330  by the policy administrator  340 . The monitoring agent  320  may receive the system parameters or requirements, while the enforcement agent  330  may receive the violation action to perform upon notification that the virtual machines  310  are in an unhealthy state. 
     At  620 , relevant data is collected. The relevant data may be collected by the monitoring agent  320  from the virtual machines  310  or from other computing devices or systems, such as computing device/system  360 . Data may be collected from one virtual machine  310  such as virtual machine  310   a  or multiple virtual machines  310  such as  310   b  and  310   c . The interval at which data is collected for each virtual machine  310  or device  360  is also configurable by policy or other means. The system may have a predefined set of policies/violations for common scenarios/workloads and devices. The relevant data may be determined based upon the system policies. At  630 , a state of the virtual machines  310  is determined. The determination may be made by the monitoring agent  320  by comparing the collected data to the system policies. If for example the collected data differs from a preferred system parameter by more or less than a predetermined amount, then the monitoring agent  320  may determine that the virtual machines  310  are in an unhealthy state. 
     If, at  640 , it is determined that the virtual machines  310  are in a healthy state, then the virtual machine provisioning method may return to  630  to continue the operation of determining the state of the virtual machines  310 . The method may proceed in this manner until the virtual machines  310  leave a healthy state and require provisioning to return to the healthy state. 
     At  642 , optionally following a determination that the virtual machines  310  are in a healthy state, a determination may be made to ascertain if a warning state exists. While in a healthy state, the warning state may indicate that the system of virtual machines  310  is close to an unhealthy state. The warning state may be defined by the policy administrator  340  and may include a predetermined deviation from the defined unhealthy state. At  644 , if a warning state does exist, then a warning action is performed by, for example, the state determination component  430 . 
     If instead at  640 , it is determined by the state determination component  430  that the virtual machines  310  are in an unhealthy state, as described in more detail above, then the method may continue to  650 . At  650 , the violation action, which may be part of the system policies as defined by the policy administrator  340 , is examined by the action component  530  to determine if the action requires an addition or removal of a virtual machine  310 . Such an action may be warranted in a server situation where the virtual machines  310  act as servers and the usage in web pages per minute per server is monitored. 
     If the violation action does not specify the addition or removal of a virtual machine  310 , then the specified violation action is performed at  660  by the action component  530 . If instead the specified action does indicate that the addition or removal of a virtual machine  310  should be performed, then at  670  a target usage determination is made by a consultation between the policy administrator  340  and the policy component  420 . If it is determined by the state determination component  430  determined at  670  that the current usage of the virtual machines  310  is below the target usage, then the method proceeds to  680 , where a virtual machine  310  is removed by the action component  530 . The removal of a virtual machine  310  assists in distributing the usage among the remaining virtual machines  310  so that the virtual machines  310  may be used more efficiently. The need to remove a virtual machine  310  may indicate that the virtual machines  310  can handle a larger amount of work and that one or more of the virtual machines  310  is not necessary. 
     Alternatively, if it is determined at  670  by the action component  530  that the current usage of the virtual machines  310  is not below the target usage, then the method proceeds to  690  where a virtual machine  310  is added. If the current usage exceeds the target usage, this may serve as in indication that the virtual machines  310  are handling too much work. An addition of a virtual machine  310  helps to relieve some of this excess. 
     After a violation action is performed at  660  or a virtual machine  310  has been removed or added at  680  or  690 , respectively, by the action component  530 , the provisioning method proceeds to  630  to again determine a state of the virtual machines  310 . This may ensure that the state is continually monitored so that appropriate provisions are made. Alternatively, the state may be monitored after a predetermined time period has elapsed. 
     CONCLUSION 
     In conclusion, the present invention employs a policy that specifies a requirement such as a system goal or preferred level of service with regard to the virtual machine or machines  310 . The policy also specifies an input from the virtual machine or machines  310  and computing devices or systems, such as computing device/system  360 , to be collected by the monitoring agent  320 . The policy further specifies an action with regard to the virtual machine or machines  310  to be taken by the enforcement agent  330  if the specified requirement is violated as determined according to the input by the monitoring agent  320 . 
     As can be appreciated, the disclosed embodiments may be implemented as a whole or in part in one or more computing systems or devices.  FIG. 1  illustrates the functional components of one example of a computing system  100  in which aspects may be embodied or practiced. As used herein, the terms “computing system,” “computer system,” and “computer” refer to any machine, system or device that comprises a processor capable of executing or otherwise processing program code and/or data. Examples of computing systems include, without any intended limitation, personal computers (PCs), minicomputers, mainframe computers, thin clients, network PCs, servers, workstations, laptop computers, hand-held computers, programmable consumer electronics, multimedia consoles, game consoles, satellite receivers, set-top boxes, automated teller machines, arcade games, mobile telephones, personal digital assistants (PDAs) and any other processor-based system or machine. The terms “program code” and “code” refer to any set of instructions that are executed or otherwise processed by a processor. Program code and/or data can be implemented in the form of routines, programs, objects, modules, data structures and the like that perform particular functions. 
     It is noted that the foregoing examples have been provided for the purpose of explanation and are in no way to be construed as limiting. While the invention has been described with reference to various embodiments, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Although the embodiments have primarily been described with reference to multiple virtual machines, the embodiments are not intended to be limited to multiple virtual machines and in fact one virtual machine may be used without departing from the spirit and scope of the present invention. Further, although the embodiments have been described herein with reference to particular means, materials, and examples, the embodiments are not intended to be limited to the particulars disclosed herein; rather, the embodiments extend to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.