Patent Publication Number: US-9430259-B2

Title: Virtualization congestion control framework for modifying execution of applications on virtual machine based on mass congestion indicator in host computing system

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims priority to U.S. Patent Application Ser. No. 61/788,256 (the “&#39;256 application”), filed Mar. 15, 2013 by Michael K. Bugenhagen, entitled, “Virtualization Congestion Control Framework,” the entire disclosure of which is incorporated herein by reference in its entirety for all purposes. 
    
    
     COPYRIGHT STATEMENT 
     A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. 
     FIELD 
     The present disclosure relates, in general, to methods, systems, and computer software for implementing a virtualization congestion control framework. 
     BACKGROUND 
     In a virtual machine (“VM”) environment or cloud virtualized environment, such as in a telecommunications service provider system, congestion issues might arise where one or more applications might request more and more hardware resources, without end and without any means for monitoring the actual hardware (or hardware resource) constraints on the host system. Without any checks on the resource allocation associated with the host system, the one or more applications might request more and more hardware resources until the host system finally and catastrophically crashes. 
     Currently, existing application level congestion control state machines and push back interrupts are hardware specific to vendor platforms. In other words, even though existing application congestion controllers and congestion control state machines might utilize the orchestrator and/or hypervisors to add resources, such elements do not have the functionality for receiving limitations from the cloud to perform push backs to bound and/or reduce the use of hardware resources, and thus cannot ensure that if the application is attacked or running over capacity the application will not crash the system. 
     In addition, even though different hardware from a single vendor might provide for load push back mechanisms and/or dedicated scan rates at the north, south, east, and west bound interfaces of an application congestion controller, by using a protocol with an intelligent device for “buffer monitoring,” such congestion control systems are vendor-specific and do not allow for cross-application congestion control that is required in a global VM environment. Moreover, interfaces in existing VMs are not designed to provide congestion control state inputs. Further, existing congestion control systems are typically one-way controls, without sufficient feedback. 
     As a result, the system can be vulnerable to system hacks, mass call events, or both, where the applications exhaust and consume resources without any limitation or any push back or throttle down application message especially in a mixed application environment from the orchestrator that manages the overall resources of the VM environment. Without such throttling, and load shedding mechanisms the overall inability can render the system too busy to process normal traffic, and can result in the crushing of services and may cause the entire system network to crash. 
     Further, given that applications are mostly stateless and VM sessions can tolerate some small delay, congestion is only monitored at the CPU, memory, and storage levels (not interface), and additional resources are added when an application nears exhausting its allocated resources. The problem with this approach is that turning all communications into the same area with millions of users creates a “mass call event” (e.g., a “September 11” scenario) where use demand can exceed the resources across a cloud environment and exhaust all resources to the level of unacceptable non-performance. Normally, the physical limitations of dedicated hardware act as the threshold for the system triggering a load shedding survival mode. Once utilization approaches the limits of the equipment, non-critical processes are shed via the application congestion engines. Once an application is placed inside of a VM environment those limits are unknown, and can actually be dynamic available or unavailable. Therefore, to retain the application survivability, those utilization limits need to be communicated from the VM orchestrator to the application when congestion and resource limits have been reached. 
     Hence, there is a need for more robust and scalable virtualization congestion solutions. 
     BRIEF SUMMARY 
     Various embodiments provide techniques for implementing a virtualization congestion control framework. In particular, in an environment in which one or more virtual machines (“VMs”) execute on a common hardware platform, a congestion control framework can coordinate resource utilization when being consumed by a plurality of applications (some of which might run within the same VM or different VMs on the same hardware platform). While conventional VM hypervisors provide some resource allocation features, congestion control framework provided by various embodiments can enable substantial additional functionality and control. In an aspect, therefore, the congestion control framework can provide better visibility to a running application about the system&#39;s impact on the underlying hardware platform, as well as the impact of other running applications (either in the same VM or in another VM on the same hardware). Further, the framework can allow the application to communicate its own needs to the hypervisor via an orchestrator. 
     In various embodiments, an orchestrator might be provided within a virtual machine environment context in order to provide two-way communications between the virtual machine (“VM”) and one or more applications running in the VM environment in order to communicate host control congestion states of hardware resource usage. In some cases, the two-way communications might be established using a congestion application programming interface (“API”). In some embodiments, the two-way communications might include communications from the VM to the one or more applications including maximum hardware resources and current hardware resources, and might further include communications from the one or more applications and/or operating systems to the VM including pre-congestion notifications and low-utilization notifications. According to some embodiments, a VM resource buffer utilization feedback may be provided between the VM and the one or more applications. The buffer utilization feedback might allow the orchestrator and/or applications to control pushback mechanisms, while the pushback mechanisms might include mechanisms for pushing back on or decreasing service levels or rates, and pushing back on or decreasing hardware resource usage. 
     In some embodiments, the virtualized application congestion control framework might be a distributed congestion control framework that separates components of the application congestion state machine into the virtual machine layers and distributes the different portions of state machines to specialized VM environment systems so that the application congestion control will function in a VM environment with a VM level congestion control engine. 
     According to some embodiments, various application interfaces, congestion tracking mechanisms, and pushback mechanisms must be distributed in a particular framework (such as described in detail below) to enable the VM environment and the one or more applications to work together to perform congestion management. 
     To ensure the reliability of the communication system, the system needs to pre-assess what amount of resources it can ultimately assign or ration to which applications during an emergency event. In addition, some “operational” overhead or spare buffer resource needs to be allocated to ensure that if a change is required to take place, the resources required to make those adjustments are available. 
     The tools provided by various embodiments include, without limitation, methods, systems, and/or software products. Merely by way of example, a method might comprise one or more procedures, any or all of which are executed by a computer system. Correspondingly, an embodiment might provide a computer system configured with instructions to perform one or more procedures in accordance with methods provided by various other embodiments. Similarly, a computer program might comprise a set of instructions that are executable by a computer system (and/or a processor therein) to perform such operations. In many cases, such software programs are encoded on physical, tangible, and/or non-transitory computer readable media (such as, to name but a few examples, optical media, magnetic media, and/or the like). 
     In one aspect, a system might be provided for implementing a virtualization congestion control framework. The system might comprise a host system connected to a service provider network. The host system might comprise one or more processors, one or more hardware components, and a non-transitory computer readable medium having encoded thereon a set of instructions executable by the one or more processors to perform one or more operations. 
     In some cases, the set of instructions might comprise instructions for establishing a virtual machine environment, instructions for running an application congestion controller within the virtual machine environment, and instructions for establishing one or more interfaces mapping the virtual machine environment with the one or more hardware components of the host system. 
     In some embodiments, the set of instructions might further comprise instructions for establishing a resource usage state module running within the virtual machine environment, and instructions for monitoring, with the resource usage state module, hardware resource usage of the one or more hardware components. 
     The set of instructions, according to some examples, might also comprise instructions for establishing an orchestrator operatively coupled to the application congestion controller and to the resource usage state module, instructions for controlling, with the orchestrator, congestion of hardware resources used by one or more applications running on one or more virtual machines in the virtual machine environment, instructions for establishing, with the orchestrator, two-way communications between the virtual machine environment and the one or more applications running on the one or more virtual machines, and instructions for modifying, with the orchestrator, an allocation of hardware resources to the one or more applications. 
     In another aspect, a system might be provided for implementing a virtualization congestion control framework. The system might comprise a host system connected to a service provider network. The host system might comprise one or more processors, one or more hardware components, and a non-transitory computer readable medium having encoded thereon a set of instructions executable by the one or more processors to perform one or more operations. 
     In some embodiments, the set of instructions might comprise instructions for establishing, with an orchestrator, two-way communications between a virtual machine environment established within the host computer system and one or more applications running on one or more virtual machines in the virtual machine environment. The set of instructions might further comprise instructions for modifying, with the orchestrator, an allocation of hardware resources of the one or more hardware components to the one or more applications, based on the two-way communication between the virtual machine environment and the one or more applications. 
     In some cases, the set of instructions might include instructions for recovering, with the orchestrator, hardware resources from a first application, in response to receiving a notification indicating low utilization of hardware resources by the first application. 
     According to some embodiments, the set of instructions might include instructions for monitoring, with the orchestrator, the hardware resource usage for mass congestion indicators. In some cases, the set of instructions might further include instructions for determining, with the orchestrator, whether mass congestion indicators are present, and for, in response to a determination that mass congestion indicators are present, modifying, with the orchestrator, hardware resource allocations downward to reflect congestion control. In some embodiments, modifying, with the orchestrator, hardware resource allocations downward to reflect congestion control might include sending, with the orchestrator, signals to at least one of the one or more applications to begin load shedding. In some instances, modifying, with the orchestrator, hardware resource allocations downward to reflect congestion control might include adjusting, with the orchestrator, to pre-set congestion boundaries by causing a forced load shedding of at least one of the one or more applications. 
     In yet another aspect, a method might be provided for implementing a virtualization congestion control framework. The method might comprise establishing, with an orchestrator on a host computer system, two-way communications between a virtual machine environment established within the host computer system and one or more applications running on one or more virtual machines in the virtual machine environment. The method might further comprise modifying, with the orchestrator, an allocation of hardware resources of the one or more hardware components to the one or more applications, based on the two-way communication between the virtual machine environment and the one or more applications. 
     In still another aspect, a computer software might be provided that might be encoded on a non-transitory computer readable medium of a host system. The computer software might comprise a set of instructions executable by one or more processors of the host system to perform one or more operations. The set of instructions might comprise instructions for establishing, with an orchestrator on the host computer system, two-way communications between a virtual machine established within the host computer system and one or more applications running on one or more virtual machines in the virtual machine environment. The set of instructions might further comprise instructions for modifying, with the orchestrator, an allocation of hardware resources of the one or more hardware components to the one or more applications, based on the two-way communication between the virtual machine environment and the one or more applications. 
     Various modifications and additions can be made to the embodiments discussed without departing from the scope of the invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combination of features and embodiments that do not include all of the above described features. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A further understanding of the nature and advantages of particular embodiments may be realized by reference to the remaining portions of the specification and the drawings, in which like reference numerals are used to refer to similar components. In some instances, a sub-label is associated with a reference numeral to denote one of multiple similar components. When reference is made to a reference numeral without specification to an existing sub-label, it is intended to refer to all such multiple similar components. 
         FIG. 1  is a block diagram illustrating a system for controlling virtualization congestion, in accordance with various embodiments. 
         FIG. 2  is a block diagram illustrating an exemplary system for controlling virtualization congestion, in accordance with various embodiments. 
         FIG. 3  is a flow diagram illustrating a method for implementing virtualization congestion control and hardware resource allocation and management, in accordance with various embodiments. 
         FIG. 4  is a block diagram illustrating an exemplary computer or system hardware architecture, in accordance with various embodiments. 
     
    
    
     DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS 
     While various aspects and features of certain embodiments have been summarized above, the following detailed description illustrates a few exemplary embodiments in further detail to enable one of skill in the art to practice such embodiments. The described examples are provided for illustrative purposes and are not intended to limit the scope of the invention. 
     In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the described embodiments. It will be apparent to one skilled in the art, however, that other embodiments of the present invention may be practiced without some of these specific details. In other instances, certain structures and devices are shown in block diagram form. Several embodiments are described herein, and while various features are ascribed to different embodiments, it should be appreciated that the features described with respect to one embodiment may be incorporated with other embodiments as well. By the same token, however, no single feature or features of any described embodiment should be considered essential to every embodiment of the invention, as other embodiments of the invention may omit such features. 
     Unless otherwise indicated, all numbers used herein to express quantities, dimensions, and so forth used should be understood as being modified in all instances by the term “about.” In this application, the use of the singular includes the plural unless specifically stated otherwise, and use of the terms “and” and “or” means “and/or” unless otherwise indicated. Moreover, the use of the term “including,” as well as other forms, such as “includes” and “included,” should be considered non-exclusive. Also, terms such as “element” or “component” encompass both elements and components comprising one unit and elements and components that comprise more than one unit, unless specifically stated otherwise. 
     Various embodiments provide techniques for implementing a virtualization congestion control framework. In particular, in an environment in which one or more VMs execute on a common hardware platform, a congestion control framework can coordinate resource utilization by a plurality of applications (some of which might run within the same VM or different VMs on the same hardware platform). While conventional VM hypervisors provide some resource allocation features, congestion control framework provided by various embodiments can enable substantial additional functionality and control. Merely by way of example, in particular aspects, the framework can provide a congestion controller that can allocate resources to, and/or withdraw resources from, an application dynamically. In some cases, the congestion controller can allocate resources to (and/or withdraw resources from) an application in a different manner when the system is under stress, than when in normal operating conditions. In another aspect, the controller (and/or an orchestrator component) might provide two-way communication between the application and the underlying hardware platform, converse to the abstraction typically provided by a hypervisor. This two-way communication can better enable an application to request additional resources (and/or determine whether such resources are available for request) and/or notify the system that resources can be withdrawn. 
     In an aspect, therefore, the congestion control framework can provide better system state visibility on a running application&#39;s impact on the underlying hardware platform, as well as the impact of other running applications (either in the same VM or in another VM on the same hardware). Further, the framework can allow the application and operating systems to communicate its own needs to the hypervisor. These features can allow, for example, the orchestrator to forcefully withdraw resources from an application. In some cases, pushback or throttle down functionality is provided for forcefully withdrawing resources. In some instances, the orchestrator forcefully withdrawing resources from an application might include the orchestrator requesting that the application load shed and dynamically reduce its workload and/or resource utilization (which might be measured in clients serviced, transactions per second, input/output (“I/O”) operations, network utilization, processor utilization, and/or any other metric) to prevent system overload, avoid performance degradation (and/or catastrophic failure) of that application or other applications, and the like. By the same token, however, the framework, in some embodiments, can also allow an application to inform the orchestrator that it needs more resources (or will need more resources in the future) to accommodate increasing load. Thus, various embodiments enable enhanced negotiation between an application and an orchestrator (and/or the underlying hardware) with respect to resource utilization. In an aspect of other embodiments, this framework can also provide an application with the ability to control the load imposed on that application by external entities (which might be peer servers, upstream load controllers, and/or downstream clients). 
     Herein, the term “congestion” might refer to one or more applications utilizing sufficient hardware resources of the hardware interface that at least one of the one or more applications becomes negatively impacted. The term “running over capacity” might refer to one or more applications using more than the available hardware resources, such as to contribute to congestion. The term “crash” might refer to a catastrophic failure of the network or system, which might result from one or more applications “running over capacity” and/or being attacked. “Pushback” might refer to a reduction in the use of hardware resources, typically as a result of notification of congestion, running at or over capacity, or eminent crash. 
     A “hypervisor” might be a virtual machine manager (“VMM”), which might be a component of computer software, firmware, and/or hardware that creates and runs virtual machines. The “hypervisor” might run one or more VMs on a computer defined as a “host machine,” and each of the one or more VMs might be defined as a “guest machine.” In operation, the “hypervisor” might provide the “guest machines” or operating systems of the “guest machines” with a virtual operating platform, and might manage the execution of the “guest machine” operating systems. 
     The term “business support system” (“BSS”) might refer to components that a service provider (such as a telephone operator or telecommunications company) might use to run its business operations, including, for example, taking orders, handling payment issues, or dealing with revenues, and the like. BSS might generally cover the four main areas of product management, customer management, revenue management, and order management. In a related manner, the term “operations support system” (“OSS”) might refer to components used by telecommunications service providers to deal with the telecommunications network itself, supporting processes including, but not limited to, maintaining network inventory, provisioning services, configuring network components, managing faults, and the like. The two systems functioning together might be referred to as “BSS/OSS.” 
     An “advanced intelligent network” (“AIN”) might refer to any telephone network that queries a database before a telephone call is sent to its final destination in order to determine how to handle or route the call. A typical AIN might provide the following two main functionalities: (1) the AIN might be able to affect or change the routing of calls within it from moment to moment, based on some criteria; and (2) the AIN might allow the originator or the ultimate receiver of the call to somehow inject intelligence into the network to affect the flow of the outbound or inbound call. Typically, AINs might comprise signal control points (“SCPs”), signal switching points (“SSPs”), and signal transfer points (“STPs”), all of which might communicate via out-of-band signaling, using, for example, signaling system 7 (“SS7”) protocol. SCPs are typically computers that hold databases in which customer-specific information used by the network for routing calls might be stored. SSPs are typically digital telephone switches that communicate with SCPs to request for customer-specific instructions pertaining to call completion. STPs are typically packet switches that shuttle messages between SSPs and SCPs. 
     An “application programming interface” (“API”) might refer to a protocol intended to be used as an interface by software components to communicate with each other. 
     “Virtualization” might refer to a process of mapping hardware resources to create “virtual machine resource” within the framework of the VMs so that the VM environment may utilize the hardware resources. For example, each of the north, south, east, and west interfaces shown in  FIGS. 1 and 2  are parts of physical and/or virtual links that have been apportioned or “virtualized” to an application as a port to the application, which might be associated with various external components (i.e., BSS/OSS, AIN, second autonomous systems, customers, and the like) via the hardware or host system on which the VM is running. 
     With reference to the figures,  FIG. 1  is a block diagram illustrating a system  100  for controlling virtualization congestion, in accordance with various embodiments. In system  100  as shown in  FIG. 1 , computer or hardware system  105  might serve as a host machine or host system that creates and operates a virtual environment (or virtual machine environment)  110 , in which an application congestion controller  115  (also referred to herein as an “application controller” or a “congestion engine”) might run. The application congestion controller  115  might be operatively coupled to a number of interfaces or components, including, but not limited to, a north or north bound interface  120 , east/west interfaces  125 , south or south bound interface  130 , a hypervisor  135 , a resource usage state module  140 , and an orchestrator  165 , all of which might be executed within the virtual environment  110 . 
     System  100  might further comprise a BSS/OSS  145 , an AIN  150 , one or more second autonomous systems  155 , and one or more customers  160 . In some embodiments, second autonomous systems  155  might include a computer or hardware system that might be similar to, identical to, or different from computer or hardware system  105 . The one or more customers  160  might include customers  160   a ,  160   b , through  160   n . Each of customers  160   a ,  160   b , through  160   n  might comprise a customer device including, but not limited to, POTS telephones, voice over Internet protocol (“VoIP”) telephones, cellular telephones, smart phones, tablet computers, laptop computers, desktop computers, or the like. 
     Computer or hardware system  105  and the second autonomous systems  155  might be located in another service provider network, or might be physically different systems not inside the VM environment but still in the service provider facilities or premises, and might be associated with one or more of VoIP switches, Internet protocol television (“IPTV”) servers, content delivery networks (“CDNs”), Internet servers, other network servers, and the like. In some cases, the computer or hardware system  105  and/or the second autonomous systems  155  might comprise one or more of VoIP servers or switches, IPTV servers, content servers (in a CDN), Internet servers, SS7 nodes, and/or other AIN elements, other network servers, and the like. In a particular aspect, such servers can be implemented as applications within a VM or multiple separate VMs on the hardware system  105  and/or the second autonomous systems  155 . 
     As an example, a first customer (e.g., customer  160   a ) might communicate with a second customer (e.g., customer  160   b ) via telephone through AIN  150  via a first application (e.g., a VoIP server or switch) running on a first VM within the virtual environment  110  running on the computer or hardware system  105 , via the south bound interface  130  and the east/west interface  125 . Meanwhile, a third customer (e.g., customer  160   n ) might be streaming a high-definition (“HD”) movie via an IPTV server associated with one of the one or more second autonomous systems  155  via a second application running on a second VM within the virtual environment  110 , via the south bound interface  130  and the east/west interface  125 . At the same time, the BSS/OSS  145  might be providing business and/or operational support to one or more customers and customer connections via a third application running on a third VM within the virtual environment  110 , via the north bound interface  120  and the south bound interface  130 . In some aspects, the first, second, and third VMs might be the same VM, or any two of the first, second, or third VMs might be the same VM. In other aspects, the first, second, and third VMs are separate VMs. 
     While all of these processes are running, the resource usage state module  140  might monitor the physical and virtual states—that is, the physical state of the underlying computer or hardware system  105 , and the virtual states of the virtual machine environment  110  or of each of the VMs running within the virtual machine environment  110 , which can be managed by a hypervisor  135 . In some cases, virtualized resources might be mapped to physical hardware resources of the hardware system  105 . The virtualized resources might include any one or more of virtualized CPU resource, virtualized memory resource, virtualized disc storage resource, or virtualized interface resource. 
     An application controller/congestion engine  115  might receive requests for more hardware resources (e.g., CPU memory storage resources, and the like) of the computer or hardware system  105  (i.e., host system) from one or more of the first, second, or third applications. In some cases, the application congestion engine  115  might incorporate and/or might be incorporated within the functionality of the orchestrator  165  and hypervisor  135 , while in other cases, the application controller might be a software component separate from the hypervisor  135 . 
     An orchestrator without system constraints might typically continue to add more and more resources in response to the requests from each of the one or more of the first, second, or third applications running on the respective first, second, or third VMs, such that congestion occurs, which might lead to one or more applications “running over capacity,” in turn resulting in a crash of the host system (i.e., computer or hardware system  105 ). Such a crash might interrupt services for some or all of the customers  160 , and perhaps also customers associated with the one or more second autonomous systems  155 . 
     One solution to this problem might include the use of a protocol with an intelligent device to implement push back message from the orchestrator to applications to start shedding load and reduce use of resources running on one or more VMs in the virtual environment  110 . In some cases, overload conditions might be detected via communication interfaces, each of the interfaces  120 - 130  might contain “buffer monitoring” which can detect mass call conditions that cause the protocol stacks to be overflowing. Normally, an application would start pushing back on demands by sending “busy” congestion messages to slow the number of call setups per second, or it simply could start ignoring incoming messages, which is analogous to changing how often the system offers service historically referred to as scan rates in the interfaces  120 - 130  which are changed during congestion to shed processing requirements. 
     Commonly, once application load shedding occurs non-essential processes are shut down, and if required the number of sessions processed per second is reduced in order for the system to survive the mass call event. 
     We now turn to  FIG. 2 , which is a block diagram illustrating an exemplary system  200  for controlling virtualization congestion, in accordance with various embodiments. In  FIG. 2 , system  200  might comprise computer or hardware system  205 . Computer or hardware system  205 , in some embodiments, might serve as a host machine or host system that creates and operates a virtual environment (or virtual machine environment)  210 , in which an application congestion controller  215  might run. The application congestion controller  215  (also referred to herein as an “application controller” or a “congestion engine”) might be operatively coupled to a number of interfaces or components, including, but not limited to, a north or north bound interface  220 , east/west interfaces  225 , south or south bound interface  230 , a hypervisor  235 , and a resource usage state module  240 , all of which might be executed within the virtual environment  210 . 
     System  200  might further comprise a BSS/OSS  245 , an AIN  250 , one or more second autonomous systems  255 , and one or more customers  260 . In some embodiments, second autonomous systems  255  might include a computer or hardware system that might be similar to, identical to, or different from computer or hardware system  205 . The one or more customers  260  might include customers  260   a ,  260   b , through  260   n . Each of customers  260   a ,  260   b , through  260   n  might comprise a customer device including, but not limited to, POTS telephones, voice over Internet protocol (“VoIP”) telephones, cellular telephones, smart phones, tablet computers, laptop computers, desktop computers, or the like. 
     Computer or hardware system  205  and the second autonomous systems  255  might be located at service provider facilities or premises, and might be associated with one or more of VoIP switches, IPTV servers, content servers (e.g., in a CDN), Internet servers, other network servers, and the like. In some cases, the computer or hardware system  205  and/or the second autonomous systems  255  might comprise one or more of VoIP switches/servers, IPTV servers, content servers, Internet servers, other network servers, and the like (each of which could be running as an application on a VM within the virtual environment  210 ). In a particular aspect, such servers can be implemented as applications within a VM or multiple separate VMs on the hardware system  205  and/or the second autonomous systems  255 . 
     According to some embodiments, computer or hardware system  205 , virtual environment (or virtual machine environment)  210 , application congestion controller  215 , north bound interface  220 , east/west interfaces  225 , south bound interface  230 , hypervisor  235 , resource usage state module  240 , BSS/OSS  245 , AIN  250 , the one or more second autonomous systems  255 , and the one or more customers  260  might be the same or similar in terms of structure, functionality, or the like as the corresponding components in  FIG. 1 . 
     Turning back to  FIG. 2 , system  200  might further comprise orchestrator  265 , which might include an orchestrator  265   a  external to the computer or hardware system  205 , an orchestrator  265   b  running on the virtual environment  210  on the computer or hardware system  205 , or both. Each orchestrator might comprise a mass event state engine  270  (i.e., orchestrator  265   a  might comprise mass event state engine  270   a , while orchestrator  265   b  might comprise mass event state engine  270   b , as shown in  FIG. 2 ). Each mass event state engine  270  might be configured to monitor for mass events and/or mass congestion indicators. 
     Unlike a conventional hypervisor, the orchestrator  265  might coordinate with the resource usage state module  240  (i.e., by communicating with it) to identify the maximum hardware resources of the host system  205 , as well as the currently used hardware resources and the currently available resources. Based on such identifications or determinations, the orchestrator  265  might regulate, rather than simply allocate, hardware resources (e.g., CPU memory storage resources, and the like) that might be used by the applications running on the one or more VMs in the virtual environment  210 . In other words, the orchestrator  265  might establish bounds for resources allocated to each application based on these determinations, and perhaps based on priority or importance of each application. For example, government and/or emergency service applications (including, but not limited to, Government Emergency Telecommunications Service (“GETS”), or the like) might be given top priority and provided with all the available hardware resources in lieu of other lower priority applications. In some cases, the orchestrator  265  might push back on the excessive hardware resource usage by the one or more applications. According to some embodiments, the orchestrator  265  might provide the one or more applications with a mechanism for controlling push back (see, for example, the buffer utilization feedback discussed below). 
     Further, the orchestrator  265  might concurrently monitor for mass events and/or mass congestion, by monitoring for indicators of mass events and/or mass congestion using mass event state engine  270 . In some cases, such indicators might include, without limitation, a predetermined threshold level of resource usage being exceeded, or a determination that an emergency reserve that is set aside out of the available resources begins to be used, or the like. In some embodiments, such indicators might include receiving requests for service or resource usage that exceeds normal or typical usage requests. For example, a normal call volume in New York might typically be about 100 calls per second, but during events of “September 11,” about 4000 calls per second were being connected (or terminated). In other words, the indicators of mass events might include exceeding the normal number of call requests by a predetermined threshold (including, but not limited to 300%, 400%, 500%, 1000% of normal/typical levels, or the like). 
     Based on a determination that such indicators are present, the orchestrator  265  might modify resource allocations downward to reflect congestion control (to adjust to pre-set congestion boundaries, or the like), and might send signals to one or more applications to load shed (i.e., to reduce the amount of resource usage). The application congestion controller  215  might comprise a load shedding function  275 , which might cause the one or more applications to begin load shedding. In some cases, the load shedding function  275  might cause load shedding (or forced load shedding) of one application at a time. In other cases, the load shedding function  275  might cause load shedding (or forced load shedding) of more than one application at a time. 
     Orchestrator  265  might provide two-way communication with each of the applications (e.g., the first, second, and third applications described above with respect to  FIG. 1 ) running on the one or more VMs (e.g., the first, second, and third VMs described above) in the virtual environment  210  on the computer or hardware system  205 . The two-way communications might include information regarding maximum hardware resources and information regarding current (used or available) hardware resources provided from the orchestrator  265  (or from the one or more VMs or from the hypervisor  235 ) running in the virtual environment  210  on the computer or hardware system  205  to each of the applications. In a mass event, where the Orchestrator controller has set a limit for an application, the application controller needs to know that it needs to load shed inside of the currently allocated resources. To facilitate this, the two-way communications might also include a system pre-congestion notification from the orchestrator  265  to each of the applications, prior to reaching the limit on the available resources (which might occur, e.g., when an emergency reserve that is set aside out of the available resources begins to be used, or the like). The system pre-congestion notification might include three types of messages: (1) “start load shedding”; (2) “load shed on your own”; and (3) “stop cross-utilization during mass event and/or mass congestion.” The two-way communications might further include an application pre-congestion notification or a low utilization notification from one or more applications to the orchestrator  265  (or to the one or more VMs or to the hypervisor  235 ). The application pre-congestion notification might include a notification to the orchestrator  265  indicating that the one or more applications might be (or might soon be) utilizing more resources that might result in congestion. A protocol—including, but not limited to, a congestion application programming interface (“API”)—might be utilized to establish (and/or maintain) the two-way communications between the one or more VMs (or the hypervisor  235 ) and each of the applications. 
     Because the orchestrator  265  provides two-way communications between the one or more VMs (or the hypervisor  235 ) and the applications, there is continual negotiation and collaboration amongst the various components, such that sudden failure, sudden service drops, sudden interruptions, and the like are mitigated or obviated. Accordingly, the orchestrator  265 , in response to a notification from one or more applications requesting more hardware resources, might be able to determine whether there are any available resources (by obtaining the information regarding maximum hardware resources and information regarding current (used or available) hardware resources from the resource usage status module  240 ). Based on a determination that there are available resources, the orchestrator  265  might allocate the requested hardware resources to the one or more requesting applications. On the other hand, if it is determined that insufficient hardware resources are available, the orchestrator  265  might determine which of the one or more requesting applications are priority applications, or might rank the one or more requesting applications according to priority (e.g., GETS applications or other emergency telephone applications might have priority over a normal VoIP application, etc.). 
     Likewise, in response to a notification from one or more applications indicating low utilization of hardware resources, the VM  210 , the hypervisor  235 , or the orchestrator  265  might recover some or all of the unused or under-utilized hardware resources from the one or more low-usage applications. 
     In some embodiments, during a non-congestion condition (e.g., a normal condition), the one or more applications might request hardware resources and might receive all the requested hardware resources. However, in a congestion condition (such as described above), which might be triggered by a determination that mass event and/or mass congestion indicators are present, the orchestrator might cause the one or more applications to drop resource usage to preset congestion boundaries. In some cases, the preset congestion boundaries might include setting aside a first portion of the hardware resources as an emergency reserve (e.g., for GETS or other emergency or government application, or the like), a second portion that is equally divided amongst the one or more applications. For example, for two applications running in the VM environment, the preset congestion boundaries might include 20% of the resources set aside for the emergency reserve, 40% for the first application, and 40% for the second application. In such an example, the orchestrator might cause forced load shedding of the first and second applications to the 40% level for each application, in the case that these applications do not load shed on their own to that level. In other cases, rather than equally dividing the second portion amongst the one or more applications, the second portion might be proportionally divided amongst the one or more applications based on current resource usage at, or prior to, the time the congestion condition is triggered. For example, if, during normal conditions, the first application used three times as many resources as the second application, then the preset congestion boundaries might include 20% for the emergency reserve, 60% for the first application, and 20% for the second application. Although the examples above refer to two applications, any number of applications might be running at the same time, and the equal or proportional portions of the second portion might be allocated accordingly. 
     According to some embodiments, to facilitate state tracking at the virtualized north interface  220 , the east/west interface  225 , and the south interface  230 , buffer utilization feedback via the hypervisor  235  and possibly through the orchestrator  265  might be added to the applications from the VM environment  210 . In such a case, the applications might be provided with the ability or capability to control the pushback mechanism through this input (i.e., the buffer utilization feedback input) by detecting high utilization rates, and triggering congestion control via signaling autonomous systems to slow down their call processing to the application. 
       FIG. 3  is a flow diagram illustrating a method  300  for implementing virtualization congestion control and hardware resource allocation and management, in accordance with various embodiments. In  FIG. 3 , process  300  might comprise assigning, with an orchestrator (e.g., orchestrator  265 ), application VM resources with maximum allowable settings to one or more applications (block  305 ). At block  310 , the one or more applications might start (i.e., might begin execution in the VM environment). 
     The resource use by at least one of the one or more applications might change (block  315 ). Alternatively, or in addition, one or more of the applications might start load shedding (i.e., decreasing resource usage). In both cases, resource usage might change; in some cases, this might include overall resource usage or resource usage of some of the resources. At block  320 , a hypervisor (e.g., hypervisor  235 ) might monitor the actual hardware resource utilization (e.g., by using resource usage state module  240 , or the like), and might update the orchestrator with the actual hardware resource usage. In other cases, the orchestrator might directly communicate with the resource usage state module  240 , or the like. The orchestrator might, at block  325 , monitor for high utilization, based on the hardware resource usage information from the hypervisor. A determination might then be made, at block  330 , by the orchestrator as to whether there is high utilization of hardware resources by at least one application. If it is determined that there is no high utilization of hardware resources by any or all applications, the process  300  might return to block  315 , and might wait for a change in either resource use by at least one of the one or more applications and/or resource usage. If it is determined, however, that there is high utilization by at least one application, the process  300  might proceed to block  335 . 
     At block  335 , the orchestrator might cause resource allocation of the at least one application to change (either upwards or downwards). Alternatively, or in addition, the orchestrator might cause resource allocation of applications other than the at least one application to change (either upwards or downwards). In some cases, the orchestrator might force one or more applications to decrease its resource usage (“forced load shedding”). In other cases, such as when a first application sends a low utilization notification to the orchestrator, while a second application sends an application pre-congestion notification, the orchestrator might cause the resource allocation of the first application to decrease (i.e., recover hardware resources from the first application), and might thereafter cause the resource allocation of the second application to increase. The process might return to block  315 , where the resource use by the one or more applications (and accordingly the resource usage) might change in response to the resource allocation changes (e.g., recovery, forced load shedding, or greater allocation, or the like) caused by the orchestrator. 
     Concurrent with the steps at blocks  310 - 335 , the orchestrator might, at block  340 , actively or continually monitor for mass congestion and/or mass event indicators (which might include, without limitation, a predetermined trigger or utilization or performance threshold level of resource usage being exceeded, or a determination that an emergency reserve that is set aside out of the available resources begins to be used, or the like). A predetermined threshold value might include, without limitation, a percentage of maximum CPU resources, a percentage of maximum memory resources, a percentage of maximum disc storage resource, a percentage of maximum interface resources, a combination of these percentages, an overall percentage of maximum resources, a fixed amount corresponding to available resources among any one or more of CPU resources, memory resources, disc storage resources, or interface resources. 
     For example, if the maximum memory is 200 gigabytes or 200 GBs, while the total current memory usage is 191 GBs, and the threshold level is 90%, then the total current memory usage (191 GBs) exceeds 90% of the maximum memory. Although this example uses a threshold level of 90%, any appropriate level (including, without limitation, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or any range of threshold percentages, e.g., between 80% and 100%, or the like, may be used). Although percentages are used in the example, fixed amounts may be used. For instance, a threshold value of 150 GBs, 175 GBs, 190 GBs, 195 GBs, or the like (for a maximum memory size of 200 GBs, for example), or any equivalent proportion of any other maximum memory size, may be used as the threshold level. In other examples, the threshold value might include, without limitation, 300%, 400%, 500%, 1000% of normal/typical levels, or the like. Any other suitable threshold values may also be used, as appropriate. 
     A determination might be made, by the orchestrator at block  345 , as to whether a mass congestion indicator is present. Based on a determination that a mass congestion indicator is not present, the process  300  returns to block  340 , at which the orchestrator continues to monitor. On the other hand, if a determination is made that a mass congestion indicator is present, the process  300  might proceed to block  350 . 
     In such a case, the orchestrator might determine that resource allocations should be modified, and as a result, at block  350 , the orchestrator might modify allocations of resource usage downward to reflect congestion control. The orchestrator might, at block  355 , send signals to the one or more applications to load shed or to begin load shedding (in a manner akin to a passive request, compared with the forced load shedding), which might result in at least one of the one or more applications starting to load shed (at block  315 ). The orchestrator might concurrently, or sequentially, start adjusting to pre-set congestion boundaries (block  360 ), which might result in the orchestrator implementing forced load shedding (block  335 ) in the case that the at least one of the one or more applications does not start to load shed based on the signals sent at block  355 . Thereafter, the process might return to block  340 , at which the orchestrator might continue to actively monitor for mass congestion and/or mass event indicators. 
     In any event, priority applications (including, but not limited to, GETS or some other emergency or government application, or the like) might be exempt from any load shedding or any forced load shedding. In other words, the orchestrator might send signals to other applications to load shed and/or might cause forced load shedding of other applications, but (by design) will not in any way slow down priority applications such as GETS or other emergency or government applications. As discussed above with respect to  FIG. 2 , during a normal condition, the one or more applications might receive all the resources that each application requests. However, during a congestion condition, the orchestrator might adjust usages to pre-set congestion boundaries, which might include, without limitation, a first portion for an emergency reserve (e.g., for the priority applications including GETS, other emergency applications, and the like), and a second portion for the applications. The second portion, in some cases, might be divided equally amongst all of the one or more applications, while, in other cases, might be divided proportionally amongst the one or more applications based on proportion of hardware resource usage prior to, or at the time of, the congestion trigger (i.e., at the time a determination is made that mass congestion and/or mass event indicators are present). 
       FIG. 4  is a block diagram illustrating an exemplary computer or system hardware architecture, in accordance with various embodiments.  FIG. 4  provides a schematic illustration of one embodiment of a computer system  400  of the service provider system hardware that can perform the methods provided by various other embodiments, as described herein, and/or can perform the functions of computer or hardware system (i.e., host system)  105 ,  205  as described above. It should be noted that  FIG. 4  is meant only to provide a generalized illustration of various components, of which one or more (or none) of each may be utilized as appropriate.  FIG. 4 , therefore, broadly illustrates how individual system elements may be implemented in a relatively separated or relatively more integrated manner. 
     The computer or hardware system  400 —which might represent an embodiment of the computer or hardware system or host system  105 ,  205  described above with respect to  FIGS. 1 and 2 —is shown comprising hardware elements that can be electrically coupled via a bus  405  (or may otherwise be in communication, as appropriate). The hardware elements may include one or more processors  410 , including without limitation one or more general-purpose processors and/or one or more special-purpose processors (such as digital signal processing chips, graphics acceleration processors, and/or the like); one or more input devices  415 , which can include without limitation a mouse, a keyboard and/or the like; and one or more output devices  420 , which can include without limitation a display device, a printer, and/or the like. 
     The computer or hardware system  400  may further include (and/or be in communication with) one or more storage devices  425 , which can comprise, without limitation, local and/or network accessible storage, and/or can include, without limitation, a disk drive, a drive array, an optical storage device, solid-state storage device such as a random access memory (“RAM”) and/or a read-only memory (“ROM”), which can be programmable, flash-updateable and/or the like. Such storage devices may be configured to implement any appropriate data stores, including without limitation, various file systems, database structures, and/or the like. 
     The computer or hardware system  400  might also include a communications subsystem  430 , which can include without limitation a modem, a network card (wireless or wired), an infra-red communication device, a wireless communication device and/or chipset (such as a Bluetooth™ device, an 802.11 device, a WiFi device, a WiMax device, a WWAN device, cellular communication facilities, etc.), and/or the like. The communications subsystem  430  may permit data to be exchanged with a network (such as the network described below, to name one example), with other computer or hardware systems, and/or with any other devices described herein. In many embodiments, the computer or hardware system  400  will further comprise a working memory  435 , which can include a RAM or ROM device, as described above. 
     The computer or hardware system  400  also may comprise software elements, shown as being currently located within the working memory  435 , including an operating system  440 , device drivers, executable libraries, and/or other code, such as one or more application programs  445 , which may comprise computer programs provided by various embodiments (including, without limitation, hypervisors, VMs, and the like), and/or may be designed to implement methods, and/or configure systems, provided by other embodiments, as described herein. Merely by way of example, one or more procedures described with respect to the method(s) discussed above might be implemented as code and/or instructions executable by a computer (and/or a processor within a computer); in an aspect, then, such code and/or instructions can be used to configure and/or adapt a general purpose computer (or other device) to perform one or more operations in accordance with the described methods. 
     A set of these instructions and/or code might be encoded and/or stored on a non-transitory computer readable storage medium, such as the storage device(s)  425  described above. In some cases, the storage medium might be incorporated within a computer system, such as the system  400 . In other embodiments, the storage medium might be separate from a computer system (i.e., a removable medium, such as a compact disc, etc.), and/or provided in an installation package, such that the storage medium can be used to program, configure and/or adapt a general purpose computer with the instructions/code stored thereon. These instructions might take the form of executable code, which is executable by the computer or hardware system  400  and/or might take the form of source and/or installable code, which, upon compilation and/or installation on the computer or hardware system  400  (e.g., using any of a variety of generally available compilers, installation programs, compression/decompression utilities, etc.) then takes the form of executable code. 
     It will be apparent to those skilled in the art that substantial variations may be made in accordance with specific requirements. For example, customized hardware (such as programmable logic controllers, field-programmable gate arrays, application-specific integrated circuits, and/or the like) might also be used, and/or particular elements might be implemented in hardware, software (including portable software, such as applets, etc.), or both. Further, connection to other computing devices such as network input/output devices may be employed. 
     As mentioned above, in one aspect, some embodiments may employ a computer or hardware system (such as the computer or hardware system  400 ) to perform methods in accordance with various embodiments of the invention. According to a set of embodiments, some or all of the procedures of such methods are performed by the computer or hardware system  400  in response to processor  410  executing one or more sequences of one or more instructions (which might be incorporated into the operating system  440  and/or other code, such as an application program  445 ) contained in the working memory  435 . Such instructions may be read into the working memory  435  from another computer readable medium, such as one or more of the storage device(s)  425 . Merely by way of example, execution of the sequences of instructions contained in the working memory  435  might cause the processor(s)  410  to perform one or more procedures of the methods described herein. 
     The terms “machine readable medium” and “computer readable medium,” as used herein, refer to any medium that participates in providing data that causes a machine to operate in a specific fashion. In an embodiment implemented using the computer or hardware system  400 , various computer readable media might be involved in providing instructions/code to processor(s)  410  for execution and/or might be used to store and/or carry such instructions/code (e.g., as signals). In many implementations, a computer readable medium is a non-transitory, physical, and/or tangible storage medium. Such a medium may take many forms, including, but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media includes, for example, optical and/or magnetic disks, such as the storage device(s)  425 . Volatile media includes, without limitation, dynamic memory, such as the working memory  435 . Transmission media includes, without limitation, coaxial cables, copper wire and fiber optics, including the wires that comprise the bus  405 , as well as the various components of the communication subsystem  430  (and/or the media by which the communications subsystem  430  provides communication with other devices). Hence, transmission media can also take the form of waves (including without limitation radio, acoustic and/or light waves, such as those generated during radio-wave and infra-red data communications). 
     Common forms of physical and/or tangible computer readable media include, for example, a floppy disk, a flexible disk, a hard disk, magnetic tape, or any other magnetic medium, a CD-ROM, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wave as described hereinafter, or any other medium from which a computer can read instructions and/or code. 
     Various forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to the processor(s)  410  for execution. Merely by way of example, the instructions may initially be carried on a magnetic disk and/or optical disc of a remote computer. A remote computer might load the instructions into its dynamic memory and send the instructions as signals over a transmission medium to be received and/or executed by the computer or hardware system  400 . These signals, which might be in the form of electromagnetic signals, acoustic signals, optical signals, and/or the like, are all examples of carrier waves on which instructions can be encoded, in accordance with various embodiments of the invention. 
     The communications subsystem  430  (and/or components thereof) generally will receive the signals, and the bus  405  then might carry the signals (and/or the data, instructions, etc. carried by the signals) to the working memory  435 , from which the processor(s)  405  retrieves and executes the instructions. The instructions received by the working memory  435  may optionally be stored on a storage device  425  either before or after execution by the processor(s)  410 . 
     While certain features and aspects have been described with respect to exemplary embodiments, one skilled in the art will recognize that numerous modifications are possible. For example, the methods and processes described herein may be implemented using hardware components, software components, and/or any combination thereof. Further, while various methods and processes described herein may be described with respect to particular structural and/or functional components for ease of description, methods provided by various embodiments are not limited to any particular structural and/or functional architecture but instead can be implemented on any suitable hardware, firmware and/or software configuration. Similarly, while certain functionality is ascribed to certain system components, unless the context dictates otherwise, this functionality can be distributed among various other system components in accordance with the several embodiments. 
     Moreover, while the procedures of the methods and processes described herein are described in a particular order for ease of description, unless the context dictates otherwise, various procedures may be reordered, added, and/or omitted in accordance with various embodiments. Moreover, the procedures described with respect to one method or process may be incorporated within other described methods or processes; likewise, system components described according to a particular structural architecture and/or with respect to one system may be organized in alternative structural architectures and/or incorporated within other described systems. Hence, while various embodiments are described with—or without—certain features for ease of description and to illustrate exemplary aspects of those embodiments, the various components and/or features described herein with respect to a particular embodiment can be substituted, added and/or subtracted from among other described embodiments, unless the context dictates otherwise. Consequently, although several exemplary embodiments are described above, it will be appreciated that the invention is intended to cover all modifications and equivalents within the scope of the following claims.