Abstract:
Methods, systems, and apparatus, including computer program products, for assuring application performance by matching the supply of resources (e.g., application resources, VM resources, or physical resources) with the fluctuating demand placed on the application. For example, the systems and methods disclosed herein can be used to ensure that the application is allocated sufficient resources when it is initially deployed to handle anticipated demand; dynamically alter the resources allocated to the application during operation by matching the resource requirements to the actual measured application demand; and predict future resource requirements based on planning assumptions related to future application demand.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Non-Provisional application Ser. No. 14/539,973, filed Nov. 12, 2014; U.S. Provisional Application No. 62/077,898, filed Nov. 10, 2014; U.S. Provisional Application No. 62/077,852, filed Nov. 10, 2014; U.S. Provisional Application No. 62/077,860, filed Nov. 10, 2014; and U.S. Provisional Application No. 62/159,883, filed May 11, 2015, the disclosures of each of which are hereby incorporated by reference in their entirety and for all purposes. 
    
    
     Additionally, this application is related to U.S. patent application Ser. Nos. 14/810,284, 14/810,302, and 14/810,357, each filed Jul. 27, 2015, respectively titled “Managing Resources in Container Systems,” “Managing Resources in Computer Systems Using Action Permits,” and “Moving Resource Consumers in Computer Systems,” the entire disclosures of which are incorporated by reference in their entirety and for all purposes. 
     FIELD 
     This specification relates generally to managing resources in virtualization systems, and more specifically, but not exclusively, to the control of such resources based on application demands, to the control of access to such resources, and the management of such resources in a computer-implemented container system. 
     BACKGROUND 
     Traditional computer system architectures typically include one or more dedicated computer servers for each application being run, and are often designed to include an excessive allocation of resources in order to be able to handle peak demands. Such partitioning of computer systems through dedicated servers and excessive allocation of resources can be costly, inefficient and difficult to scale and manage. 
     Virtualization, which refers to the abstraction of computer resources from their hardware or software-based physical constructs, is one manner of dealing with the aforementioned problems. One approach to virtualization is based on one or more virtual machines (VMs), each of which is a software implementation of a computer that executes programs or applications as if it was a physical computer. A virtual machine operates like a physical computer and contains, for example, its own virtual (e.g., software-based) central processing unit (CPU), random access memory (RAM), hard disk storage, and network interface card (NIC). Each virtual machine in a virtualization system generally runs its own guest operating system (OS), and the virtual machines generally share the underlying physical machine resources of the system. 
     Another approach to virtualization is based on one or more containers, each of which is allocated exclusive access to compute resources, using a separate name space, that it may use to execute applications or programs, as if it was a separate operating system. 
     There are many potential benefits to operating in a virtualization system versus traditional architectures. For example, by permitting the sharing of hardware among applications workloads, virtualization can be used for improving resource utilization and reducing the need for excess resources to absorb peak traffic. Virtualization can also be used to improve the availability and robustness of applications, by shifting workloads among servers to handle fail-over situations. Similarly, virtualization provides flexible partitioning of applications, deployment, and operations. Notwithstanding the potential benefits, operating in a virtualization system presents several challenges and potential pitfalls, including significant operations management challenges. 
     For example, virtualization systems perform several input/output (I/O) intensive tasks—often concurrently. When multiple VMs or containers request to execute heavy-storage tasks at the same time (e.g., VM reboots, anti-virus database updates, OS updates, virus scans, and so on), storage controllers can face unrecoverable I/O congestion. 
     Conventional virtualization does not prioritize actions and account for resource impact of such actions. Managing resources in conventional virtualization systems includes evaluating alternative providers for a service or resource by comparing the attributes of the new service or resource and the current one. For example, when considering moving a VM, or a container, to a new storage device or array, conventional virtualization systems often consider the available storage amount and the data access latency of the new storage location, but ignore the time and resources it takes to move the VM, or container, to the new storage location. The impact of moving a VM can become significant when the amount of associated data to move is relatively large. 
     In addition, conventional virtualization systems render decisions based on the immediate impact of performing an action, rather than future impact (e.g., benefits) of an action. The virtualization systems may attempt to take into account a variety of parameters, such as how these parameters have evolved in the past, and how they are likely to evolve in the future. These systems, however, generally make decisions now (for the present time) and do not postpone decisions to the future. Moreover, in the past, predictions of future evolution have historically been rarely accurate. 
     Furthermore, conventional virtualization systems either do not allocate sufficient, or allocate too many, resources to an application that is initially deployed. In some systems, a default configuration is used. However, the default configuration may not be application-specific, may not consider the particular demand profile of the application, and/or cannot account for varying actual demand of the application. In other virtualization systems, modified configurations are based on best practices for an application type and/or artificial load tests in a simulated production environment. A single configuration generally cannot consider all possible application demands, and artificial load tests do not generally reflect with complete accuracy application demands in the production environment. 
     As an additional challenge, once an application is deployed, configurations are generally altered only in response to reported degradation in application performance. Performance metrics are collected and analyzed and the configuration can be manually changed to reflect a user&#39;s understanding of the correlation between the performance degradation and the existing configuration. Unfortunately, the resulting configuration is static and, again, best suited for a single level of demand. If application demand is less than the target of the resulting configuration, the system&#39;s resources will be overprovisioned and result in waste. Alternatively, if application demand exceeds the resulting configuration, the performance of the application is limited. In any case, altering configurations in conventional virtualization systems generally occur only after the application performance has degraded, whereas overprovisioning resources for a particular application is generally not subject to detection. 
     Additionally, current planning techniques for future application demands involve making assumptions about future changes in infrastructure capacity based on historical infrastructure utilization. For example, if the environment is currently utilized at a rate of 50% and the assumption is that application demand will increase by 20% in the next 12 months, then a conclusion is made that the environment will be utilized at a rate of 60% in 12 months. However, these assumptions are generally based on infrastructure changes—not application demand Despite any relationship between application demand and infrastructure utilization, these assumptions are generally not based on actual data and can result in overprovisioning or in limiting resources for a particular application. 
     An alternative virtualization technique can be found in container systems. Container systems provide an operating-system level virtualization in which the kernel of an operating system can allow for multiple isolated user space instances. Stated another way, a container is based on server virtualization that uses a shared operating system. Rather than virtualizing hardware and creating whole virtual machines, each with their own operating systems, containers run atop the shared operating system kernel and file system that looks and feels like a complete, isolated instance of the operating system. Like shipping containers for cargo, these software containers can ship applications across different network-based systems (e.g., cloud computing based systems) and limit the impact of one container&#39;s activities on another container. 
     A container system may include software abstractions to virtualize computer resources (or compute resources) which are used by applications running in the container (“containerized” applications). The container system provides means to provision containers, allocate and control the resources available to a container, deploy and execute applications in the container, and facilitate full use of the container resources by such containerized applications, while isolating them from other applications, sharing the underlying resources. When a containerized application accesses a virtualized container resource (e.g., CPU, memory, storage I/O, Network I/O), the container system maps this access to a direct access of the underlying real resource. 
     Container systems, like virtual machine systems, provide means for abstracting computer resources (or compute resources), controlling and isolating the allocations of these resources to applications, distributing and migrating applications flexibly, among multiple servers, to support scalable, highly-available, robust and efficient datacenter (DC) and cloud systems. Additional information on containers can be found, for example, at Linux Containers (available at https://linuxcontainers.org), http://en.wikipedia.org/wiki/Docker_(software), and https://hadoop.apache.org/docs/r2.4.1/hadoop-yarn/hadoop-yarn-site/YARN.html, each of which is hereby incorporated by reference in its entirety and for all purposes. 
     Since containers are based on shared operating systems, unlike virtual machines, they do not require guest operating systems and thus avoid some of the overhead of virtual machines. For example, deploying and configuring a container may involve setting data structures to map container resources to server and OS resources. Therefore, deploying and configuring a container can often be accomplished in seconds; deploying a virtual machine and a guest OS and configuring both to run an application may require substantially more time. Studies have shown that container-virtualization can offer significant efficiencies and performance advantages over virtual-machines—e.g., see “An Updated Performance Comparison of Virtual Machines and Linux Containers,” by W. Felter et al., IBM Research, Jul. 21, 2014, available at http://domino.research.ibm.com/library/cyberdig.nsf/papers/0929052195DD819C85257D2300681E7B/$File/rc25482.pdf, the disclosure of which is hereby incorporated by reference in its entirety and for all purposes. 
     A virtualization system may mix and match virtual machines and containers. For example, containers may run over virtual-machines. Additionally, a group of virtual machines may be containerized, much like any application, and executed by a container. 
     With lower overheads than VMs, the number of containers sharing a host is often an order of magnitude (e.g., 50-200) larger than the number of VMs (e.g., 5-20). Furthermore, containers perform a faster dynamic of change events (e.g., deploy, delete, increase/reduce resources, and so on). Accordingly, container system management presents challenging scalability and response time problems compared to VMs. 
     In view of the foregoing, a need exists for an improved resource management system and method for container control in an effort to overcome the aforementioned obstacles and deficiencies of conventional virtualization systems. 
     SUMMARY 
     This specification describes new technologies relating to the management of resources and performance in virtualization systems, including container systems and multi-cloud systems. For example, these technologies introduce the use of supply chain economics and other techniques to offer a unified platform to integrate, optimize or improve, and automate resource and performance management in a container system. The economics-based methods can also extend to other virtualization systems for managing application performance. 
     In general, one aspect of the subject matter described in this specification can be embodied in methods and systems that include the actions of determining, for example, by a Container Manager running on a data processor in a container system, a computer resource bundle to be purchased for a container of the container system using virtual currency units; identifying multiple computer servers available to the container system; offering the computer resource bundle; determining a purchase price for the computer resource bundle, in virtual currency units, for each of the identified computer servers; automatically selecting, by the Container Manager, one of the identified computer servers based at least in part on the purchase price for the computer resource bundle set for each of the identified computer servers; and allocating the computer resource bundle from the selected one of the multiple computer servers to the container. Other embodiments of this aspect include corresponding systems, apparatus, and computer program products. 
     Another aspect of the subject matter described in this specification can be embodied in methods and systems that include determining, by a Container Manager running on a data processor in a first container system, a computer resource bundle to be purchased for a container in the first container system using virtual currency units; receiving, from a Proxy Manager of a second container system offering the computer resource bundle, a purchase price for the computer resource bundle in virtual currency units; automatically purchasing the computer resource bundle from the second container system based at least in part on the purchase price received from the Proxy Manager of the second container system; allocating the computer resource bundle from the second container system to the container in the first container system; and dispatching the container from the first container system to execute at the second container system. In some embodiments, dispatching the container includes sending an image of a stateful container to another server or, in the case of stateless containers, initiating a new container on another server and terminating the server on the first server. Other embodiments of this aspect include corresponding systems, apparatus, and computer program products. 
     A further aspect of the subject matter described in this specification can be embodied in methods and systems that include the actions of determining, by a Container Manager running on a data processor in a first container system, a computer resource bundle to be purchased for a container in the first container system using virtual currency units; identifying at least a second container system and a third container system; offering the computer resource bundle at respective purchase prices, in virtual currency units; receiving, from respective Proxy Managers of the second container system and the third container system, a first purchase price for the computer resource bundle for the second container system and a second purchase price for the computer resource bundle for the third container system; automatically selecting one of the second container system and the third container system based at least in part on the respective purchase prices for the computer resource bundle for the second container system and the third container system; and allocating the computer resource bundle from the selected one of the second container system and the third container system to the container in the first container system. Other embodiments of this aspect include corresponding systems, apparatus, and computer program products. 
     Still another aspect of the subject matter described in this specification can be embodied in methods and systems that include the actions of allocating a computer resource bundle to an application executed by a container system; determining, by an Application Element Manager running on a data processor in the container system, the value of a service level agreement parameter for the application based on the allocated computer resource bundle; comparing the determined service level agreement parameter level for the application to a threshold service level agreement parameter level; automatically modifying the allocation of computer resources to the application depending on whether the identified service level agreement parameter level for the application is below or above the threshold service level agreement parameter level; and repeating the determining, comparing and automatically modifying steps until the operation of the application in the container system is suspended or terminated. Other embodiments of this aspect include corresponding systems, apparatus, and computer program products. 
     Yet another aspect of the subject matter described in this specification can be embodied in methods and systems that include the actions of purchasing a computer resource bundle, using virtual currency units, for an application running at a container in a container system; allocating the purchased computer resource bundle to the application; determining, by a Container Manager running on a data processor in the container system, the value of a service level agreement parameter for the application; automatically modifying the purchase of the computer resource bundle based at least in part on a comparison of the determined value of a service level agreement parameter to a predetermined threshold service level agreement parameter level; and repeating the determining, comparing and automatically modifying steps until the operation of the application in the container system is suspended or terminated. Other embodiments of this aspect include corresponding systems, apparatus, and computer program products. 
     Another aspect of the subject matter described in this specification can be embodied in methods and systems that include network-aware placement of containers to minimize input/output (I/O) latency. Some methods include the actions of determining a target I/O latency metric, for storage or network communications of an application running in a container system; determining, by a container manager, a first I/O pathway that meets the target latency and an amount of I/O bandwidth, over the first I/O pathway, to be acquired for the container; allocating the determined amount of I/O bandwidth, over the determined first I/O pathway to the application; automatically allocating the determined amount of I/O bandwidth to the application, from the second I/O pathway, based at least in part on the determined I/O bandwidth utilization of the first I/O pathway. Other embodiments of this aspect include corresponding systems, apparatus, and computer program products. 
     Another aspect of the subject matter described in this specification can be embodied in methods and systems that include the actions of determining, by a Container Manager running on a data processor in a container system, an amount of input/output (I/O) bandwidth—for example, for storage or network communications—to be acquired for a container of the container system; identifying at least a first computer server and a second computer server in the container system, each offering at least the determined amount of I/O bandwidth; allocating, from the first computer server, the amount of I/O bandwidth to the container; determining the I/O bandwidth utilization of the first computer server; automatically allocating the amount of I/O bandwidth to the container, from the second computer server, based at least in part on the determined I/O bandwidth utilization of the first computer server. Other embodiments of this aspect include corresponding systems, apparatus, and computer program products. 
     Yet another aspect of the subject matter described in this specification can be embodied in methods and systems that include the actions of determining, by a Container Manager running on a data processor in a container system, an amount of I/O bandwidth—for example, for storage or network communications—to be acquired from a first computer server for a container running on the first computer server; allocating, from the first computer server, the amount of I/O bandwidth to the container for a first period of time; after the first period of time has elapsed, determining that the I/O bandwidth utilization of the first computer server is greater than a threshold limit; automatically identifying at least a second computer server in the virtualization system offering at least the determined amount of I/O bandwidth of the first computer server; moving the container from the first computer server to the identified second computer server; and allocating from the second computer server, the determined amount of I/O bandwidth, to the container, for a second period of time. Other embodiments of this aspect include corresponding systems, apparatus, and computer program products. 
     Yet another aspect of the subject matter described in this specification can be embodied in methods and systems for fractional resource allocation that include the actions of determining, by a Container Manager running on a data processor in a container system, a resource bundle to be acquired from a first computer server for a container running on the first computer server; allocating, from the first computer server, the determined resource bundle for a first period of time; after the first period of time has elapsed, determining that the utilization of the first computer server exceeds a threshold limit; determining the excess resources corresponding to the excess utilization; automatically identifying a second computer server to replicate the container; replicating the container at the identified second computer server; allocating from the identified second computer server, a resource bundle equal or lower than the determined excess resources, to the replicated container, for a second period of time. Other embodiments of this aspect include corresponding systems, apparatus, and computer program products. 
     Yet another aspect of the subject matter described in this specification can be embodied in methods and systems that include the actions of determining, by a Container Manager running on a data processor in a container system, an amount of I/O bandwidth—for example, for storage or network communications—to be acquired from a first computer server for a container running on the first computer server; allocating, from the first computer server, the amount of I/O bandwidth to the container for a first period of time; after the first period of time has elapsed, determining that the I/O bandwidth utilization of the first computer server exceeds an I/O bandwidth threshold limit; determining the excess I/O bandwidth corresponding to the excess I/O bandwidth utilization; automatically identifying a second computer server in the container system to replicate the container; allocating from a second computer server, an amount of I/O bandwidth equal or lower than the determined excess I/O bandwidth, to the replicated container, for a second period of time; and using a Load Balancer to divide the processing of I/O bandwidth between the container, at the first computer server, and the replicated container at the second computer server. Other embodiments of this aspect include corresponding systems, apparatus, and computer program products. 
     Still another aspect of the subject matter described in this specification can be embodied in methods and systems that include the actions of determining, by an Application Element Manager running on a data processor in a container system, a software license to be purchased using virtual currency units by an application operating in the container system; determining, by a Licensing Element Manager running on the data processor, the number of copies of the software licenses available for purchase in the container system; determining, by the Licensing Element Manager, the purchase price for a copy of the software license; automatically purchasing, by the Application Element Manager, a copy of the software license for the application based at least in part of the determined purchase price for a copy of the software license; and allocating the purchased copy of the software license to the application. Other embodiments of this aspect include corresponding systems, apparatus, and computer program products. 
     A further aspect of the subject matter described in this specification can be embodied in methods and systems that include the actions of allocating, from a computer server in a container system, a computer resource bundle to a container operating in the container system; determining, by a Container Manager running on a data processor in the container system, a productivity score of the container; determining that the productivity level of the container is below a threshold productivity level; and automatically initiating, by the Container Manager, at least one of a suspension sequence and a termination sequence for the container based at least in part on the determination that the productivity level of the container is below a threshold level. Other embodiments of this aspect include corresponding systems, apparatus, and computer program products. 
     Another aspect of the subject matter described in this specification can be embodied in methods and systems that include the actions of allocating a computer resource bundle to a computer server operating in a container system; determining, by a Computer Server Element Manager running on a data processor in the container system, a productivity score of the computer server; determining that the productivity level of the computer server is below a threshold productivity level; and automatically initiating, by the Computer Server Element Manager, at least one of a suspension sequence and a termination sequence for the computer server based at least in part on the determination that the productivity level of the computer server is below a threshold level. Other embodiments of this aspect include corresponding systems, apparatus, and computer program products. 
     Yet another aspect of the subject matter described in this specification can be embodied in methods and systems that include the actions of determining a computer resource bundle to be purchased for a containerized container running at a parent container in a container system; purchasing the determined computer resource bundle; and allocating the purchased computer resource bundle to the containerized container. Other embodiments of this aspect include corresponding systems, apparatus, and computer program products. 
     As further discussed herein, the subject matter includes methods to place containers at hosts and allocate computer resources (or compute resources) to the containers based on a supply-chain marketplace for buying/selling resources; migrate containers to hosts based on purchasing resources in a supply chain marketplace; automatically replicate an overloaded container, allocate resources to the replicated containers, and partition the container workload among its replicated containers; automatically replicate an overloaded container, allocate resources to the replicated containers, and partition the I/O stream among the replicated containers using a load balancer; allocate resources to containers to handle the workload of an application and assure a target Service Level Agreement (SLA) performance metric; allocate software licenses to applications running in containers; and select a production system and to dispatch a container from a development system to a production system; assign a productivity score to a host running a container system, based on its virtual Profit and Loss (P&amp;L) performance, remove containers from a host with low productivity and set it into standby mode, or shut it down to save electricity. Respective methods to shift a host from standby mode to execute containers systems, when the productivity score is sufficiently high, are also disclosed. 
     As also discussed herein, the subject matter further includes methods to place highly communicating containers “close” to one another to minimize their I/O latency and maximize its bandwidth. In some embodiments, “close” can be measured by the number of switches along the I/O pathway. Additional subject matter disclosed includes methods to cluster containers with related applications into container points of delivery (cPODs) and migrate an entire cPOD between clouds through an atomic action. Further disclosure includes methods and systems to containerize a container to create a supply chain hierarchy of nested containers and use it to provide scalable resource allocation whereby a parent container “sells” its resources, using virtual currency, to its daughter containers. 
     These and other embodiments can optionally include one or more of the following features. Virtual currency units can be used to control the purchase of computer resources. Computer resources can be allocated in the event a budget of the acquiring computer element is sufficient. The allocation of computer resources can be in exchange for the payment of virtual currency units. Virtual currency units can be converted into real currency, such as United Stated dollars, or euros. A performance metric of an application executing in a container can be determined, and the allocation of computer resources is based on such performance metric. A performance metric of an application executing in a container can be determined, and the allocation of virtual currency units to the application or the container can be based on such performance metric. The computer resources to be allocated can include at least one of an allotment of computer memory, an allotment of program execution scheduling for one or more central processing units, an allotment of storage interface bandwidth, an allotment of network or I/O interface bandwidth, and an allotment of a storage array. 
     Additionally, according to various embodiments, a computer resource provider can be selected based on the price offered for the computer resources. The price offered for the computer resources can be determined by an auction process, or by the utilization of the computer resources (e.g., congestion pricing), or by a service level metric provided by the resources, or by the cost of the resource, or any combination of these and other pricing factors. The amount of computer resources purchased can be dependent on a computed computer resource utilization. A proxy manager of a second container system optionally controls the allocation of computer resources to a first container system. The foregoing features are optional and not exhaustive, and they may be separately realized or realized in various combinations. 
     Moreover, particular embodiments of the subject matter described in this specification can be implemented to realize one or more of the following advantages. Computing resources may be monitored and managed in container systems based on economic and non-economic principles, both in single-cloud and multi-cloud systems. Such management of resources may be used to control the delivery of service level agreements, and the distribution of software licenses, in container systems. They also may be used to suspend or terminate computing resources in container systems. These advantages and features are optional and not exhaustive, and they may be separately realized or realized in various combinations. 
     Another aspect of the subject matter described in this specification can be embodied in systems and methods that assure application performance by matching the supply of resources (e.g., application resources, VM resources, or physical resources) with the fluctuating demand placed on the application. For example, the systems and methods disclosed herein can be used to ensure that the application is allocated sufficient resources when it is initially deployed to handle anticipated demand; dynamically alter the resources allocated to the application during operation by matching the resource requirements to the actual measured application demand; and predict future resource requirements based on planning assumptions related to future application demand. 
     In some embodiments, the systems and methods described herein apply to applications that scale vertically—e.g., to scale the additional resources that are allocated to the existing application components. Additionally and/or alternatively, the systems and methods described herein apply to applications that scale horizontally. Horizontally scaling applications are scaled by provisioning additional application components and dividing the work to be done among the old and new components (compared to adding resources to existing components). 
     In one embodiment, the application component that horizontally scales buys additional resources from a new provider (e.g., virtual server)—rather than the current provider—and is provisioned along with a new application component. The new application component can purchase the required resource from the new provider. Conversely, if the application component can no longer afford the resources, the provider and the application component can be decommissioned. Alternatively, if the application component can no longer afford the resources, the resources can be removed. 
     In some embodiments, the system can be used in real time in order to efficiently allocate the required resources to applications based on a balance of supply and demand. The system is able to scale an application either vertically (reconfigure) or horizontally (auto-scale) such that more detailed control can be achieved by considering target Quality of Service (QoS) metrics such as transactions throughput rate or transaction response time targets defined for these measures. These targets represent the desired service level of the application. The application may perform below its desired service level and not achieve the defined targets for these QoS metrics. If the application achieves the target, it is considered to perform at its desired service level. An application that is below its desired service level can be brought into compliance by either adding more resources (vertical scale) or more application components (horizontal scale). 
     The ability of an application to buy resources is a function of its revenue and the expenses based on the price of the resources. In the scenario where an application is below its desired service level, the system can allocate additional budget to the application, providing a greater power to buy resources. Therefore, QoS metrics can be used to gain additional granularity in the allocation of resources. 
     In other embodiments, the system can also be used when deploying new applications in order to determine the required or preferred resource allocation. By simulating application demand (e.g., transactions), the system can determine the required or preferred number of application components and the appropriate allocation of resources. 
     Additionally and/or alternatively, the system can be used when planning for future application needs. By simulating future application demand (e.g., transactions), the system can determine the required number of application components and the appropriate allocation of resources. 
     Moreover, particular embodiments of the subject matter described in this specification can be implemented to realize one or more of the following additional advantages. Computing resources may be monitored and managed in virtualization systems based on economic and non-economic principles, both in single-cloud and multi-cloud systems. Such management of resources may be used to control the delivery of service level agreements, and the distribution of software licenses, in virtualization systems. They may also be used to suspend or terminate computing resources in virtualization systems. These advantages and features are optional and not exhaustive, and they may be separately realized or realized in various combinations. 
     As also discussed herein, the subject matter further includes methods relating to the management of resources in virtualization systems, including multi-cloud systems. These technologies introduce the use of economic-based cost analysis, and other techniques to offer a comprehensive framework to manage the number and rate of actions and prioritize resource management in a virtualization system. 
     Moreover, particular embodiments of the subject matter described in this specification can be embodied in methods and systems that regulate access of consumers (e.g., applications, containers, or VMs) to resources and services (e.g., storage). In one embodiment, this regulation occurs through the use of access or action permits, referred to as permits that the consumer acquires from an intermediate entity—an Action Manager (AM)—prior to accessing the resource or service. Regulating access includes, for example, controlling one or more of the number of concurrent accesses to a particular resource, the rate at which consumers access the resource, the total number of consumers in a group of consumers accessing the resource, and the total rate at which a group of consumers accesses a resource. According to various embodiments, similar regulation is applied to a group of resources (rather than a single resource). 
     In some embodiments, there can be one type of permit per provider. The AM can sell multiple types of permits, regulating access to a number of resources. Each permit can be associated with a predetermined price. Additionally and alternatively, this price can be dynamically adjusted, for example, taking into consideration the availability of permits the AM possesses. Other embodiments of this aspect include corresponding systems, apparatus, and computer program products. 
     In another embodiment of the invention, the consumer acquires the permits from the resource or service itself. 
     Another aspect of the subject matter described in this specification can be embodied in methods and systems that formulate and evaluate the option to move a consumer to a new provider. According to various embodiments, “formulating” can include the attributes taken into account when considering the option to move to the new provider. The cost of moving can be part of the comparison between two or more alternatives (e.g., keeping a VM in an existing infrastructure or moving the VM to an external cloud provider). Cost can be expressed in actual currency or any unit suitable for the comparison. For example, moving time can be expressed in a real value that quantifies the cost of the VM downtime. In contrast, if there is a strict limit on acceptable downtime, the cost of moving the VM can be expressed in terms of a cost metric of downtime. 
     According to various embodiments, “evaluating” includes making the decision (e.g., initiating an action based on the decision) and determining the right time to take the action. Compared to other economics-based decision-making systems, one embodiment described herein postpones the decision for the future, advantageously waiting for a sufficient amount of time until the decision-maker is convinced that the decision is the right one. Other embodiments of this aspect include corresponding systems, apparatus, and computer program products. 
     Moreover, particular embodiments of the subject matter described in this specification can be implemented to realize one or more of the following advantages. Computing resources may be monitored and managed in virtualization systems based on economic and non-economic principles, both in single-cloud and multi-cloud systems. Such management of resources may be used to control the delivery of service level agreements based on access control, and the distribution of software licenses, in virtualization systems. They may also be used to suspend or terminate computing resources in virtualization systems. These advantages and features are optional and not exhaustive, and they may be separately realized or realized in various combinations. 
     Another aspect of the subject matter described in this specification can be embodied in methods and systems that include determining, by an application manager running on a data processor in a virtualization system that runs at least one guest operating system, a computer resource bundle to be purchased, using virtual currency units, for an application running on a virtual machine in the virtualization system; allocating the computer resource bundle from a computer server in the virtualization system to the application; and initiating, following an increase in the purchase price for the allocated computer resource bundle, a credit check process by the application manager, wherein the credit check process results in an increase in budget of virtual currency units available for usage by the application, wherein the virtual machine is a software implementation of a computer that runs at least one guest operating system and executes one or more applications on the guest operating system. 
     In some embodiments, the methods and systems further include receiving, from a proxy manager of a second virtualization system offering the computer resource bundle, a purchase price for the determined computer resource bundle in virtual currency units, wherein the second virtualization system also runs at least one guest operating system; determining, following initiation of the credit check process, whether the determined computer resource bundle is to be purchased from a second computer server in the second virtualization system based at least in part on the purchase price received from the proxy manager of the second virtualization system; and allocating the computer resource bundle from the second computer server in the second virtualization system to the application. 
     In some embodiments, the methods and systems further includes maintaining a budget, in virtual currency units, for the application; determining whether the budget of virtual currency units for the application is sufficient to pay the purchase price for the computer resource bundle; allocating the computer resource bundle to the application only if the budget of the application has been determined to be sufficient to pay the purchase price for the computer resource bundle; and transferring virtual currency units from the budget for the application to a budget for the computer server based on the purchase price for the computer resource bundle determined for the computer server. 
     In some embodiments, the computer resource bundle includes one or more computer resources, the method further includes determining a performance metric level of the application; and adjusting the allocation of at least one of the one or more computer resources to the application based on a comparison of the determined performance metric level to a predetermined threshold performance metric level. 
     In some embodiments, the performance metric level of the application is correlated to at least one of the transaction rate for the application, the number of transactions performed by the application, and the completion time or delay for the application. 
     In some embodiments, the computer resource bundle includes one or more computer resources, the method further includes determining a performance metric level of the application; and adjusting a budget of virtual currency units for the application based on a comparison of the determined performance metric level to a predetermined threshold performance metric level. 
     In some embodiments, the computer resource bundle includes at least one of an allotment of computer memory, an allotment of program execution scheduling for one or more central processing units, an allotment of storage interface bandwidth, an allotment of network interface bandwidth, and an allotment of a storage array. 
     In some embodiments, allocating the computer resource bundle from the computer server to the application comprises moving the application to a second computer server. 
     In some embodiments, the allocated computer resource bundle includes at least a first computer resource and a second computer resource, the method further comprising de-allocating the first computer resource based at least in part on a comparison of a determined usage of the first computer resource to a determined usage of the second computer resource. 
     In some embodiments, the computer resource bundle includes multiple computer resources, and wherein the determining a computer resource bundle to be purchased is based at least in part on a computed utilization of one of the multiple computer resources. 
     In some embodiments, the method further includes increasing the amount of the computer resource bundle to be purchased if it is determined that the computed utilization of the one of the multiple computer resources is below a predetermined threshold. 
     In some embodiments, the method further includes decreasing the amount of the computer resource bundle to be purchased if is determined that the computed utilization of the one of the multiple computer resources is above a predetermined threshold. 
     In some embodiments, the determining a purchase price for the computer resource bundle includes receiving one or more auction bids for purchase of the computer resource bundle. 
     In some embodiments, the methods and systems further include converting virtual currency units to government issued monetary currency based on a predetermined exchange rate. 
     Another aspect of the subject matter described in this specification can be embodied in methods and systems for regulating access to computer resources, comprising: a computer-based virtualization system that runs at least one guest operating system; and instructions stored on a non-transitory computer readable medium in the virtualization system and executable by a data processing apparatus to cause the data processing apparatus to perform operations comprising: determining, by an application manager running on a data processor in a virtualization system that runs at least one guest operating system, a computer resource bundle to be purchased, using virtual currency units, for an application running on a virtual machine in the virtualization system, allocating the computer resource bundle from a computer server in the virtualization system to the application; and initiating, following an increase in the purchase price for the allocated computer resource bundle, a credit check process by the application manager, wherein the credit check process results in an increase in budget of virtual currency units available for usage by the application, and wherein the virtual machine is a software implementation of a computer that runs at least one guest operating system and executes one or more programs or applications on the guest operating system. 
     In some embodiments, the operations further include receiving, from a proxy manager of a second virtualization system offering the computer resource bundle, a purchase price for the determined computer resource bundle in virtual currency units, wherein the second virtualization system also runs at least one guest operating system; determining, following initiation of the credit check process, whether the determined computer resource bundle is to be purchased from a second computer server in the second virtualization system based at least in part on the purchase price received from the proxy manager of the second virtualization system; and allocating the computer resource bundle from the second computer server in the second virtualization system to the application. 
     In some embodiments, the operations further include maintaining a budget, in virtual currency units, for the application; determining whether the budget of virtual currency units for the application is sufficient to pay the purchase price for the computer resource bundle; allocating the computer resource bundle to the application only if the budget of the application has been determined to be sufficient to pay the purchase price for the computer resource bundle; and transferring virtual currency units from the budget for the application to a budget for the computer server based on the purchase price for the computer resource bundle determined for the computer server. 
     In some embodiments, the operations further include determining a performance metric level of the application; and adjusting a budget of virtual currency units for the application based on a comparison of the determined performance metric level to a predetermined threshold performance metric level. 
     In some embodiments, the computer resource bundle includes at least one of an allotment of computer memory, an allotment of program execution scheduling for one or more central processing units, an allotment of storage interface bandwidth, an allotment of network interface bandwidth, and an allotment of a storage array. 
     In some embodiments, allocating the computer resource bundle from the computer server to the application comprises moving the application to a second computer server. 
     In some embodiments, the allocated computer resource bundle includes at least a first computer resource and a second computer resource, the instructions further causing the data processing apparatus to de-allocate the first computer resource based at least in part on a comparison of a determined usage of the first computer resource to a determined usage of the second computer resource. 
     Additional details of one or more embodiments of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the descriptions contained herein, the drawings, and the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of an example container environment in which resources are managed. 
         FIG. 2  is a block diagram of an example software system for managing resources in a container system. 
         FIG. 3  is a flow diagram of an example process for using a platform manager in a container system. 
         FIG. 4  is an example model for service provision and consumption in a supply chain container system. 
         FIG. 5  is a flow diagram of an example process for deploying a new consumer element with a provider element in a container system. 
         FIG. 6  is a flow diagram of an example process for delivering service level agreement targets through resource allocation in a container system. 
         FIG. 7  is a flow diagram of an example process for economic-based I/O scheduling in a container system. 
         FIG. 8A  is an example purchase order data structure for use in purchasing services from a provider element manager in a container system. 
         FIG. 8B  is an example service confirmation data structure for use in confirming or rejecting the purchase of services from a provider element manager in a container system. 
         FIG. 9  is an example process for managing the states of system elements in a container system. 
         FIG. 10  is a block diagram of an example multi-domain software system environment for managing virtualized resources. 
         FIG. 11  is a block diagram of an example virtualization environment which illustrates supply chain relationships between service entities and resources. 
         FIG. 12  is a block diagram of another example virtualization environment which illustrates supply chain relationships between service entities and resources in a container system. 
         FIG. 13  is a flow chart illustrating a process for resource scaling in the virtualization environment of  FIG. 11 . 
         FIG. 14  is a flow chart illustrating a process for service entity scaling in the virtualization environment of  FIG. 11 . 
         FIG. 15  is a block diagram of yet another example virtualization environment which illustrates the supply chain relationships between service entities and resources in a virtualization environment and can cooperate with the processes described in  FIGS. 13-14 . 
         FIG. 16  is a block diagram of an example virtualization environment in which resources are managed by an action manager. 
         FIG. 17  is a block diagram illustrating the data flow for managing resources in the virtualization environment of  FIG. 16 . 
         FIG. 18  illustrates an exemplary block diagram of a virtualization environment in which a virtual machine is determining whether to take an action. 
     
    
    
     Like reference numbers and designations in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
       FIG. 1  is a block diagram of an example container system or environment  100  in which resources are managed. The example system  100  includes two servers  102  and  104  that run respective container systems  110  and  112 . The container system  110 , at the server  102 , allocates computer resources (or compute resources) of the server  102 —e.g., CPUs, memories, storage volume, storage, and/or network I/O pathways and bandwidth—to two containers  120  and  122 . Similarly, the container system  112  at the server  104  allocates resources of the server  104  to containers  124  and  126 . The containers  120 ,  122 ,  124  and  126  execute respective containerized applications  130 ,  132 ,  134 , and  136 . 
     As previously discussed, container systems admit flexible organizations. In the example system  100 , the servers  102  and  104  may be physical machines with physical computer resources (or compute resources). Alternatively, the server  102  may be a virtual machine with virtualized resources while the server  104  is a physical server. The containers  120 ,  122 ,  124  and  126  may be distinct containers, or replicated copies of a single container. In some embodiments, a group of containers may be clustered into a container-Point-of-Delivery (cPOD) system, to run related applications. For example, a multi-tier Web service may include a containerized Web server (shown as the application  130 ), a containerized application server (shown as the application  134 ), and a containerized database server (shown as the application  136 ). The Web server provided by the application  130  can maintain significant level of communications with the application server provided by the application  134 . The I/O pathway between the applications  130 ,  134  traverses the application  130 , the container  120 , the container system  110 , an operating system  106 , a network interface card (NIC)  140 , a data network  160 , a NIC  142 , an operating system  108 , the container system  112 , the container  124 , and the application  134 . 
     In this example, the portion of the aforementioned I/O pathway that includes the NIC  140 , the data network  160 , and the NIC  142  traverses network switches and links, and can thus result in significant I/O latency as well as bandwidth limitations. A container manager  236 —considered below and shown, for example, in  FIG. 2 —can migrate (ship) the container  120 , with the application  130 , from the server  102  to the server  104 . This migration replaces the I/O pathway from the application  130  to the application  134  with a pathway that includes the application  130 , the container  120 , the container system  112 , the operating system  108 , the container system  112 , the container  124 , and the application  134 . Advantageously, this modified I/O pathway entirely can be handled by the server  104  through memory transfers. This in-memory I/O pathway can support very high memory transfers bandwidth and very low latency, thus, improving the cPOD performance. 
     Although a specific environment  100  including the two servers  102  and  104  is shown in  FIG. 1  and described above, it will be understood that the environment  100  is illustrative only. For example, the environment  100  may include more than two servers, and each of the servers  102  and  104  may be associated with any number of containers as desired. 
     The principles described herein may be applied regardless of the particular application or applications being run in the container system. 
       FIG. 2  is a block diagram of an example software system  200  for managing resources in container systems, such as the container system  100 . According to various embodiments, the software system  200  may be used to allocate server and I/O resources (such as CPU, memory, flash storage, hard drive storage and I/O bandwidth) to containers. The software system  200  also may be used, for example, to monitor, detect, and handle congestion conditions at a resource (e.g., I/O pathway, memory, and so on) and to move containers among available servers to optimize or improve application performance and resource utilization. 
     The software system  200  monitors, controls, and otherwise interacts with various managed container system elements (also referred to herein as service elements or computer elements) through respective instrumentation. As used herein, in the context of computers, the term “instrumentation” refers generally to any software and/or hardware that provides an ability to monitor, control, or otherwise interact with a computer element, such as to detect operations events, reconfigure parameters, diagnose errors, and write trace information. For example, when a computer application contains instrumentation code, the computer application may be managed using a management tool. 
     Several example container system elements are shown in  FIG. 2  as part of an Information Technology (IT) Container Stack (ITCS)  202 , including applications components  210 , container systems  212 , servers  214 , storage systems  216 , networks  218 , and operating resources  220  (such as power supplies, cooling systems, and rack space). In some embodiments, the ITCS  202  may include, for example, a proper subset or a proper superset of these container system elements  210 ,  212 ,  214 ,  216 ,  218 , and  220 . 
     As shown, the software system  200  includes a platform layer  230 , which provides an infrastructure to manage, for example, the I/O flows in a container system (such as the example container system environment  100  shown in  FIG. 1 ). The platform layer  230  includes element managers  234 ,  236 ,  238 ,  240 ,  242 , and  244 . More particularly, the platform layer  230  includes an application manager  234 , a container system manager  236 , a server manager  238 , a storage manager  240 , a network manager  242 , and an operations manager  244 . These element managers  234 ,  236 ,  238 ,  240 ,  242 , and  244  use management instrumentation of respective elements to monitor and control the respective elements of the ITCS  202 . 
     For example, the server manager  238  may use built-in management instrumentation, such as Management Information Bases (MIBs) of the server it is managing, to monitor the server&#39;s CPU, memory, and I/O interfaces (such as a Host Bus Adapter (HBA) and NICs) and to control their operational parameters. The server manager  238  may access such management instrumentation using standardized protocols (such as Simple Network Management Protocol (SNMP)) or specialized mechanisms. In some embodiments, a proper superset or only a proper subset of these element managers  234 ,  236 ,  238 ,  240 ,  242 , and  244  may be desired or needed in certain environments. For example, when the containers do not access storage, the use of a storage manager  240  may not be needed. Additionally, for example, an operating system element manager (not shown) may be included as part of platform layer  230 . 
     As also shown, the platform layer  230  also includes one or more types of modeling databases  245 . As discussed in more detail below, the databases  245  may include supply chain modeling (SCM) databases  246  and operations databases  248 . The platform layer  230  also includes a platform manager  250 , which, as explained in greater detail below, can be responsible for general provisioning, initializing, and management tasks. 
     The software system  200  shown in  FIG. 2  also includes a functional management layer  252 , which includes user interface (UI) software  260  for use by administrators or other users to monitor and control a container system (such as the example container system environment  100  shown in  FIG. 1 ). For example, an administrator may use the UI software  260  to set proactive automation policies to optimize or improve performance and resource utilization, detect and resolve operational problems and performance bottlenecks, allocate priorities and usage charges to different applications, and plan capacity expansions. 
     The functional management layer  252  also includes a collection of functional managers  272 ,  274 ,  276 , and  278 , which are used to enable users to monitor, control, and automate the underlying automated management mechanisms of container systems according to the principles described herein. The software system  200  may alternatively include, for example, a proper subset or a proper superset of these functional managers. 
     As shown in  FIG. 2 , the functional management layer  252  includes an application manager  272 , which, for example, enables users to select or configure respective parameters of a computer agent or process to partition application components among different containers, allocates virtual budgets to applications based on the business value of their services, as described in greater detail below, and specifies the resources required by the applications. The application manager  272  uses the parameters to create respective records in the operations databases  248 . The platform manager  250  uses the operations records to initialize respective application managers  234 , which use the operations records to deploy the applications  210 , according to the principles described below. Additional functions of monitoring and controlling applications may be incorporated into the application manager  272 . 
     The functional management layer  252  also includes a performance manager  274 , which allows users to monitor and control the delivery of Service Level Agreements (SLAs) to applications. For example, a user of the software system  200  can specify target SLA parameters—such as latency or transaction rate—of one or more particular applications. The SLA parameters are used by the software system  200  to adjust the performance of the applications using the principles described below. A user can also monitor the SLA parameters value, as well as the respective virtual payments made by an application, thereby correlating the application&#39;s budget with its SLA performance. Additional functions of monitoring and controlling the performance of applications, as well as the other elements of the ITCS  202 , may be incorporated into the performance manager  274 . 
     A capacity manager  276  monitors relationships between the supply and demand of resources in the ITCS  202 . For example, the capacity manager  276  may monitor the relationships over a predetermined time period, which can range from short term (such as a few minutes or one hour) to long term (such as one day, week, month or year). In some embodiments, the capacity manager  276  maintains full accounting of revenues and costs and provides monitoring of these accounts and notifications upon certain accounting events. The capacity manager  276 , by itself or with the assistance of an incorporated or separate Return-on-Investment (ROI) manager (not shown), enables a user to monitor the ROI of the elements in the ITCS  202 . The ROI is defined as revenue divided by cost, where revenue is the income from virtual payment collected by a selected element and cost is the virtual payments by the element for the resources that the element uses. 
     For example, a large ROI may indicate to the capacity manager  276  that there is excess demand over supply of the element capacity, and a sustained high ROI may thus indicate insufficient capacity. The capacity manager  276  compares a monitored ROI with specific and potentially predetermined ROI targets, which may be configured by an administrator or other user, to recommend capacity increases of particular elements to meet demand According to the supply chain economic principles described below, the ROI of an element in the ITCS  202  may be considered as a central metric of economic value. 
     The ROI may be calculated at any appropriate time and for any appropriate duration over which revenue and cost are considered. Thus, the principles described herein provide an accounting framework to quantify and measure the value generated by components of the ITCS  202 . For example, at the bottom of the ITCS  202 , there are raw resources that generate real (non-virtual) costs, such as monetary costs that are paid to an electric company. At the top of the ITCS  202 , there are applications that play roles in generating real (non-virtual) revenues, such as monetary sales revenue received from customers. It is possible to treat one or more of the system elements  210 ,  212 ,  214 ,  216 ,  218 , and  220  as virtual Profit and Loss (P&amp;L) entities, generating revenues through payments by its consumers, and paying the costs of services it consumes. The use of virtual currency pricing and payments, as described herein, to distribute a share of these revenues to cover costs increases the efficiency and overall ROI of the entire system. 
     A back-charging manager  278  monitors and accounts for the virtual cash flows between elements in the ITCS  202  and enables users to flexibly compute financial metrics of interest. For example, users can monitor metrics describing the allocation of application budgets to acquire supply chain resources, the allocation of a resource among the workloads of different applications, the ROI efficiency of different resources, and application budgets required to deliver particular SLAs. These metrics and other parameters may be used to support policies on budgeting applications, adjusting the budgets to represent changing prices, capacity, and demand of resources along the supply chain, and converting virtual currency used within the software system  200  to real currency (such as United States dollars, or euros) that is generated by the business units who own the applications and that may be used to pay for IT resources. 
     The platform manager  250  can manage a container system using any suitable means described herein, including using a process  300  as shown in  FIG. 3 . Turning to  FIG. 3 , a flow diagram of the example process  300  for using the platform manager  250  in a container system (such as the container system  100 ) is shown. According to various embodiments which implement process  300 , the platform manager  250  initializes, or launches, the functional managers  272 ,  274 ,  276  and  278  of the functional management layer  252  for a specific container environment (step  302 ). The platform manager  250  discovers the managed container system elements of the ITCS  202  in the container environment (step  304 ). This discovery is handled, for example, through standard processes to get configuration data from the container system, OS, server, network, and storage systems. 
     The platform manager  250  also initializes, or launches, an element manager (such as one or more of element managers  234 ,  236 ,  238 ,  240 ,  242 , and  244 , described above) for each group of respective elements of a given class of elements that have been discovered (step  306 ). For example, the platform manager  250  may detect a Dell® server and a SUN® server, and the corresponding groups of respective elements may both be assigned respective element managers. The platform manager  250  configures the element managers to monitor and control the respective elements via respective management instrumentation. 
     The platform manager  250  populates and initializes the platform modeling databases  245 —for example, the supply chain modeling databases  246  and the operational databases  248  (step  308 )—and starts monitoring certain potential changes of the managed environment (step  310 ). For example, the container system  100  may be monitored to determine if there have been any container changes, such as any added, deleted, or migrated container (decision block  312 ). If a container change has been detected, the platform manager  250  again initializes the element managers as described above. 
     If no container changes have been detected, the presence of container systems is evaluated to determine if there have been any container system changes, such as any added or deleted container system (decision block  314 ). If a container system change has been detected, the platform manager  250  again discovers the managed container system elements of the ITCS  202  in the container environment as described above. Otherwise, the platform manager  250  evaluates whether there have been any major network changes (decision block  316 ), in which case the platform manager  250  similarly re-discovers the managed container system elements of the ITCS  202  in the container environment as described above. For example, the platform manager  250  may discover loss or gain of network I/O pathways, congestion or under-utilization of an I/O pathway, low or excessive latency of an I/O pathway, or packet losses along an I/O pathway. Otherwise, the platform manager  250  evaluates whether there have been any major storage changes (decision block  318 ). For example, the platform manager  250  may discover storage I/O congestion, or alternate I/O pathways that would provide better (i.e., lower) access latency. If major storage changes have been detected, the platform manager  250  again discovers the managed container system elements of the ITCS  202  in the container environment as described above. 
     If no container, container system, network, or storage changes have been detected, the platform manager  250  determines whether to continue monitoring of the same (decision block  320 ). If the platform manager  250  decides to continue monitoring, the platform manager  250  again starts the monitoring of potential changes of the managed environment. Otherwise, the process  300  ends (end block  322 ). 
     The order of steps in the example process  300  described above is for illustration purposes only, and can be done in different orders. For example, the platform manager  250  may evaluate whether there has been any major storage changes (decision block  318 ) before determining whether there has been any major network changes (decision block  316 ). Moreover, additional steps may be included, for example, to protect the software system  200  against its own failures. Such additional steps may include, for example, inserting between steps  308  and  310  described above the steps (not shown) of creating a mirror and backup copies of the platform image (including the databases  246  and  248 ), running a second instance of the software system  200  in standby mode and monitoring the primary instance of the software system  200 , and switching to the standby instance of the software system  200  upon detecting the failure of the first instance of the software system  200 . 
     According to various embodiments, the software system  200  described above can operate using a supply chain software model of the ITCS  202  that it manages. In other words, each container system element  210 ,  212 ,  214 ,  216 ,  218 , and  220  of the ITCS  202  is modeled as a provider and a consumer of services. For example,  FIG. 4  is an example model  400  for service provision and consumption in a supply chain container environment. According to various embodiments as shown in  FIG. 4 , which includes references to the container system elements of the ITCS  202  shown in  FIG. 2 , the server  214  may consume services of the operating resources  220 , including, for example, power  402 , cooling  404 , physical space  406 , a share of capital expenditure (CAPEX) costs  408 , and a share of operating expenditure (OPEX) costs  410 . The server  214  further may consume the resources of the networks  218 , including, for example, a local area network (LAN)  420  and a storage area network (SAN)  422 . 
     However, the server  214  may provide the container systems  212  with various physical resource services, including, for example, CPU bandwidth  430 , memory  432 , network I/O bandwidth  434 , and storage I/O bandwidth  436 . The container systems  212  may also consume storage resources  438  from the storage element  216 , and, in turn, may offer services (such as services  440  and  442 ) to the application  210 . The application  210 , on the other hand, may offer services to respective business activities of one or more business units  450 . 
     According to various embodiments, the allocation of resources and the processing of workloads through the supply chain, as described above, may be performed through the use of virtual currency. In these cases, supply chain elements use virtual currency to pay for the services they consume and to price the services they offer. For example, a selected application  210  may receive a budget from its business users reflecting the business value of the services that it offers. The application  210  may shop for a container system  212  that offers the lowest priced processing services that the application  210  requires, and may use its virtual budget to pay for these services. The container system  212 , in turn, may use its income of virtual currency to pay for the services offered by the server  214 , the network  218 , and the storage system  216 . Each of the container systems elements  210 ,  212 ,  214 ,  216 ,  218 , and  220  of the ITCS  202  may price their services in virtual currency to reflect their costs, and additionally, or alternatively, to balance supply and demand. 
     According to various embodiments, resource pricing may also be based one or both of capacity or performance characteristics. For example, the server  214  may offer multiple types of processors or CPUs, each with respective clock rates and other characteristics, at different prices. Similarly, for example, storage I/O resources in the storage system  216  and network I/O resources in the network  218  may be priced according to their bandwidth and latency characteristics. This manner of pricing can take into account that, as noted above, I/O pathways internal to a server (i.e., interconnections of containers co-located with a single server, e.g., the containers  120  and  122  as shown in  FIG. 1 ) typically offer higher bandwidth and lower latency than I/O pathways between containers located at different and distinct servers (e.g., the containers  120  and  124  as shown in  FIG. 1 ). Thus, for example, one or more of the components and resources associated with internal I/O pathways (or the aggregate of such components and resources) may be priced lower than components and resources (alone or in the aggregate) for pathways traversing switches and/or involving multiple servers. Alternatively, for example, components and resources associated with such internal I/O pathways may be priced higher to account for an expected increase in performance and thus value to the acquiring entity. 
     The supply chain model of the ITCS  202  is primarily maintained by the supply chain model databases  246  shown in  FIG. 2 . According to various embodiments, the supply chain model databases  246  may include one or more financial databases to debit and credit the respective accounts of customers and providers to reflect the transfer of virtual payments, as discussed in greater detail below. It will be understood, however, that non-monetary transactions may be entered into between a consumer and a provider. 
     The supply chain model databases  246  may be object-relationship databases, such that elements of the supply chain are modeled as objects corresponding to services to be offered. As used herein, the term “objects” refers to data structures including data fields and methods. Examples of service objects include simple and composite service objects. 
     According to various embodiments, simple service objects—or objects relating to the provision of a single type of service—may include the following types of attributes: 
     &lt;service-identifier, units, used, available, duration, price( )&gt;. 
     The “service-identifier” attribute may itself include the following types of attributes as descriptors of the service that may be used for a particular class of services: &lt;name, type, description, element manager&gt;. For example, a CPU service provided by a Dell® server with an Intel iQ9550® processor managed by an element manager ServerEM015 may be assigned the following identifier: &lt;Dell4, CPU, iQ9550, ServerEM015&gt;. 
     The “units” attribute may measure the quantity of service, such as 5 Mhz (CPU), 2 GB (memory) or 10 Mbps (net I/O). 
     The “used” attribute may refer to the amount of the service or resource capacity that is already committed. 
     The “available” attribute may refer to the amount that remains to meet new demands. 
     The “duration” attribute may indicated the period of time over which service is to be rendered. 
     The “price(demand)” attribute may refer to a method whose input is the demand by a service consumer, for a number of service units it requires, which computes the price in virtual currency units, as set by the service provider. For example, the simple service object &lt;&lt;Dell4, CPU, iQ9550, ServerEM015&gt;, 0.1 Ghz, 0.8 Ghz, 2 Ghz, 1 hr, price(x)&gt;, where price(x)=1/(2−0.1x) 2 , may be used to describe a CPU service named Dell4, providing an Intel processor of type Q9550 for one hour in units of 0.1 Ghz. In this case, a request for 0.5 Ghz (5 units) of this CPU service will be priced at price(5)=1/2.25=$0.44 per one hour of use. 
     According to various embodiments, the pricing functions used by simple service objects can be flexibly adapted by element managers to reflect different pricing goals and mechanisms. For example, a server may be shared by 10-100 containers, which preferably utilize no more than 50% of its capacity to avoid congestion. In this case, the percentage of average demand to capacity of a given server resource preferably falls between 0.5%-5%. 
     Consider a commodity service, defined as one where this ratio is very small. With supply far exceeding demand, prices will drop to reflect costs. Thus, a commodity service may be priced at fixed cost-based price. For example, suppose the percentage of average demand to capacity for CPU usage by a container is 0.2%. In such a scenario, the shifting of a container among servers would have negligible impact on the quality of CPU services seen by the containers. CPUs can therefore be priced at a fixed level to merely reflect the costs of providing CPUs. In general, a commodity service may be priced at a fixed level, independently of demand. However, when the ratio of average demand to capacity is sufficiently large, arriving demands may easily deplete the supply absent pricing control, thus requiring higher prices to balance the supply and demand. 
     A sample pricing function that provides such pricing control is:
 
price[ x ]=cost/(1−( U+x )/ C ) 4  
 
     where 
     C=capacity of the resource; 
     U=amount of resource used; and 
     x=new demand. 
     Such a pricing function is proportional to costs, penalizing high utilization. When the utilization u=(U+x)/C approaches its limit of one, prices increase rapidly, preventing all but the highest budget applications from accessing the resource. For example, suppose containers require, on average, 2% of the CPU capacity of servers, but 20% of their storage I/O capacity. In this scenario, a container wanting to deploy with a server supporting three containers will see the following CPU and storage I/O prices:
 
price CPU [0.02 C ]=cost CPU /(1−0.08 C/C ) 4 =cost CPU /0.92 4 =1.4*cost CPU  
 
price I/O [0.2 C ]=cost I/O /(1−0.8 C/C ) 4 =cost I/O /0.2 4 =625*cost I/O .
 
     Thus, in the above-described scenario, CPU is priced at a relatively small multiplier of the cost base of CPU, while the storage I/O is priced at a relatively large multiplier of the cost base of I/O. Although specific pricing considerations and mechanisms have been described, a large variety of pricing functions may be used according to other embodiments to best reflect specific use considerations. 
     Composite service objects, which are objects that include more than one service object and which relate to the provision of multiple types of services, may take the following form according to various embodiments: 
     &lt;service-identifier, service-1, service-2 . . . , service-n&gt;, 
     where service-k is either a simple or composite service object and is referred to as a component of the composite service. In some embodiments, the “duration” attributes of all components of a composite service are identical, and their common value is called the duration of the composite service. For example, a hardware server may be described by the following composite service object: 
     &lt;&lt;server-1, Server, LS41&gt;, CPU4, Memory-2, NIC-3, NIC-4, HBA-2&gt; 
     where Memory-2, NIC-3, NIC-4 and HBA-2 indicate respective simple service objects associated with respective memory services, LAN-interface services provided by two NICs, and SAN I/O services provided by HBA-2. The HBA-2 may itself be described by a simple service object as follows: 
     &lt;&lt;HBA-2, FC-HBA, Emulex, LP11000-M4&gt;, 0.1 Gbps, 1.1 Gbps, 2.9 Gbps, 1 hr, price(x)&gt;. 
     This service object indicates that the duration of the composite service is one hour, as the durations of all components of a composite service are identical. 
     In some embodiments, the price of a composite service is defined as the sum of the prices of all its components. For example, the price of a server object is the sum of the prices of the units of CPU, memory, network I/O and storage I/O required by a consumer. 
     The supply chain model databases  246  are maintained by element managers (such as element managers  234 ,  236 ,  238 ,  240 ,  242 , and  244  shown in  FIG. 2 ), which handle the service objects corresponding to the respective elements that they manage. As explained above with respect to the sample process  300  shown in  FIG. 3 , according to various embodiments, an element manager is initialized by the platform manager  250 , and subsequently the element manager proceeds to populate the supply chain model databases  246  with respective service objects it is responsible for. Once the supply chain model databases  246  have been updated, the element manager continues to update the dynamic attributes of its respective service objects (such as the “used” and “available” attributes). For example, a server manager  238  that is responsible for managing HBA resources will initialize the supply chain model databases  246  with corresponding simple service objects relating to the HBA. The server manager  238  will then monitor and update the “used” and “available” attributes of this simple service object by periodically accessing the HBA instrumentation. 
     As mentioned above, the supply chain economy matches consumers and providers of resources or services by using pricing and budgeting. According to various embodiments, demand for services is matched to supply through a shopping model. A consumer element manager (such as one of element managers  234 ,  236 ,  238 ,  240 ,  242 , and  244  shown in  FIG. 2 ), desiring services from a provider element manager, queries the supply chain model databases  246  in search of the best priced provider or providers of the desired services. The query specifies requirements and the service or services the element manager is requesting. For example, a query may take the following form: 
     Query: Server, CPU.units=50 Mhz, Memory.units=4 GB, StorageIO.units=200 Mbps, NetworkIO.units=100 Mbps. 
     Such a query may retrieve records of composite service objects of the servers  214  offering the respective CPU, memory, storage I/O and network I/O capacity at the lowest price. Once the consumer element manager acquires these records of lowest-priced service objects, it can proceed to extract the identities of the element managers posting these service offerings. The consumer element manager may then pursue direct interactions and contract with one or more respective provider element managers to acquire and pay for the desired services. There exists the possibility that multiple consumers may query the supply chain model databases  246  simultaneously for similar services, and thus potentially interfere with each other&#39;s shopping processes. Such interference may be avoided, for example, by providing standard locking mechanisms to maintain atomicity of the query and purchase transactions. 
     Moreover, various embodiments may use an auction, or bidding model, rather than a shopping model, to match demand and supply. For example, consumer element managers may post respective bids for services in a bidding database, which a provider element manager may then query for the highest bid price offered for its services and contract to serve it. The shopping model is generally preferred to bidding in situations where consumers&#39; demands arrive asynchronously and unpredictably. In such cases, an arriving consumer can find the low-cost provider by searching the supply chain model databases  246 . In contrast, a bidding process requires providers to poll, whether constantly or at intervals, the bidding database to detect arrivals of new bids, while bidding consumers may be required to wait until enough providers have polled the bidding database and accepted the bids, and thus contract with providers based at least in part on chance. There are various situations where bidding may offer benefits over shopping, and those situations may be handled using the principles described herein. 
       FIG. 5  is a flow diagram of an example process  500  for deploying a new consumer element (such as a container) with a provider element (such as a server) in a container system that is used according to various embodiments for balancing the demand and supply of services. According to various embodiments, the dynamic load balancing approach illustrated by example process  500  provides an effective solution to several of the resource management problems described above. For example, process  500  may be used to improve the balancing of demands by containers and the supply of server resources; it may also be used to balance the resource bundle allocated to a container, e.g., to match the amount of CPU, memory and storage I/O bandwidth allocated to the container, in order to improve the use of its virtual budget to best service its resource demands. 
     As shown in  FIG. 5 , once the relevant consumer element managers and provider element managers are running, having been initiated by the platform manager  250 , a consumer element manager shops for lowest cost provider for a bundle of services by querying the supply chain model databases  246  as described above (step  502 ), and contacts the provider element manager to buy services (step  504 ). In the case of a container consumer, for example, the bundle of services to be purchased may include CPU, memory, and storage I/O. 
     The provider element manager determines whether the consumer budget is sufficient to pay the price for the requested provider services (decision block  506 ). If it is determined that there is sufficient budget, the provider element manager deploys the consumer at the provider, which proceeds to process its workload (step  508 ). For example, CPU and memory resources that have been purchased may be allocated to a container by the underlying scheduler of the container system, which may include the use of a traditional operating systems scheduling algorithm. The server element manager configures the scheduler parameters to accomplish fairly accurate allocation of the CPU and memory. Memory may be allocated by specifying an amount of memory to be provided. The container system can allocate physical memory, based on these specifications, or support virtual memory mechanisms that permit over 100% utilization of physical memory. Additionally, the CPU may be allocated by configuring reservations and shares parameters of the scheduler. For example, reservations may be used to allocate a reserved CPU slice, using a time-shared round-robin scheduler, while shares allocate the remaining CPU bandwidth through a Weighted Fair Queuing scheduler. CPU reservations and shares may be viewed as separate services, and may be individually priced according to supply and demand. For example, a low-priority application may be unable to buy reservations, and may thus need to settle for shares, which may be priced lower. A high-priority, mission-critical application, on the other hand, may have sufficient budget to afford sufficient reservations to support its needs. 
     Otherwise, if it is determined that there is not sufficient budget, the consumer element manager initiates a credit check process to decide whether the consumer can increase its budget or sufficiently lower its service demands, and thus continue to run (decision block  510 ). For example, suppose the consumer is a container whose budget is short of paying the cost of a provider server. In that case, the container may use credit it has accumulated to pay for the service, obtain additional budget from the applications it serves, or reduce its demand for services and the corresponding price to the point where it can afford to pay. If one or more of these scenarios is possible, the consumer uses credit, increases its budget and/or lowers its service demands (step  512 ), and the provider element manager thus deploys the consumer at the provider as described above. Otherwise, if none of these options is available, the consumer is suspended and then will either terminate or re-launch when adequate budget becomes available to it (step  514 ), as described in greater detail below. 
     After the provider element manager deploys the consumer at the provider, the provider element manager or the consumer element manager monitors consumer resource usage and adjusts allocation of resources to optimize or improve the use of the consumer&#39;s budget (step  516 ). For example, the provider element manager may find that the consumer is using only 20% of one service it bought, while using 90% of another service it bought. In that case, the provider element manager may reduce the allocation of the first service and use the corresponding released budget to increase the allocation of the second resource. 
     Upon completion or termination of the consumer service period, the provider element manager notifies the consumer element manager (step  518 ), which may proceed to shop for a new provider offering lowest cost services to meet the consumer&#39;s needs (step  520 ). The consumer element manager determines whether the price of the new provider found is lower than the price of the old provider (where the consumer resides at the time), or according to some embodiments, whether it is lower by a threshold amount (decision block  522 ). Assuming it is, the consumer element manager moves the consumer to the new provider, in which case it may also adjust the budget to reflect the price of moving, if any (step  524 ). Namely, according to various embodiments, a price of moving may be factored into the decision making process for whether the consumer should be moved to the new provider, and such price may be subtracted or deducted from the available budget. Otherwise, if the consumer element manager decides to keep the consumer with the old provider, it does not adjust the budget to reflect the price of moving. In either case, the provider element manager (of the new or old provider) checks to see if the consumer budget is sufficient to pay for the provider as described above. 
     According to various embodiments, the process of shopping for a new provider  520  may depend on specific characteristics of the consumer, the resource, and/or the provider. For example, the containers  120  and  124  shown in  FIG. 1  may need to exchange high-bandwidth latency-sensitive communications through a congested switch in the network  160 . Further to the discussion above, internal I/O pathways (including at either the server  102  or the server  104 ) may offer higher bandwidth and lower latency, and thus result in improved performance. Therefore, according to various embodiments, such internal I/O pathways may be priced lower than I/O pathways involving, for example, multiple servers  102  and  104  and network  160 . 
     As an example, in the step  520  described above and shown in  FIG. 5 , the consumer element manager may determine that it would be more economical or efficient to move a consumer element from the server  102  to the server  104  based on reduced I/O pathway pricing. For example, the consumer element manager may discover that the container  120  should be moved to the server  104  to obtain one or more resources and communicate with one or more other elements located at the server  104 . This can be the case where, for example, it is determined at the step  522  that the overall price of providing container  120  with necessary resources is reduced at least in part because of a lower price of the I/O pathway should container  120  be moved to server  104 . In that case, at step  524 , the container  120  may be moved to server  104  so that the I/O pathway becomes more (or entirely) local to server  104 , thus benefiting from higher expected bandwidth capacity and lower latency. 
     According to various embodiments, at step  524 , the budget of the consumer element (e.g., container  120 ) may also be adjusted (e.g., increased or decreased) based at least in part in such change in pricing. As indicated above, in an alternative embodiment, the pricing of resources (e.g., associated with the I/O pathway) may be increased to account for performance improvement that would result from movement of a consumer element to another server and the resulting localization. 
     According to other embodiments, the process of shopping for a new provider  520  may depend on functional characteristics of the consumer or provider. For example, the server  102  may be used to support development of containerized applications. The server  104 —the provider, for example—may be used for testing the containerized application  130 —the consumer, in this example. The process  500  may be used to select a new provider (the server  104 ), from among a group of servers providing rests of containerized applications, to run tests (consumer) of the containerized application  130 . Similarly, the server  104  may be a production system running containerized applications and the process  500  may be used to dispatch the containerized application  130 , and its container  120 , from the development server  102  to the production server  104 . 
     The order of steps in the example process  500  described above is illustrative only, and can be done in different orders. Moreover, it is contemplated that modifications and extensions of the process  500  will be used according to various embodiments. For example, a consumer may need to contract with two or more providers to be deployed, as in the case of a container that needs to acquire a bundle of resources offered by a server as well as SAN switch bandwidth and storage space at a storage array. In such scenarios, deployment of the consumer can be supported by extending step  502  to shop for multiple providers and then repeating the remaining steps for each of these providers. Additionally, for example, as explained below with respect to  FIG. 6 , the example process  500  shown in  FIG. 5  may be modified or extended to enable the adjustment of resource allocations to obtain desired service level agreements (SLAs). 
     According to various embodiments, the above-described supply chain economic principles may also be used to manage software licenses, such as temporary (time-limited) software licenses. For example, regardless of type (such as authorizations of software use per user, per CPU, per server, or per container), licenses may be modeled as resources to be purchased by an application manager  234 , much like other resources that it may purchase from the container  212 . License element managers (while not shown, may be included as part of the platform layer  230 ) may be used to set the prices of the licenses based on costs and demands In this manner, license management may be greatly simplified and unified with the allocation of other types of resources. For example, an application that is unable to acquire a needed license may suspend its operations and release its resources, as explained below, thus increasing the overall efficiency of the system. Additionally, licenses may be more efficiently used, since in situations where the licenses are highly utilized, they will be allocated to high priority tasks, while lower priority tasks may be suspended until they can afford the licenses. As soon as a license is no longer needed, it may be released and available for other tasks. Additionally, an administrator may consider the ROI of licenses, as with other resources, to plan the expansion, or contraction, of licenses capacity. For example, if a license&#39;s ROI is above a certain threshold, it may be desirable to acquire more licenses to increase the supply to meet demand. 
       FIG. 6  is a flow diagram of an example process  600  for delivering service level agreement targets through resource allocation in a container system, which includes many of the steps of process  500  shown in  FIG. 5  and discussed above. Although not required, for the purpose of simplifying the following description, it is assumed that the target service level agreement relates to an application running on a container. However, the service level of other types of computer elements may be controlled in the following manner according to various embodiments. 
     Following the initial monitoring of resource utilization and optimizing of the container&#39;s budget (step  516 ), it is determined whether the consumer service period has terminated (decision block  602 ), in which case the provider element manager notifies the container element manager (step  518 ) as described above. Otherwise, the container element manager monitors and obtains the value of the SLA parameter of interest, such as the average transaction rate of an application, the average transaction delay of an application, the average communications latency of the application, or the number of transactions performed within a predetermined prior time period by an application (step  604 ). For example, an application element manager may monitor the value of the SLA parameter, through respective instrumentation, and inform the container element manager of the SLA parameter. The application may define its SLA goal as 100 transactions per second, in which case the SLA parameter of interest is transaction-rate. In general, because SLA parameters can be assumed to increase monotonically with the amount of resources allocated to an application, the management of SLAs may be accomplished as described herein by finding a budget and a respective resource allocation that will accomplish the target SLA value. 
     The container element manager determines whether the SLA parameter of interest is below a desired target (decision block  606 ), in which case, for example, the application&#39;s payments to the container (e.g., of virtual currency units) are increased such that the container&#39;s budget is increased, and it is able to purchase more resources to increase the SLA parameter of the application (step  608 ). After such an increase, the container&#39;s budget use is again monitored and optimized or improved as described above. 
     If the container manager determines that the SLA parameter is at or above the desired target, it is determined whether the SLA parameter exceeds the desired target by more than an acceptable threshold (decision block  610 ), in which case the payments are reduced, thus reducing the container&#39;s budget and the resources it buys, saving on applications costs, and keeping the SLA performance within a desired tolerance range (step  612 ). After such a reduction, the container&#39;s budget use is again monitored and optimized or improved as described above. If the SLA parameter is within the acceptable range, however, a reduction is not applied, and the process is repeated until it is determined that the consumer service period has been completed or terminated. 
     According to various embodiments, the process  600  for delivering service level agreement targets through resource allocation in a container system may be modified, adapted, and/or simplified for certain resources and SLA metrics. For example, in the case of allocation of I/O pathways to reduce or minimize latency, the process  600  may be modified as follows. The SLA parameter may be selected as the latency-hop-count, e.g., the number of physical switches traversed by an I/O pathway. For example, I/O pathways between elements located, or resident, at the same server (e.g., the containers  120  and  122  in  FIG. 1 ) generally do not traverse any physical switch, and thus may be described as having a latency-hop-count of 0. Such I/O pathways may also be referred to as having Class-0 Latency SLA. On the other hand, I/O pathways between elements located or resident at different servers (e.g., the containers  120  and  124  in  FIG. 1 ) and attached to a common switch (e.g., a common switch of the network  160 ) may be described as having a latency-hop-count of 1, and may be referred to as having Class-1 Latency SLA. According to various embodiments, an I/O pathway may involve two or more physical switches, and may be described as having a latency-hop-count of 2 (or more) and referred to, for example, as having Class-2 Latency SLA. 
     According to various embodiments, the latency-hop-count associated SLA value may be described with respect to the ordinal preference {Class-0, Class-1, Class-2, . . . Class-n}, where Class-0 is preferred to Class-1, Class-1 is preferred to Class-2, and so on to the extent additional Classes are defined. With respect to the process  600 , a comparison can be made between a Target Latency Class and an Actual Latency Class (e.g., Target=Class-0, Actual=Class-1) at step  606 . If the Actual Latency Class does not meet the Target Latency Class, payments to the consumer (e.g., the container) may be increased at step  608 , and, following return to step  516 , an I/O pathway can be acquired that can deliver the Target SLA Value (e.g., Class-0). For example, the process  600  described with respect to  FIG. 6  can be modified in a manner consistent with the above description so as to simplify the monitoring and control of SLA values to classification of the I/O pathway into latency class. 
     It will be understood that the SLA-delivery process  600  described above may be flexibly adapted to achieve various goals, such as improving its handling of stochastic fluctuations of an SLA parameter. For example, the steps of increasing (step  608 ) and decreasing (step  612 ) payments by the application to the container may use standard mechanisms of Stochastic Approximation theory, including the Robbins-Monro or Kiefer-Wolfowitz algorithms, to regulate the changes in payments to assure convergence. Such a design may be implemented, for example, to achieve more desirable results in connection with non-monotonic SLA parameters. For example, an embodiment using a Robbins-Monro procedure may replace steps  606 - 612  with the following iteration:
 
 R ( n+ 1)← R ( n )+ a ( n )[SLATarget−SLAParameter( R ( n ))]
 
     where n is a counter of the iterations, R(n) is a vector describing the resource bundle allocated after n iterations, SLATarget is the desired value of the SLAParameter, and SLAParameter(R(n)) is the observed value of the SLAParameter after n iterations. The vector a(n) represents the increase/decrease of resources through the n-th step of the iteration; typically a(n)=a/n, where a is a fixed bundle. 
     Although the SLA-delivery process  600  described above uses an economic model and virtual currency units to control SLA levels, other manners of controlling SLA levels may be used according to various embodiments. For example, the allocation of resources to a container, or to an application, may be independent of any economic budget or transfer of virtual currency units, and may instead be based on other measures of an application&#39;s or container&#39;s importance. 
     The process  500  described above may also be modified or extended according to various other embodiments. For example, since current container systems are not readily adaptable to handling the management of storage I/O through HBA or storage systems schedulers, as an alternative to an arbitrary first-come-first-serve process, the process  500  described above may be modified or extended as shown in  FIG. 7  to facilitate the handling of storage I/O. 
       FIG. 7  is a flow diagram of an example process  700  for economic-based I/O scheduling in a container system, which includes many of the steps of the process  500  shown in  FIG. 5  and discussed above. Although not required, for the purpose of simplifying the following description, it is assumed that the consumer is a container, the provider is a server, and the resource is storage I/O. It will be understood that, according to alternative embodiments, the resource being managed may be other types of I/O, such as network I/O. 
     Following the deployment of the container at a server (step  508 ), the server element manager monitors storage or network I/O usage by one or more containers, such as by collecting data from one or more of the container system, the HBAs (step  702 ), or the NIC. According to various embodiments, the server element manager may be configured to prevent congestion along storage I/O pathways, as might occur in cases of usage levels approaching the capacity limits. For example, the server element manager may prevent congestion by using pricing functions as described below that increase prices dramatically when utilization approaches 50% of the capacity. 
     The server element manager optimizes or improves the resources allocated to containers, as described above (step  516 ), such that containers acquire a share of the storage I/O resources that is commensurate with and optimally reflects their budget. The server element manager then periodically estimates both the average storage I/O capacity used and the average available I/O capacity, and updates the respective attributes of the storage I/O objects in the above-described supply chain model databases  246  with this usage data (step  704 ). It is noted that the usage data reported to the supply chain model databases  246  will impact price computations, with excessive utilization of storage I/O capacity resulting in respective price increases, and higher prices in turn deflecting demand by new or existing containers to servers with lower utilization (and prices) of storage I/O. For example, price competition over using storage I/O resources may result in migration of low budget containers from overloaded servers to other servers where storage I/O resources are more highly available, and are thus priced lower. Higher priority containers, on the other hand, may use their higher budgets or credit to obtain a preferential share of storage I/O resources. 
     The server element manager also computes the actual (versus projected) costs expended by each container, and applies these prices to handle its current commitments to containers (step  706 ). For example, higher usage of storage I/O results in higher prices and immediate costs assigned to containers, such that containers of lower priority and high storage use requirements may quickly exhaust their budget or credit and be suspended or terminated, as described below. In this manner, the low priority containers relinquish storage I/O capacity to containers having a higher priority and, thus, a higher budget. 
     Based on the computed costs, the server element manager evaluates whether the container&#39;s budget is sufficient to pay the cost (decision block  708 ). If it is, the service period of the container continues until it ends, and the server element manager notifies the container element manager of the completion of the service period (step  518 ). 
     Otherwise, if the container&#39;s budget is not sufficient, the server element manager evaluates whether the container&#39;s credit (costs minus budget) exceeds an acceptable credit threshold (decision block  710 ). According to various embodiments, high priority containers may have higher budgets and credits and can thus afford to overpay the server element manager to guarantee that they do not run out of storage I/O resources. If it is determined that the container&#39;s credit exceeds the threshold, the container element manager initiates a credit check process to decide whether the container can increase its budget or sufficiently lower its service demands, and thus continue to run (decision block  712 ). If possible, the container makes any necessary adjustments (such as a budget increase in the case of high priority containers, or reduced service demands) and continues to run (step  714 ), until the service period has ended and the server element manager has notified the container manager of the termination of the service period as described above. Otherwise, the server element manager suspends or terminates the container execution and notifies the container element manager, which becomes responsible for addressing the suspension or termination (step  716 ). 
     Upon termination of the service period and notification to the container element manager, the server element manager reports usage data to the container element manager and settles any credit, overpayments or underpayments with the container element manager (step  718 ). The container element manager may then proceed to shop for a new server offering lowest cost services to meet the container&#39;s needs (step  520 ), as explained above. 
     The economic-based scheduling process  700  described above may be used effectively to de-correlate peaks of competing, bursty I/O flows. For example, consider the scenario of four containers sharing a common server and a 4 Mbps Fiber Channel HBA, where the containers generate average storage I/O flows of 250 Mbps, 250 Mbps, 200 Mbps and 300 Mbps, respectively. The aggregate demand average of 1 Gbps consumes only 25% of the HBA capacity. A resource scheduler may limit its consideration to only the average demand which, in this case, would be manageable by the HBA and SAN. However, consider an alternate scenario where the I/O traffic streams are bursty, with a peak/average ratio of five for each container. If the four I/O streams associated with the containers are uncorrelated, their peaks will be likely dispersed and the peak of the aggregate stream will generally be less than 2 Gbps, which can be handled by the HBA and SAN with negligible or relatively few queuing delays. However, if the I/O streams are correlated, their peaks may be compounded to generate, for example, up to 5 Gbps peaks, utilizing 125% of the capacity and generating sustainable congestion, delays, and losses. The scheduling process  700  described above reduces the likelihood of compounded peaks, since they result in peak prices and a corresponding depletion of budgets and credits of low budget containers, leading to suspension, termination, or migration of such containers to servers with lower storage I/O prices until they find servers where their peaks are sufficiently de-correlated from other containers. 
     Thus, the allocation of containers to common servers according to the scheduling process  700  may result in substantially de-correlated peaks and substantially reduce the peak/average ratio seen by servers. For example, consider the example of four containers above. If their peaks are uncorrelated, the peaks of the aggregate stream will generally require at most 1.5 Gbps (the peak of the largest component stream), while their average traffic is 1 Gbps. The burstiness ratio (peak/average) of the aggregate stream 1.5/1=1.5 therefore represents only 30% of the burstiness of the individual streams (1.5 divided by 5). The economic-based scheduling process  700  described above substantially reduces interference not only between traffic averages, but it also reduces the interference between correlated traffic peaks. This results in smoother, less bursty, aggregate workloads, which may permit more efficient processing. 
     It will be understood that, according to various embodiments, the process  700  described above to manage storage I/O flows may applied to other forms of I/O, such as network I/O. For example, the above description should be understood to include alternative processes whereby references to “storage” are replaced by references to “network.” It will similarly be understood that storage I/O flows typically utilize network-I/O flows, such as Ethernet (e.g., Fibre Channel over Ethernet (FCoE)), Transmission Control Protocol/Internet Protocol (TCP/IP) (e.g., Network File System (NFS)), and SAN (e.g., Fibre Channel (FC), Internet Small Computer System Interface (iSCSI)), to transfer information such as storage access commands. The scheduling process  700  is therefore independent of the specific underlying network, and of the specific access commands carried by the described flows. Accordingly, the process  700  may be applied to schedule network I/O flows and thereby provide similar or identical benefits to those associated with storage I/O flows, such as smoothing the peaks of bursty traffic and/or supporting priority services. 
     The order of steps described above with respect to scheduling process  700  is illustrative only, and can be done in different orders. Moreover, the aforementioned beneficial effects are true not only for I/O streams, but for workloads sharing other resources as well. 
     The contracting of services between a consumer and a provider, as described in the example processes above, may include the use of a standard request-response protocol (such as SOAP) to submit a purchase order to the provider and transfer a respective payment. In response, the provider may deploy the service requested by the consumer and respond with a service confirmation. 
       FIG. 8A  is an example purchase order data structure  800  issued by a consumer element manager for use in purchasing services from a provider element manager. The first two fields of the data structure  800 , source-ID field  802  and provider-ID field  804 , respectively identify the source consumer and destination provider. The third field, transaction-ID field  806 , identifies the particular purchase order. The fourth field of the data structure  800 , service field  808 , identifies the service and provides parameters to quantify the purchase. The fifth field of the data structure  800 , payment field  810 , provides payment data including payment amount and authentication data to establish the validity of the payment. Finally, the sixth field of the data structure  800 , authentication field  812 , provides data to authenticate the validity of the purchase order transaction. 
       FIG. 8B  is an example service confirmation data structure  850  issued by the provider element manager for use in confirming or rejecting the purchase of services by the consumer element manager. The first three fields of the data structure  850 , source-ID field  852 , provider-ID field  854  and transaction-ID field  856 , correspond to the first three fields of the data structure  800  described above. The fourth field of the data structure  850 , service confirmation field  858 , includes data to confirm the service and enable the source to access it. Alternatively, assuming the provider has rejected the transaction, the service confirmation field  858  would include data with the reason or reasons for rejection, such as insufficient resources or a price change. Finally, the fifth field of the data structure  850 , authentication field  860 , provides data to authenticate the validity of the service confirmation. 
     As described below, various embodiments may also be used to address the problems of container sprawling and energy consumption in container systems using supply chain economics. Regarding sprawling, as explained in greater detail below, these embodiments may be used to suspend or terminate containers that are no longer needed or productive. These embodiments may also be used to terminate containers, or to disallow their re-activation if in a standby state, that are determined to be inconsistent with the current versions of their container system and applications. Regarding energy consumption, these embodiments may be used to consolidate and shift containers into fewer servers, for example, while still providing desired SLA performance, and switching other unused or non-productive servers OFF or into standby mode to reduce energy use. The supply chain software model and processes described above provide mechanisms and metrics to quantify how productive or non-productive a service element is. 
     The following description details an example process  900 , shown in  FIG. 9 , for managing the states of container system elements, which as explained further below, may be used to address sprawling and energy consumption issues. For simplicity, the following description assumes that the system element is a container, although the general principles that follow may be readily adapted for any type of system element. 
     A container is first initialized, for example, through the use of an initialize signal generated by a management station (step  902 ) or an automated action of a container manager. Similarly, for example, an application element may interpret events generated by a launch as an initialize signal. 
     After being initialized, the container attempts to obtain an initial budget to acquire resources for its operations (step  904 ). It is next determined whether the container was successful in obtaining an initial budget (decision block  906 ), in which case the container tries to acquire the resources needed to launch a respective service component (step  908 ). Otherwise, it begins the termination procedure by releasing any resources allocated to it (step  910 ). 
     If the container is successful at acquiring resources (decision block  912 ), it is provisioned, deployed, and remains in an active state (step  914 ) until it receives a signal to switch the service element OFF to an idle or standby state (step  916 ). After the terminate signal has been received, the container begins the termination procedure by releasing resources allocated to it, as described above. 
     On the other hand, if the container is not successful at acquiring resources, the container will wait an amount of time for sufficient resources to become available before attempting to acquire resources again (step  918 ). For example, during this waiting period, the container may use an exponential “backoff” mechanism, whereby the container repeats its attempts to acquire resources, but doubles the waiting period between repetitions with every failure. If it is determined that the container should continue to try to acquire resources (decision block  920 ), it will do so as described above in step  908 . Otherwise, for example, if failures persist beyond some timeout period, the container abandons attempts to launch and begins to terminate. 
     Once resources have been released, it is determined whether the container should remain in a standby state (decision block  922 ), in which case the execution of the container stops, but it remains in a suspended or standby state and retains sufficient state data, for example, by using storage services to retain state data in image form, and for which the container may be required to pay (step  924 ). Otherwise, the container terminates execution and may be deleted (step  926 ). 
     According to various embodiments, the applications being executed by the container are first terminated, and then the container is terminated. Such a graceful termination may be pursued through a recursive termination of the supply chain elements supported by the container. For example, a container element manager may issue a terminate signal to a corresponding operating system manager, which propagates the signal to an application manager, which in turn signals termination to is application. The application may then begin the termination steps as described above with respect to the process  900 , after which a termination complete signal to the application manager, and is forwarded to the operating system manager, which in turn sends a terminate signal and receives a termination complete signal back from the operating system. Finally, the operating system&#39;s termination complete signal may be forwarded to the container manage, which can signal the container to terminate. It will be understood that terminating (or even suspending) a container operations may result in damages if conducted improperly or at an inappropriate time. Thus, according to various embodiments, a notification procedure may be invoked to notify administrators of pending terminations or suspensions, such that termination or suspension may only be completed once administrator permission has been received. 
     For a container in standby state, it is determined whether termination should follow (such as by receipt of a terminate signal) (decision block  928 ), in which case the container terminates execution as described above. Otherwise, for example, if it is determined that the container should re-activate, the container seeks to obtain a budget to acquire resources for its operations as described above, for example, upon receiving an initialize signal. It will be understood that the specific actions described above in connection with process  900  may be modified for non-container system elements, and that the order of steps in process  900  are also illustrative only. 
     According to various embodiments, a process such as process  900  described above may be used to control container sprawling by suspending or terminating non-productive system elements, such as containers. For example, consider the ROI of a container, which measures the relationship between the payments it collects from applications and the prices it pays for underlying server and I/O resources. If the container&#39;s ROI is greater than one, the container is earning more than it expends, and the container may be classified as being productive in creating applications value that exceeds the costs of the infrastructures it uses. However, if the container&#39;s ROI is less than one, this means that the container produces less value than the cost of resources it consumes, and the container may thus be classified as non-productive. In this manner, ROI is one example of a metric of productivity that may be used in determining whether a system element should be suspended or terminated, or whether it should remain active. 
     A process such as process  900  described above may be used to assure, for example, that applications&#39; budgets are sufficient to keep one or more containers&#39; ROI greater than one, and to notify applications&#39; administrators (element managers) as needed when budgets are low. It the ROI of one or more containers remains less than one for more than a threshold period, for example, it may indicate that an application&#39;s budget is too low to sustain productive operation, and that the corresponding, non-productive container should be suspended or terminated. For example, a container may receive a terminate signal to switch it OFF to an idle or standby state (per step  916  of process  900  described above) as soon as the container&#39;s productivity level or score (for example, measured by its ROI) has been determined to be less than one for a predetermined time period. Additionally, for example, the length of time that the container&#39;s ROI has been less than one may be a factor in deciding whether the container should be terminated, or only suspended for the time being. 
     Similarly to dealing with the sprawling issue, the process  900  described above and similar processes may also be used for energy management. For example, such processes may be used to suspend or terminate (switch OFF) servers that are classified as being non-productive, as in the case where a server&#39;s ROI is less than one for a sufficiently long period of time. In this case, the server element manager, much like the case of the container manager described above, can monitor the ROI and detect termination or suspension conditions. The server manager may then pursue a termination process, similar to the recursive termination process described above, where all containers on the server are first terminated, or moved to another server, before the server manager suspends the server into Standby state (so as to consume less energy and cooling resources, for example) or switches the server OFF. 
     According to various embodiments, process  900  and similar processes may also be used to assure consistency of a suspended container with changes in applications. For example, the container manager may prevent such inconsistencies by sending a terminate signal, as described above, to all containers whenever their respective operating system or applications software has changed, thus causing the applicable containers to transition from standby to terminate state, at which point it may be deleted. 
     Although the above descriptions consider a single-domain container environment, it will be understood that the principles described herein may also be applied to multi-domain environments, e.g., a multi-cloud environment. For example,  FIG. 10  is a block diagram of an example multi-domain software system environment  1000  for managing virtualized resources in “multi-cloud” systems. According to various embodiments, as shown in  FIG. 10 , container environment  1000  includes two example software systems  1002  and  1004 , each of which is similar to the more detailed example software system  200  shown in  FIG. 2 , and which operate in a first and second domain, respectively. 
     As shown, the software system  1002  operating in the first domain includes a user interface subsystem  1006  and one or more functional managers  1008  and  1010 . Together, these elements make up a functional management layer  1012  of software system  1002 , and provide specific management applications as described above in connection with  FIG. 2 . 
     Software system  1002  also includes one or more element managers  1014  and  1016 , which monitor and control one or more respective container stack elements  1018  and  1020 . The software system  1002  also includes one or more databases  1022  (such as the supply chain databases  246  and operations databases  248  described with reference to  FIG. 2 ), as well as a platform manager  1024 . These elements are included in a platform layer  1026  of the software system  1002  to provide the infrastructures for monitoring the container stack elements  1018  and  1020 , modeling these container stack elements as part of a supply chain economy, and controlling the operations of the container stack elements, as described above. 
     The software system  1004  operates in the second domain, includes similar elements as the software system  1002 , and also includes a proxy manager  1030 . According to various embodiments, the domain software system  1004  exports one or more resources or services to the domain software system  1002  by using the proxy manager  1030 . The proxy manager  1030  exports instrumentation to monitor and control these provided resources to one or more of the element managers  1014  and  1016 , such as container element managers, of the first domain software system  1002 . The first domain software system  1002  may view the second domain software system  1004  as a service element integral with its supply chain model. 
     According to various embodiments, the second domain software system  1004  is in complete control of the resources (or services) and capabilities exported to the first domain software system  1002 . For example, the software system  1004  may be an external cloud provider exporting raw server services to the software system  1002 . In this case, the software system  1002  can access these services, using its local element managers  1014  and  1016 , to allocate, for example, CPU, memory, and storage resources at the second domain software system  1004  and then monitor and control their use and operations. 
     Moreover, according to various embodiments, software systems  1002  and  1004  are separately owned and/or managed. For example, software system  1002  may be owned and operated by a small business that experiences steady computing needs except for two hours in each day, during which time its computing needs are consistently elevated. In this case, rather than purchasing permanent computing resources to handle the two hours of elevated needs per day, for example, software system  1002  may lease or purchase additional computing resources from software system  1004  (e.g., owned by Amazon.com, Inc.) on an as-needed basis and transfer excess workloads to software system  1004  (“bursting”). For example, computing resources from software system  1004  may be leased or purchased to facilitate the execution of a multi-tier web service by a cluster of containers (or applications). In that example, the software system  1002  may lease or sell resources from software system  1004  to execute this cluster of containers (or applications) and then migrate the container cluster (or application cluster). For example, the migration may take place from a private cloud of a small business to the public cloud of another business (e.g., of Amazon, Inc.). It is noted that, according to various embodiments, even if needed computing resources are available from within software system  1002 , such resources may be purchased from software system  1004  based on relative price offerings. 
     The asymmetric relationship between software systems  1002  and  1004  shown in  FIG. 10  and described above may be extended to provide full symmetry. In that case, the first domain software system  1002  would incorporate its own proxy manager (not shown) to export services to the second domain software system  1004 , which would integrate it within its supply chain through one or more of its respective element managers. 
     The supply-chain principles discussed herein may be used to scale containers up/down, by adding or removing resources to existing container components, or to scale containers out, by adding more container components or suspending containers. The decisions to scale up/down and out are based on a supply chain  1100  outlined in  FIG. 11 , and the revenues and expenses of each of the entities involved in that Figure. The supply chain  1100  may also be used to determine the sizing and placement of containers, when a selected container is deployed, and to determine future sizing and placement requirements based on anticipated changes in container load. 
     Turning to  FIG. 11 , according to various embodiments, the supply chain  1100  may include two types of entities, namely, Service Entities (SEs), such as a Virtual Machine  1110  or a Container  1120 , and Resources, such as CPU Allocation (CPUAllocation)  1102  and Memory Allocation (MemAllocation)  1101 . 
     In some embodiments, the market may suggest an increase of (scaling up) the Memory Allocation  1101  of the Container  1120 , or it may suggest the creation of another instance (scaling out) of the Container  1120 . According to various embodiments, decisions to scale up/down will apply to Resources only, while decisions to scale out will apply to SEs only. 
     For example, in  FIG. 11 , the MemAllocation  1101  of the Container  1120  may reduce as a result of congestion for resources at the Virtual Machine level. Increased utilization of MemAllocation  1101  of the Virtual Machine  1110  will lead to increased MemAllocation price. In turn, the increased MemAllocation price increases expenses of MemAllocation for the Container  1120 , leading to a decision to reduce the size of MemAllocation of the Container  1120 . 
     With reference now to a supply chain  1200  shown in  FIG. 12 , the Container  1120  consumes directly from a Physical Machine  1210 . The MemAllocation size may also reduce as a result of congestion for resources at the Physical Machine level. Increased utilization of Physical Machine MemAllocation will lead to increased MemAllocation price, which in turn increases expenses for MemAllocation on the Container  1120 , leading to a decision to reduce the size of MemAllocation of the Container  1120 . 
     Container MemAllocation size may increase as a result of over provisioned resources at the Virtual Machine level. Decreased utilization of Virtual Machine CPUAllocation due to a high capacity will lead to decreased CPUAllocation price, which in turn decreases expenses for CPUAllocation on the Container  1120 . If the Container  1120  has high revenues for CPUAllocation this would lead to a decision to increase the capacity of CPUAllocation on the Container  1120 . 
     Decisions for both resources and SEs are based on revenues and expenses of these resources. Similarly, expenses and revenues can be set to a predetermined value as desired. For example, the price of MemAllocation can be set to a minimum value to force higher expenses if attempting to maintain the size of the MemAllocation of the Container at or below some value. This advantageously avoids unnecessary resizing only for the purpose of having additional MemAllocation. Accordingly to other embodiments, the price of MemAllocation can be set to a maximum value. 
       FIG. 13  shows an example process  1300 , which illustrates how a decision is made to scale a resource allocation up or down. Turning to  FIG. 13 , the process  1300  first determines if the revenue/expense of a commodity is greater than a predetermined value X (decision block  1301 ). If so, then the capacity of the resource is scaled up until the revenues are equal to the expenses (step  1302 ). If the revenue/expense of the resource is less than a predetermined value Y (decision block  1303 ), then the resource allocation is scaled down until the revenues are equal to the expenses (step  1305 ). Otherwise, if the revenues/expense of the resource is within the range defined by the values X and Y (decision blocks  1301  and  1303 ), then the resource allocation is not scaled (step  1304 ). 
     Advantageously, the values of X and Y provide a mechanism to tune the responsiveness of the system to increases or decreases in demand. The value of revenues/expenses captures the profitability of the resource allocation (or the SE). If the ratio is &gt;1, the resource is profitable. If it is &lt;1, it is losing money. In process  1300 , X is typically (but not necessarily) &gt;=1 and Y is typically (but not necessarily) &lt;1. Stated in another way, an increase in capacity typically is suggested when the resource is profitable, and a decrease when it is operating at a loss. 
     As an additional advantage, decisions capture the entire state of the system, and can optimize the system as a whole. Increased utilization of a resource will lead to increased price for the resource, which in turn increases expenses for the resource. In some embodiments, the ideal price for scaling the resources provides 70% utilization. 
     In some embodiments, revenues and expenses can refer to the accumulated revenues and expenses over a period of time. Different periods of time can be used to adjust the decision-making behavior (e.g., aggressive versus conservative behavior). Short time frames lead to aggressive decisions, where the system responds very quickly to changes in the supply and demand anywhere along the supply chain. This can be used, for example, to respond quickly to congestion for resources and guarantee the quality of service offered to the entities in the system. Long time frames dampen the effects of short-term changes in the supply and demand, and reflect accurately the longer-term trends of the demand and supply. 
     A similar decision tree to the one shown in  FIG. 13  is depicted in  FIG. 14 , which illustrates an exemplary process  1400  for scaling SEs. Instead of resizing resources as shown in  FIG. 13 , the process  1400  concerns creating a new instance of a SE, or suspending the operation of an existing SE, depending on the expenses and revenues of the SE. Turning to  FIG. 14 , the process  1400  first determines whether the revenue/expense of a SE is greater than a predetermined value X (decision block  1401 ). If so, then a new instance of the SE is created (step  1402 ). If the revenue/expense of the SE is less than a predetermined value Y (decision block  1403 ), then the operation of the SE is suspended (step  1405 ). Otherwise, if the revenues/expense of the SE is within the range defined by the values X and Y (decision blocks  1401  and  1403 ), then the SE is unchanged (step  1404 ). 
     As discussed above, in addition to managing container resources, the supply-chain principles discussed herein also may be used to manage application performance in other virtualization systems. For example, an application server requires a certain amount of memory and CPU resources. A database will also require a certain amount of storage. In order for the application to perform adequately, the application must be allocated a sufficient amount of resource. In order for the infrastructure to be utilized efficiently, the application should only consume what it requires at any given point in time. 
     Accordingly, with respect to application performance, the supply-chain principles discussed in  FIGS. 13 and 14  can be used to scale up/down, by adding or removing resources allocated to the application, or to scale out, by adding more application components, or suspend application components. Some examples of application resources include, without limitation, java heap, thread pools, and connection pools in an application server or data space and log space in a relational database. These decisions are based on a supply chain  1500  outlined in  FIG. 15 , and the revenues and expenses of each of the entities involved in that Figure. 
     Turning to  FIG. 15 , the supply chain  1500  includes the two types of entities discussed with reference to  FIG. 11 . Specifically, the supply chain  1500  illustrates the SEs, such as the Physical Machine  1210 , the Virtual Machine  1120 , or an Application Server  1530 , and the Resources, such as Memory (Mem)  1501 , Virtual Memory (VMem)  1502 , and Heap  1503 . 
     As discussed above, the resources and SEs have expenses and revenues. For example, the revenues of a virtual central processing unit (VCPU)  1504  sold by the Virtual Machine  1120  are generated from the Application Server  1530  buying this resource. Expenses of the VCPU  1504  come from paying to acquire a necessary resource, such as CPU  1505 , from the underlying Physical Machine  1210  hosting the Virtual Machine  1120 . 
     Similarly, a SE has revenues which can be the sum of the revenues of the resources it sells, while its expenses can be the sum of the expenses of the resources it buys. As another example, the revenues of the Virtual Machine  1120  can be the sum of the revenues of the VCPU  1504  and the VMem  1502  that it sells to the Application Server  1530  in  FIG. 15 , while its expenses are the sum of the expenses to acquire the CPU  1505  and Mem  1501  from the Physical Machine  1210 . 
     Revenues and expenses can depend on the prices of resources, which in turn can be a function of supply, e.g., attributes of the resource such as its capacity, as well as the demand—how much of the capacity is currently utilized by resources or SEs consuming this resource. In one embodiment, price is a function of the utilization (U) of the resource, and depends on it through the formula: 
     
       
         
           
             1 
             
               
                 ( 
                 
                   1 
                   - 
                   U 
                 
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               2 
             
           
         
       
     
     For example, an application server requires java heap in order to process transactions. This java heap is allocated from the underlying virtual machine&#39;s virtual memory allocation. In the event that the demand for java heap is very high (e.g., generating revenue for the application server), and the price of virtual memory from the virtual server (e.g., determined by the combination of supply and demand) is sufficiently low, then the application server will be able to buy more virtual memory from the virtual server and allocate additional java heap. In the event that the demand for java heap is low and the price of virtual memory is high then the application server will decrease its allocation of java heap and return virtual memory to the virtual machine to be used by other applications. 
     In some embodiments, the buyer can be assigned a budget for purchasing the resources. 
     Decisions for both resources and SEs are based on the revenues and expenses of these resources. Similarly, expenses and revenues can be set to a predetermined value as desired. For example, the price of VMem can be set to a minimum value to force higher expenses if attempting to maintain the size of the Heap at or below some value. This advantageously avoids unnecessary resizing only for the purpose of having additional VMem. Accordingly to other embodiments, the price of VMem can be set to a maximum value. 
     In some embodiments, the market may suggest to increase (scale up) the Heap size of an Application Server, or it may suggest to create another instance (scale out) of the Application Server. These decisions can be based on the process  1300  for resizing resources and process  1400  for scaling SEs as discussed above. 
     As discussed above, revenues and expenses can refer to the accumulated revenues and expenses over a period of time and different periods of time can be used to adjust the decision-making behavior (e.g., aggressive versus conservative behavior). For example, longer periods of time can be used to anticipate future needs for extra application servers based on steadily increasing revenues that reflect an increase in demand. Conversely, a longer term decrease in revenues indicates that the steady state operation of a system may not require a particular SE. 
     The use of supply chain economic principles and other principles explained above serve several purposes and provide several potential benefits, both expressly numerated and otherwise. For example, these principles can be used to provide a common software framework and abstractions to unify and automate the management of container systems. More specifically, they can be used to optimize or improve the allocation of IT resources (such as I/O resources or software licenses) to best process applications workloads according to their business value. The principles of supply chain economics can also be used to balance workloads to minimize disruptive operating conditions, such as I/O congestion, and to reduce resource waste by terminating or switching-off underutilized resources. These principles can also be used to empower business units to monitor and control the delivery of SLAs to their applications, as well as the ROI of individual elements and the overall container system. In addition, for example, these principles can be used to handle the management of virtual resources in a multi-cloud (or multi-domain) system. 
     Additionally and/or alternatively, the management of resources in container systems and conventional virtualization systems can include not only supply-chain based methods, but also access regulation to the resources.  FIG. 16  illustrates an exemplary system  1600  for regulating access of consumers  1610  (e.g., electronic applications) to resources and services (e.g., storage). In one embodiment, this regulation occurs through the use of access permits (not shown) that the consumer  1610  acquires from an intermediate entity—an Action Manager (AM)  1620 —prior to accessing the resource or service. As shown in  FIG. 16 , the AM  1620  regulates access to a provider  1630  of the resource or service. For example, regulating access includes controlling the number of concurrent accesses, and/or the rate at which consumers  1610  access the resource, as desired. 
     In some embodiments, there is one type of permit per provider  1630 . According to various embodiments, the AM  1620  can sell multiple types of action permits, regulating access to a number of resources. Each permit can be associated with a predetermined price. Additionally and alternatively, this price can be dynamically adjusted taking into consideration the availability of permits possessed by the AM  1620 . 
     Permits sold by the AM  1620  can create both revenues and expenses for the AM  1620 . The revenues come from the price the consumer  1610  has to pay to the AM  1620  to buy the permit. The expenses come from the price the AM  1620  has to pay to the resource provider  1630  for the right to sell these permits. For example, the AM  1620  may need to pay for Input/output Operations Per Second (IOPS) offered by a storage controller in order to allow access to the consumer  1610 . 
     In some embodiments, the price that the AM  1620  pays for the right to sell these permits is determined by the provider  1630  based on one or more of the following parameters: the capacity and the percentage the provider  1630  wishes to make available to the consumers  1610 ; the current load of the provider  1630 ; and the rate at which the provider  1630  wishes its resources to be accessed. 
     The AM  1620  dynamically can adjust the number of permits it possesses at any time, depending on its revenues and its expenses. For example, if the AM  1620  is profitable (e.g., the charges based on price it is selling the permits to the consumer  1610  is higher than the charges based on price it pays to the provider  1630  for the right to sell these permits), the AM  1620  can consider increasing the number of permits it sells. Alternatively, if the AM  1620  is losing money, the AM  1620  can consider decreasing the number of permits it is selling. 
     Advantageously, the AM  1620  can be used to avoid I/O congestion in storage controllers when several VMs request to execute heavy-storage applications (e.g., VM Reboots, Antivirus database updates, OS Updates, and so on) at the same time. In one embodiment, the AM  1620  limits the number of concurrent consumers that can access the provider  1630 . It may limit access across types of applications or within each type of application. For example, permits can be priced and provided for all anti-virus, OS updates, etc. separately, or all of them may be constrained by the same permits. In this example, the provider  1630  is the storage controller, while the consumer  1610  is the application performing the heavy-storage task. For instance, the application can be performing an anti-virus update on the virtual machine. 
     Turning to  FIG. 17 , the consumer  1610  (e.g., an application) sends the AM  1620  a request  1601  to acquire the appropriate number of permits (e.g., 5) for the provider  1630  (e.g., a storage controller) of the storage associated with the VM. It will be understood that, although reference is made to a storage controller with respect to  FIG. 17 , according to various embodiments, other types of providers and resources are managed using similar principles and permits. After a request  1601  has been received, the AM  1620  subsequently determines  1602  if the request includes a sufficient budget, and if the AM  1620  has enough permits to satisfy the request  1601 . If so, the AM  1620  replies to the consumer  1610  with the appropriate permits and charges. After buying the permits, the consumer  1610  accesses  1602  the storage through the provider  1630  and performs the update. After completing the update, the consumer  1610  releases  1604  the permits such that the AM  1620  can re-sell them. The AM pays  1605  the provider  1630  for the use of the permits it is selling. According to various embodiments, payment for the use of permits can occur before, after, or simultaneously with storage access. 
     In an alternative embodiment, the number of concurrent accesses to a resource may vary. For example, the AM  1620  adjusts the number of permits it is selling, to reflect the ability of the provider  1630  to satisfy concurrent requests by consumers  1610 . For example, when the AM  1620  pays the provider  1630  for the use of the permit, the AM  1620  adjusts the number of the permits it sells based on how profitable it is. If demand for permits for a specific provider  1630  is high, the AM  1620  raises the prices for this permit, advantageously increasing revenues. 
     To become even more profitable, the AM  1620  can request the right to sell more permits from the provider  1630 . If the provider  1630  agrees, the provider  1630  raises the price the AM  1620  has to pay for these rights. As the demand increases, the provider  1630  continues to increase the price it charges the AM  1620 . At a threshold price, the AM  1620  can no longer make a profit, and the AM  1620  does not request any further increase in the number of rights it can sell. Similarly, the number of permits sold by the AM  1620  can decrease as a result of reduced demand by consumers  1610 , or increased prices by the provider  1630 . 
     In yet another embodiment, the AM  1620  controls rate of concurrent accesses to a particular resource. For example, the AM  1620  limits the rate at which the applications are accessing the storage controller to perform the heavy-storage tasks. In this case, once the application releases the permit, and until the predetermined period of time has elapsed, the AM  1620  cannot resell this permit. The storage controller can charge the AM  1620  a very small amount for the right to sell a first predetermined number of permits within a period of time, and then increase the price to infinity for permits beyond the first predetermined number in this period. 
     In yet another embodiment, the consumer request to access one or more permits is made directly to the resource or service provider. 
     In yet another embodiment, the AM  1620  controls the total number and/or the rate at which a group of consumers accesses a group of resources. 
     Another aspect discussed above formulates and evaluates the option to move the consumer to a new provider. “Formulating” includes the attributes taken into account when considering the option to move to the new provider. The cost of moving can be part of the comparison between two different alternatives (e.g., keeping a VM in an existing infrastructure or moving the VM to an external cloud provider). Cost can be expressed in actual currency or any unit suitable for the comparison. For example, moving time can be expressed in a real value that quantifies the cost of the VM downtime. In contrast, if there is a strict limit on acceptable downtime, the cost of moving the VM can be expressed in terms of time. 
     “Evaluating” includes making the decision (e.g., initiating an action based on the decision) and determining the right time to take the action. Compared to other economics-based decision-making systems, one embodiment described herein postpones the decision for the future, advantageously waiting for a sufficient amount of time until the decision-maker is convinced that the decision is the right one. 
     For example, a virtualization system is considering taking an action A with the cost of taking this action represented as C(A). If the action is taken, the savings over time is S(t). The decision to take the action at the time to when the savings would have exceeded the cost of the action is represented by the following Equation:
 
 S ( tA )&gt;= C ( A )
 
     In one embodiment, with reference to  FIG. 18 , a virtualization system  1800  controls moves of VMs  1810  between different storage (or resource) providers  1820  to avoid frequent moves of VMs  1810  between different storage providers  1820  in a datacenter (DC)  1830  or across different datacenters. 
     For example, the VM  1810  is evaluating a move to one or more service providers  1820 , such as storage providers SP 1 , SP 2 , . . . SP N . Although storage providers  1820  are used herein as an example, it will be understood that the concepts disclosed herein can be applied to other types of service or resource providers. 
     In some embodiments, the cost C(Ai) of moving to provider i is set to a value that is proportional to the size of the data to be moved from the current SP to SP i , multiplied by a factor P i  that captures the ‘proximity’ of the current SP to SP i . For example, if the current and the future SPs are in the same datacenter  1830 , P i  could be set to 1, whereas if they are in different datacenters  1830 , it could be set to 10, to capture that it is more expensive to move across datacenters  1830  as opposed to moving within the same datacenter  1830 . 
     The consumer periodically checks the prices at the current and each provider i, calculates the saving for this period and adds them to the savings from the previous periods. The price of the new provider for the current period may be higher than that of the current provider, and as a result the savings for this period will be negative and will decrease the total savings from previous rounds. The moment the savings up to now exceed the cost C(A i ) the VM  1810  decides to move SP i . 
     In an alternative embodiment, when the consumer considers moving to a new provider, the current provider gives the consumer some credit (e.g., equal to C(A)) to convince the consumer to stay. The consumer accepts the credit, and periodically checks the price of the new provider. If the price is cheaper, the consumer can use this credit to subsidize any loss of not having moved there. If it is more expensive, the consumer adds her gain to the credit. If the consumer runs out of credit, then the consumer can decide to move. 
     Advantageously, the system accounts for the fact that a decision that looks good now may not be good in the future. For example, a consumer that buys bandwidth from a network provider may see a cheaper price offered right now by a new provider. However, the new provider may change the price an hour later, and this new price may be higher than the price of the current provider an hour later. 
     Additionally, the system accounts for the actual behavior of other users. Assume a VM is interested in the latency of accessing data stored on a disk, and a decision is made to move its data from the current to a new disk that currently has lower latency. For large amounts of data, the move could take hours to complete. While the move takes place, other consumers who also see a slightly reduced latency move to the same new provider—effectively increasing the latency for everyone, and making it a bad decision. 
     Furthermore, the amount of time it takes to determine that the decision may be good is related to the cost of performing the action. Therefore, expensive decisions are carefully validated over longer periods than cheaper decisions, ensuring that undertaking the cost of the action will pay off in the future. 
     Advantageously, the systems and methods above minimize bad decisions and decisions that would frequently alternate between the current and the new provider. 
     Embodiments of the subject matter and the functional operations described in this specification can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. Embodiments of the subject matter described in this specification can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a tangible program carrier for execution by, or to control the operation of, data processing apparatus. The tangible program carrier can be computer readable medium, such as a machine-readable storage device, a machine-readable storage substrate, a memory device, or a combination of one or more of them. 
     The terms “data processing apparatus” “data processor”, or “processing device” encompasses all apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, or multiple processors or computers. The apparatus can include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them. 
     A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, or declarative or procedural languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub programs, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network. 
     The processes and logic flows described in this specification can be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit). 
     Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read only memory or a random access memory or both. The essential elements of a computer are a processor for performing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto optical disks, or optical disks. However, a computer need not have such devices. Moreover, a computer can be embedded in another device, e.g., a mobile telephone, a personal digital assistant (PDA), a mobile audio or video player, a game console, a Global Positioning System (GPS) receiver, to name just a few. 
     Computer readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto optical disks; and CD ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry. 
     To provide for interaction with a user, embodiments of the subject matter described in this specification can be implemented on a computer having a display device, e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, for displaying information to the user and a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input. 
     Embodiments of the subject matter described in this specification can be implemented in a computing system that includes a back end component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a front end component, e.g., a client computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the subject matter described is this specification, or any combination of one or more such back end, middleware, or front end components. The components of the system can be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a LAN and a wide area network (“WAN”), e.g., the Internet. 
     While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any invention or of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments of particular inventions. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination. 
     Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. 
     Particular embodiments of the subject matter described in this specification have been described. Other embodiments are within the scope of the following claims. For example, the actions recited in the claims can be performed in a different order and still achieve desirable results. As one example, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In certain implementations, multitasking and parallel processing may be advantageous.