Showing papers on "Service-level agreement published in 2010"

Conceptual SLA framework for cloud computing

Abstract: Cloud computing has been a hot topic in the research community since 2007. In cloud computing, the online services are conducted to be pay-as-you-use. Service customers need not be in a long term contract with service providers. Service level agreements (SLAs) are agreements signed between a service provider and another party such as a service consumer, broker agent, or monitoring agent. Because cloud computing is a recent technology providing many services for critical business applications, reliable and flexible mechanisms to manage online contracts are very important. This paper presents the main criteria which should be considered at the stage of designing the SLA in cloud computing. Also, we investigate the negotiation strategies between cloud provider and cloud consumer and propose our method to maintain the trust and reliability between each of the parties involved in the negotiation process.

Decision Model for Cloud Computing under SLA Constraints

Abstract: With the recent introduction of Spot Instances in the Amazon Elastic Compute Cloud (EC2), users can bid for resources and thus control the balance of reliability versus monetary costs. A critical challenge is to determine bid prices that minimize monetary costs for a user while meeting Service Level Agreement (SLA) constraints (for example, sufficient resource availability to complete a computation within a desired deadline). We propose a probabilistic model for the optimization of monetary costs, performance, and reliability, given user and application requirements and dynamic conditions. Using real instance price traces and workload models, we evaluate our model and demonstrate how users should bid optimally on Spot Instances to reach different objectives with desired levels of confidence.

QoS-Aware Clouds

Abstract: In this paper we discuss the design and experimental evaluation of a middleware architecture that enables Service Level Agreement (SLA)-driven dynamic configuration, management and optimization of cloud resources and services. This architecture has been designed in order to respond effectively to the Quality of Service (QoS) requirements of the cloud customer applications. Typically, an application can be hosted in an execution platform constructed out of (real and virtual) cloud resources. In this context, the application QoS requirements can be specified in a SLA that binds the application to its hosting platform. Our architecture incorporates a load balancer that distributes the computational load across the platform resources, and monitors the QoS the platform delivers. If this deviates from that specified in the SLA, so as to violate it, the platform is reconfigured dynamically in order to incorporate additional resources from the cloud. In contrast, if the SLA is honored and platform resources result unused, platform reconfiguration occurs to release those unused resources.

Cost-driven scheduling of grid workflows using Partial Critical Paths

Abstract: Recently, utility grids have emerged as a new model of service provisioning in heterogeneous distributed systems. In this model, users negotiate with providers on their required Quality of Service and on the corresponding price to reach a Service Level Agreement. One of the most challenging problems in utility grids is workflow scheduling, i.e., the problem of satisfying users' QoS as well as minimizing the cost of workflow execution. In this paper, we propose a new QoS-based workflow scheduling algorithm based on a novel concept called Partial Critical Path. This algorithm recursively schedules the critical path ending at a recently scheduled node. The proposed algorithm tries to minimize the cost of workflow execution while meeting a user-defined deadline. The simulation results show that the performance of our algorithm is very promising.

Monitoring, Prediction and Prevention of SLA Violations in Composite Services

Abstract: We propose the PREvent framework, which is a system that integrates event-based monitoring, prediction of SLA violations using machine learning techniques, and automated runtime prevention of those violations by triggering adaptation actions in service compositions. PREvent improves on related work in that it can be used to prevent violations ex ante, before they have negatively impacted the provider's SLAs. We explain PREvent in detail and show the impact on SLA violations based on a case study.

Platform-as-a-Service Architecture for Real-Time Quality of Service Management in Clouds

Abstract: Cloud computing offers the potential to dramatically reduce the cost of software services through the commoditization of information technology assets and on-demand usage patterns. However, the complexity of determining resource provision policies for applications in such complex environments introduces significant inefficiencies and has driven the emergence of a new class of infrastructure called Platform-as-a-Service (PaaS). In this paper, we present a novel PaaS architecture being developed in the EU IST IRMOS project targeting real-time Quality of Service (QoS) guarantees for online interactive multimedia applications. The architecture considers the full service lifecycle including service engineering, service level agreement design, provisioning and monitoring. QoS parameters at both application and infrastructure levels are given specific attention as the basis for provisioning policies in the context of temporal constraints. The generic applicability of the architecture is being verified and validated through implemented scenarios from three important application sectors (film post-production, virtual augmented reality for engineering design, collaborative e-Learning in virtual worlds).

Method and system for providing a cdn with granular quality of service

Abstract: In a method of providing granular quality of service in a hybrid content distribution network of classical distribution in a network via client-server plus very distributed mechanisms operating peer to peer inside the network, content is replicated in a large number of endpoint nodes, some of which are CPEs of broadband subscribers, and backed by a few storage servers to ensure content availability. Traffic is delivered by a mixture of P4P for choice of seeds and selection of good neighborhoods for quick content download. The ISP uses the unsold physical capacity of the link for CDN service and other underutilized resources, and enforces seeding at many nodes including broadband subscriber CPEs. By having a large farm of nano-datacenters distributed across the network, including the premises of broadband customers, the ISP can maintain and run a CDN. A tracker determines where to seed the content, depending on the number of broadband subscribers requesting the content, the geographical distribution of requested content, and the Service Level Agreement between content providers and the ISP. The tracker can seed a sufficient number of nodes to ensure redundancy.

SLA-driven Elastic Cloud Hosting Provider

Abstract: It is clear that Cloud computing is and will be a sea change for the Information Technology by changing the way in which both software and hardware are designed and purchased. In this work we address the use of this emerging computing paradigm into web hosting providers in order to avoid its resource management limitations. Thanks to the Cloud approach, resources can be provided in a dynamic way according with the needs of providers and end-users. In this paper, we present an elastic web hosting provider, namely Cloud Hosting Provider (CHP), that makes use of the outsourcing technique in order to take advantage of Cloud computing infrastructures for providing scalability and high availability capabilities to the web applications deployed on it. Furthermore, we pursue the main goal of maximizing the revenue earned by the provider through both the analysis of Service Level Agreements (SLA) and the employment of an economic model. The evaluation exposed demonstrates that the system proposed is able to properly react to the dynamic load received by the web applications and it also achieve the aforesaid revenue maximization of the provider by performing an SLA-aware resource (i.e. web servers) management.

A cloud agency for SLA negotiation and management

Abstract: Resources management facilities, based on service level agreements, are needed in the Cloud in order to negotiate a collection of inter-connected and virtualized computers between resource providers and consumers. In this paper we present the architectural design of a system named Cloud Agency which aims to respond to this need and to offer added value to the existing Cloud services. This system is in charge to broker the collection of Cloud resources from different providers that fulfills at the best the requirements of user's applications. The user is able to delegate to the Agency the necessary checks of the agreement fulfilment, the monitoring of resource utilization and eventually necessary re-negotiations.

Method and system for guaranteed end-to-end data flows in a local networking domain

Abstract: A local manager in a local networking domain may configure, in conjunction with one or more switching devices, a plurality of network and/or switching devices to establish guaranteed end-to-end data flows in the local networking domain for servicing applications and/or processes running in the network devices. The network devices supporting or using guaranteed end-to-end data flows may determine data flow requirements for each serviced application, and may communicate the determined data flow requirements to switching devices supporting the local manager, for configuring the guaranteed end-to-end data flows. Data flow requirements may comprise bandwidth, quality of service (QoS), security, and/or service level agreement (SLA) related parameters. The network devices may allocate networking resources to guarantee the end-to-end data flow for each application running in each network device. Data flow routing tables maybe maintained and/or updated based on use of existing guaranteed end-to-end data flows.

Optimization of Resource Scheduling in Cloud Computing

Abstract: Resource scheduling based on SLA (Service Level Agreement) in cloud computing is NP-hard problem. There is no efficient method to solve it. This paper proposes a new method to solve the problem by applying stochastic integer programming for optimal resource scheduling in cloud computing. Applying Gr\"{o}bner bases theory for solving the stochastic integer programming problem and the experimental results of the implementation are also presented.

SLA★: An abstract syntax for Service Level Agreements

Abstract: This paper describes SLA★, a domain-independent syntax for machine-readable Service Level Agreements (SLAs) and SLA templates. Historically, SLA★ was developed as a generalisation and refinement of the web-service specific XML standards: WS-Agreement, WSLA, and WSDL. Instead of web-services, however, SLA★ deals with services in general, and instead of XML, it is language independent. SLA★ provides a specification of SLA(T) content at a fine-grained level of detail, which is both richly expressive and inherently extensible: supporting controlled customisation to arbitrary domain-specific requirements. The model was developed as part of the FP7 ICT Integrated Project SLA@SOI, and has been applied to a range of industrial use-cases, including; ERP hosting, Enterprise IT, live-media streaming and health-care provision. At the time of writing, the abstract syntax has been realised in concrete form as a Java API, XML-Schema, and BNF Grammar.

System and method for reactive and deliberative service level management (SLM)

Abstract: Method and apparatus for service level management, wherein business processes are composed of services. A state of the service is defined by one or more service parameters, and the service parameters depend upon performance of network components that support the service, e.g., component parameters. The state of the service may depend, for example, on a collection of service parameter values for availability, reliability, security, integrity and response time. A service level agreement is a contract between a supplier and a customer that identifies services supported by a network, service parameters for the services, and service levels (e.g., acceptable levels) for each service parameter.

SLA-Driven Dynamic Resource Management for Multi-tier Web Applications in a Cloud

Abstract: Current service-level agreements (SLAs) offered by cloud providers do not make guarantees about response time of Web applications hosted on the cloud. Satisfying a maximum average response time guarantee for Web applications is difficult due to unpredictable traffic patterns. The complex nature of multi-tier Web applications increases the difficulty of identifying bottlenecks and resolving them automatically. It may be possible to minimize the probability that tiers (hosted on virtual machines) become bottlenecks by optimizing the placement of the virtual machines in a cloud. This research focuses on enabling clouds to offer multi-tier Web application owners maximum response time guarantees while minimizing resource utilization. We present our basic approach, preliminary experiments, and results on a EUCALYPTUS-based testbed cloud. Our preliminary results shows that dynamic bottleneck detection and resolution for multi-tier Web application hosted on the cloud will help to offer SLAs that can offer response time guarantees.

Cloud Economics: Principles, Costs, and Benefits

Abstract: Cloud computing is an important next step in the trend toward inexpensive and universal access to information and sophisticated computing resources that help close the digital divide between the computer haves and have-nots. In cloud computing, the end-users can access fully functional software and services online at little or no cost using inexpensive computers or mobile communication devices that connect them via the Internet. Innovative service providers no longer need to own and maintain development or production infrastructures and can automatically scale their production operations to meet growing demand much more easily and economically than possible with internal data centers, traditional hosting, or managed services arrangements. The cloud’s inherent ability to dynamically scale up or scale down the infrastructure commitment as demand changes on a pay-as-you-go basis has a positive impact on the service provider’s overhead costs, energy costs, and in reducing its carbon footprint.

LAYSI: A Layered Approach for SLA-Violation Propagation in Self-Manageable Cloud Infrastructures

Abstract: Cloud computing represents a promising computing paradigm where computing resources have to be allocated to software for their execution. Self-manageable Cloud infrastructures are required to achieve that level of flexibility on one hand, and to comply to users' requirements specified by means of Service Level Agreements (SLAs) on the other. Such infrastructures should automatically respond to changing component, workload, and environmental conditions minimizing user interactions with the system and preventing violations of agreed SLAs. However, identification of sources responsible for the possible SLA violation and the decision about the reactive actions necessary to prevent SLA violation is far from trivial. First, in this paper we present a novel approach for mapping low-level resource metrics to SLA parameters necessary for the identification of failure sources. Second, we devise a layered Cloud architecture for the bottom-up propagation of failures to the layer, which can react to sensed SLA violation threats. Moreover, we present a communication model for the propagation of SLA violation threats to the appropriate layer of the Cloud infrastructure, which includes negotiators, brokers, and automatic service deployer.

Cloud Broker and Procurement System and Method

Abstract: A cloud broker and procurement system and method is closed. In particular embodiments, the method includes receiving an offer of a computing resource from each of a plurality of providers. The method further includes receiving, from each of the plurality of providers, a service level agreement associated with each respective offered computing resource. Additionally, the method includes normalizing each of the service level agreements associated with the offered computing resources. The method further includes receiving a request from a requesting computer for a computing resource and selecting, based at least in part on the normalized service level agreements, one of the providers to provide the requested computing resource. The method also includes transmitting a service match indicator to the client, wherein the service match indicator indicates a time at which the offered computing resource will be utilized, and utilizing the computing resource on the selected provider.

Optimized capacity planning

Abstract: A computer implemented method, system and/or program product determine capacity planning of resources by utilizing a stochastic analysis of application workloads Average workloads, which describe past resource utilization, of each of multiple applications are computed A random sequence of the multiple applications is encoded into a first generation chromosome The first generation chromosome is executed using a set of computing resources in a resource cloud In response to execution of the first generation chromosome on the set of computing resources meeting a predetermined service level agreement (SLA) for the first generation chromosome, the first generation chromosome is scored in accordance with how many computing resources within the set of computing resources are utilized in order to meet the predetermined SLA Next generation chromosomes, derived from the first generation chromosome, are executed and scored until an optimal chromosome, which utilizes the fewest computing resources, is identified and deployed

Dynamic service level agreement for cloud computing services

Abstract: A method for dynamically updating a service level agreement, performed by a cloud computing server, includes storing a preference for service selection, acquiring an actual usage level of a first service provided to a user during a predetermined time period in accordance with a first service level agreement, determining a second service level agreement different from the first service level agreement based on the actual usage level acquired during the predetermined time period, and selecting a second service that satisfies the second service level agreement.

SLA validation in layered cloud infrastructures

Abstract: Cloud computing brings in a novel paradigm to foster ITbased service economy in scalable computing infrastructures by allowing guaranteed on-demand resource allocation with flexible pricing models. Scalable computing infrastructures not only require autonomous management abilities but also the compliance to users' requirements through Service Level Agreements (SLAs). Such infrastructures should automatically respond to changing components, workload, and environmental conditions as well as prevent violations of agreed SLAs. The essential requirements for SLA-based orchestration of services include agile component-based infrastructure to support these orchestrations; proactive validation of SLAs to prevent violations; and business enabling requirements including trust, privacy and breach management to address penalty enforcement, renegotiation and recovery. In this paper we outline a systematic approach that weaves together three different SLA management models, which cater the above mentioned issues by localizing and addressing them at different but interrelated scopes pertaining to resource, infrastructure, and business domains. In our framework Cloud components (e.g., meta negotiator, broker, automatic service deployer) are loosely coupled using SLAs and can be exchanged on demand considering current load, systems failures, and the whole Cloud ecosystem. Thereafter, SLAs are validated based on high level goals (e.g., business rules, VO policies) ensuring trust, privacy, and breach management in layered Cloud infrastructures.

Hardware flow classification for data storage services

Abstract: The techniques introduced here provide a system and method for hardware implemented storage service flow classification using content addressable memory. The techniques described here allow for classification and handling of storage service requests according to service level agreement (SLA) or quality of service (QoS) parameters without consuming valuable storage server resources.

Towards Knowledge Management in Self-Adaptable Clouds

Abstract: Cloud computing represents a promising computing paradigm where resources have to be dynamically allocated to software that needs to be executed. Self-manageable Cloud infrastructures are required to achieve that level of flexibility on the one hand, and to comply to users’ requirements specified by means of Service Level Agreements (SLAs) on the other. Such infrastructures should automatically respond to changing component, workload, and environmental conditions minimizing user interactions with the system and preventing violations of SLAs. However, identification of system states where reactive actions are necessary for the prevention of SLA violations is far from trivial. In this paper we investigate how current knowledge management systems can be used for the prevention of SLA violations in Clouds. First, we define a typical SLA use case and formulate the expected behavior of the knowledge management system in order to prevent possible SLA violations. Second, we investigate different methods for knowledge management, e.g., situation calculus and case based reasoning (CBR). We discuss how these methods match the expected behavior for SLA violation prevention. In particular we examine the CBR method and devise several approaches for knowledge management in Clouds based on CBR. Finally, we evaluate our approach based on the presented use case.

A Real-time Service Oriented Infrastructure

Abstract: The advancements in distributed computing have driven the emergence of service-based infrastructures that allow for on-demand provision of ICT assets. Taking into consideration the complexity of distributed environments, significant challenges exist in providing and managing the offered on-demand resources with the required level of Quality of Service (QoS), especially for real-time interactive and streaming applications. In this paper we propose an approach for providing real-time QoS guarantees by enhancing service oriented infrastructures with coherent and consistent real-time attributes at various levels (application, network, storage, processing). The approach considers the full lifecycle of service-based systems including service engineering, Service Level Agreement (SLA) negotiation and management, service provisioning and monitoring. QoS parameters at application, platform and infrastructure levels are given specific attention as the basis for provisioning policies in the context of temporal constraints

Constraint-conscious optimal scheduling for cloud infrastructures

Abstract: Systems and methods are disclosed to schedule jobs in a cloud computing infrastructure by receiving in a first queue jobs with deadlines or constraints specified in a hard service level agreement (SLA); receiving in a second queue jobs with a penalty cost metric specified in a soft SLA; and minimizing both constraint violation count and total penalty cost in the cloud computing infrastructure by identifying jobs with deadlines in the first queue and delaying jobs in the first queue within a predetermined slack range in favor of jobs in the second queue to improve the penalty cost metric.

Reputation-Based QoS Provisioning in Cloud Computing via Dirichlet Multinomial Model

Abstract: In Cloud computing, users with different service requirements often need to negotiate with service provider via Service Level Agreement (SLA). The unique pay-as-you-go billing way in Cloud computing challenges resource provisioning for service providers. In this paper, based on the Dirichlet multinomial model, we present an efficient reputation-based QoS provisioning scheme, which can minimize the cost of computing resources, while satisfying the desired QoS metrics. Unlike the previous counterparts, we consider the statistical probability of the response time as a practical metric rather than the typical mean response time. Numerical results show the efficiency and effectiveness of the proposed scheme.

Multi-Tenant, Secure, Load Disseminated SaaS Architecture

Abstract: The availability of high speed internet has diversified the way we used to intermingle with each other. The emergence of social networks and interactive web applications has left a dent in existing software and service delivery models. Software vendors now not only focus on functionality but also have to cater delivery model of their software. On-demand and ubiquitous accessibility has become an inimitable selling point for software vendors. In the last few years we have witnessed a term “Cloud computing” thronging blogs and search engines. Cloud computing is on-demand service delivery; services ranging from Infrastructure, Platform and Software. With the materialization of Amazon Cloud Computing Service we have seen exponential increase in interest of business as well as research community in Cloud computing Orchestra. Now technological oracles are offering their software in Cloud as Software as a Service (SaaS). Every service provider is laying on line to gain competitive advantage over each other, there is need to delineate development guideline for SaaS. Without any doubt security is one of the main concerns for Cloud computing environment but unfortunately in the mist of security issues general recommendations for efficient Cloud has faded away. In this paper we have proposed a Cloud computing architecture focusing SaaS, which provides general specifications for SaaS design and for services implemented in it.

SLA-Aware Dynamic Bandwidth Allocation for QoS in EPONs

Abstract: The Ethernet passive optical network (EPON) is one of the most promising broadband access networks. We propose a new dynamic scheduling algorithm, referred to as cyclic-polling-based dynamic bandwidth allocation with service level agreements (CPBA-SLA), for service differentiation that meets the service level agreements between the OLT and ONUs. The proposed dynamic bandwidth allocation (DBA) scheme provides a constant and predictable average packet delay and an improved delay jitter of the expedited forwarding traffic without the influence of load variations. A performance evaluation shows the effectiveness of the proposed DBA scheme.

Database as a service (DBaaS)

Abstract: Modern Web or “Eternal-Beta” applications necessitate a flexible and easy-to-use data management platform that allows the evolutionary development of databases and applications. The classical approach of relational database systems following strictly the ACID properties has to be extended by an extensible and easy-to-use persistency layer with specialized DB features. Using the underlying concept of Software as a Service (SaaS) also enables an economic advantage based on the “economy of the scale“, where application and system environments only need to be provided once but can be used by thousands of users. Within this tutorial, we are looking at the current state-of-the-art from different perspectives. We outline foundations and techniques to build database services based on the SaaS-paradigm. We discuss requirements from a programming perspective, show different dimensions in the context of consistency and reliability, and also describe different non-functional properties under the umbrella of Service-Level agreements (SLA).

Enforcing SLAs in Scientific Clouds

Abstract: Software as a Service (SaaS) providers enable the on-demand use of software, which is an intriguing concept for business and scientific applications. Typically, service level agreements (SLAs) are specified between the provider and the user, defining the required quality of service (QoS). Today SLA aware solutions only exist for business applications. We present a general SaaS architecture for scientific software that offers an easy-to-use web interface. Scientists define their problem description, the QoS requirements and can access the results through this portal. Our algorithms autonomously test the feasibility of the SLA and, if accepted, guarantee its fulfillment. This approach is independent of the underlying cloud infrastructure and successfully deals with performance fluctuations of cloud instances. Experiments are done with a scientific application in private and public clouds and we also present the implementation of a high-performance computing (HPC) cloud dedicated for scientific applications.