Service level agreement parameter matching in cloud computing

Due to the large variety in computing resources, Cloud markets often suffer from a low probability of finding matches between consumers’ bids and providers’ asks, resulting in low market liquidity. The approach of service level agreement (SLA) templates (i.e., templates for electronic contracts) is a mean to reduce this variety as it channels the demand and supply. However, until now, the SLA templates used were static, not able to reflect changes in users’ requirements. To address this shortcoming, we introduce an adaptive approach for automatically deriving public SLA templates based on the requirements of market participants. To achieve this goal, we utilize clustering algorithms for grouping similar requirements and learning methods for adapting the public SLA templates to observed changes of market conditions. To assess the benefits of the approach, we conduct a simulation-based evaluation and formalize a utility and cost model. Our results show that the use of clustering algorithms and learning algorithms improves the performance of the adaptive SLA template approach.

Service level agreement (SLA) in cloud computing can be defined as a contractual agreement signed between cloud user and cloud provider in order to manage the quality of service (QoS) parameters which are the fundamental part of SLAs. The current dynamic SLA monitoring approaches have considered the cloud provider's perspective only. To take into consideration the user's perspective; this research proposes a dynamic SLA monitoring approach by generating new SLA terms based on analysing the SLA penalties. A new proposed trade-off mechanism is applied between monthly cost and QoS guarantee values. Thus; we propose a dynamic model for updating QoS parameters of SLA in cloud environment. Java language is used with a QoS measurement dataset to experiment the proposed approach. The current Static SLA (SSLA) approaches are compared with the proposed Dynamic SLA (DSLA) approach. The results of this experimental study show that the number of SLA violations in DSLA are less than the number of SLA violations in SSLA.

Service level agreement (SLA) in cloud computing can be defined as a contractual agreement signed between cloud user and cloud provider in order to manage the quality of service (QoS) parameters which are the fundamental part of SLAs. The current dynamic SLA monitoring approaches have considered the cloud provider's perspective only. To take into consideration the user's perspective; this research proposes a dynamic SLA monitoring approach by generating new SLA terms based on analysing the SLA penalties. A new proposed trade-off mechanism is applied between monthly cost and QoS guarantee values. Thus; we propose a dynamic model for updating QoS parameters of SLA in cloud environment. Java language is used with a QoS measurement dataset to experiment the proposed approach. The current Static SLA (SSLA) approaches are compared with the proposed Dynamic SLA (DSLA) approach. The results of this experimental study show that the number of SLA violations in DSLA are less than the number of SLA violations in SSLA.

Until today, Cloud providers only offer a limited set of non-negotiable service levels to their customers. Most often these service levels are expressed as guarantees for availability together with the offer to have access to a virtualised environment with a certain performance the customer may select from a number of predefined configurations. This simplifies the life of the provider, e.g., in terms of effort to maintain an adequate infrastructure, or regarding the effort for reducing the risk violating Service Level Agreements (SLAs) with its customer. In consequence, the current practice is slanted towards the benefit of the provider and ignores more specific requirements of its customers, e.g. regarding data protection and related guarantees. An analysis of the underlying problems shows two major fields to be worked on for solving the problem: Firstly, each provider uses its own proprietary technology for managing SLAs throughout their life-cycles. However, first standards are available and could be employed allowing the customer to use a single standard interface to negotiate with several providers. Secondly, there is neither a common set of terms to describe Cloud customers requirements regarding the Cloud services requested, nor, the back side of the medal, there is a common set of terms to describe the Quality of Service (QoS) of the Cloud providers' offerings. The focus of the presented work is (i) on the standard technology for negotiating and creating SLAs and (ii) the common terms and metrics describing providers' offerings and customers' requirements. Without these terms mapping the customers' requirements to cloud providers' offerings is a tedious manual and error-prone process and resulting SLAs will remain rudimentary. Additionally, both providers and their customers would benefit from more sophisticated and negotiable Service Level Agreements using existing standards. These SLAs are both (i) binding and monitorable agreements between the customer and the provider covering the customers' requirements and (ii) the basis for a QoS-aware Cloud resource management on the side of the provider including provisioning of physical machines and optimised allocation of virtual machines. Besides more traditional QoS aspects, terms related to Cloud Federation, Data Protection or Security Level Agreements are covered. Customers may use standards compliant agreement templates with the providers' offerings to select suitable providers for starting the negotiation to the extent the provider allows in the template. During the negotiation the provider may take into account the actual degree of capacity utilisation of its infrastructure and active SLAs, and may use the SLA resulting from a successful negotiation to further optimise its infrastructure through application and VM consolidation. The work presented in this thesis covers about a decade of research starting in the environment of Grid computing and ending with today's Cloud computing.

Cloud Computing IT infrastructure has the potential to be particularly suitable for collaborative commerce (c-commerce) applications; because it generally requires less efforts and interferences for development, customization, integration, operation, and maintenance than other traditional IT infrastructures (e.g., on-premises and data centers). However, upgrading c-commerce applications running on traditional IT infrastructures, to run efficiently on cloud computing infrastructure, faces a number of challenges, mainly, lack of effective and reliable architectural model. This paper presents a description of a new architectural model for developing cloud computing based c-commerce applications; which is denoted as cc-commerce model. The model is an basically based on the standard cloud computing model, and it consists of six main components; these are: client, provider, auditor, broker, security and privacy, and communications network. The new model is implemented in a simple and flexible Web-based test tool, namely, the cc-commerce test (3CT) tool, which is used to evaluate the performance of the model through measuring the response times for four different configurations. The analysis of the obtained results demonstrates that the cc-commerce model can provide better response time than equivalent c-commerce models.

Cloud Computing provides higher level services and shared pools of configurable resources with minimal management effort over the internet. Cloud Computing achieves coherence and economic of scale by means of shared resources. The growth of cloud computing depends on the high availability of low cost computers, storage devices and networks as well as hardware virtualization and utility computing. Service Level Agreement (SLA) is a service commitment tool between a cloud service provider and a cloud customer. Using SLA in cloud computing, reduce the chances of disappointing the cloud customer and manage the expectation between the service provider and the customer. The challenge is, it is very difficult to handle all request by the cloud providers at a time during peak hours and to keep up SLA. So when there is an uneven request arrival pattern, the cloud resources may either be underutilized or over-utilized. In order to balance the load, the load balancer plays the major role in cloud computing. The load balancing algorithm equalizes the workload and computing resources in a cloud computing environment. It allows an organization to manage their workload demands by allocating resources among multiple servers and thus it minimizes the response time, minimize the waiting time, maximize the throughput time, maximize the resource utilization and minimize the communication delays of the server by meeting the SLA. The major goal of this study is to review both the existing static and dynamic load balancing algorithms proposed till now and to design and implement a Load balancer that uses a Meta Heuristics approach – Ant Colony Optimization technique to perform balancing the load so that the SLA is met evenly without any issues. Each of the load balancing algorithms is compared with other algorithms theoretically and experimentally one of it is tested with the proposed system using AWS Cloud PaaS (Platform as a Service).

Software as a Service (SaaS) has been developing for over ten years and, is reaching a mature level, where quality and its monitoring and management become significant. Although, SaaS is derived from the ASP model, SaaS background and architecture is different and therefore also SaaS quality management is based on different concepts. This paper is focused on the difference between traditional IT outsourcing and SaaS and proposes a set of quality attributes appropriate for the management of the SaaS quality. 1. Problem Area Service Level Agreement (SLA), a contract between service provider and service customer (Sandholm, T. 2005), is well researched in the IT outsourcing (ITO) context as a way to define the quality of delivered IT service. Now in the era of Software as a Service (SaaS), SLA is also used for the same purpose, but the context has changed - SaaS has different background in comparison to ITO from the business and technological perspective while the SLA structure, content and form should reflect such fact. There is a lack of research literature covering SLA topic in SaaS environment and this is the motivation for this paper. Firstly, we will summarize important literature and discuss the key differences between SaaS and ITO from the several perspectives to distinguish both terms. Then we will focus on the concept of Quality of Service (QoS), important for the structure and content of SLA. The final part of this paper will be dedicated to quality attributes of SaaS service with the objective to formalize the fundamental set of important SaaS quality attributes to be used while creating SLA for SaaS service.

Federation of Cloud services is notably landing interests from both Cloud providers and consumers. Cloud providers nowadays are required to form federations to remain competitive, and sustain their market share. Cloud consumers however seek optimized services from Clouds federation. They strive to maximize their satisfaction level, which is often measured by Quality of Service (QoS). Federations are governed by a mutual contract known as Service Level Agreement (SLA), which both consumers and providers must negotiate, so as to reach an agreement. The focus of this paper is to address issues related to SLA negotiation for the purpose of QoS assurance within federation of Clouds. We define, and specify an automated SLA negotiation model based on Fair Division Game. We evaluate our model using different use cases, and the obtained results proved fairness, and efficiency of the proposed SLA negotiation model in CloudLend.

A Service Level Agreement (SLA) is a legal contract between parties to ensure the Quality of Service (QoS). It specifies one or more service level objectives (SLO), to ensure that the QoS delivered has met customer expectations. However, It becomes hard to guarantee QoS levels and detect SLA violations. Therefore, we propose to use MDE (Model Driven Engineering) to express the SLA contract requirements. This latter, created with a specific modeling language (DSML), will be used harmonically with a Multi-agent systems (MASs) in order to monitor SLA violations in real-time. Indeed, MASs are suitable tools for self-detection of failures and self-monitoring of cloud operations and services, QoS negotiation and SLA management. They are designed to operate in a dynamically changing environment. Our main motivation is firstly to use MDE technology for the creation of the SLA contract and then to integrate MASs in order to control the quality of service contract and guarantee transparency and symmetry with respect to the SLA contract between prospective signatories.

A service level agreement (SLA) is part of a contract between a cloud service provider (CSP) and a cloud service user (CSU) which defines and describes different agreed properties of the service. The negotiation of the SLA between a CSU and a CSP is a pivotal process in the SLA life cycle. An SLA may include many negotiable quality of service (QoS) parameters with each QoS parameter having multiple acceptable values. Different combinations of acceptable values for all QoS parameters grow exponentially as number of QoS parameters and their selectable values increase. Manually negotiating for all of the QoS parameters considering their various options can be an erroneous and diligent task with lower utility. In this paper, a time efficient flip-flop negotiation strategy for the SLAs in cloud services is presented. The flip-flop negotiation strategy is based on a time dependent 3D utility function and on a dynamic concession strategy using the polynomial extrapolation of opponent's concession. This negotiation strategy is useful for time-critical cloud services as it operates with a motive of reaching an agreement at earlier time without compromising over the utility level of the agreement. Moreover, a multi-provider concurrent negotiation method is presented in this work using the flip-flop negotiation strategy. Multiple experiments are performed (using the implementation of flip-flop negotiation strategy) to test the presented work. The results of the experiments enforce the validity of the flip-flop negotiation strategy for such cloud services where time is an important factor during the SLA negotiation process.

This work presents a novel scheme for Service Level Agreements (SLAs) in a service-oriented architecture (SOA). An SLA is a contract that guarantees quality of service (QoS) between service providers and consumers. An SLA can be split into several parts for an SOA system which is consisting of different services. A split SLA is used to guarantee quality of services for one of services in an SOA system. However, these contract rules do not regulate follow-up process in services. SLA violations may occur consequently. For instance, interactions between services are not encrypted because the encryption parameter isn't included in the split SLA contract. Confidential data would be transmitted through unsafe channels. There would be a security issue of SLA Management for follow-up processes in an SOA system. The novel scheme in this work addresses these problems. Using SLAs management proposed in this work can identify the services that consumer needs and split the contracts for follow-up services. SLAs are not only guaranteed between service providers and consumers but also assured in follow-up processes. The proposed method improves the security and completeness of SLA using in an SOA system.

Cloud computing has evolved from the provisioning of virtual machines to the provisioning of complex services, delivered to customers under the terms of Service-Level Agreements (SLAs). SLAs specify the Quality of Service (QoS) that should be provided to customers as well as the billing model. A main concern for cloud service providers is to maintain the agreed SLA terms in order to avoid losses and penalties. Maintaining the SLA in turn requires translating the QoS to configurations of low-level mechanisms, able to enforce the agreed terms. Current systems provide no integrated support for SLA specification, translation, and enforcement. In this paper, we propose an approach for specifying and enforcing SLAs for cloud service providers. The approach covers the creation of SLA templates under a billing model, the design of performance and fault-tolerance QoS assurance mechanisms as well as the translation of QoS to appropriate configurations of those mechanisms. We demonstrate the feasibility of our approach by using the Qu4DS framework for PaaS cloud providers. Moreover, we evaluate the impact of failures on the provider profit. The experiments were carried out on the Grid5000 testbed and demonstrate the effectiveness of ensuring fault tolerance in different scenarios.

By leveraging the Internet, cloud computing allows users to have on-demand access to large pools of configurable computing resources. PaaS (Platform as a Service), IaaS (Infrastructure as a Service), and SaaS (Software as a Service) are three basic categories for the services provided by cloud the computing environments. Quality of service (QoS) metrics like reliability, availability, performance, and cost determine which resources and services are available in a cloud computing scenario. Provider and the user-specified performance characteristics, such as, rejection rate, throughput, response time, financial cost, and energy consumption, form the basis for QoS. To fulfil the needs of its customers, cloud computing must ensure that its services are given with the appropriate quality of service QoS. A “A legally enforceable agreement known as a “Service Level Agreement” (SLA) between a service provider and a customer that outlines service objectives, quality of service requirements, and any associated financial penalties for falling short. We, therefore, presented “A Proactive Resource Supply based Run-time Monitoring of SLA in Cloud Computing”, which allows for the proactive management of SLAs during run-time via the provisioning of cloud services and resources. Within the framework of the proposed work, SLAs are negotiated between cloud users and providers at run-time utilizing SLA Manager. Resources are proactively allocated via the Resource Manager to cut down on SLA violations and misdetection costs. As metrics of performance, we looked at the frequency with which SLAs were broken and the money lost due to false positives. We compared the proposed PRP-RM-SLA model’s simulated performance to the popular existing SLA-based allocation strategy SCOOTER. According to simulation data, the suggested PRP-RM-SLA model is 25% more effective than the current work SCOOTER at reducing SLA breaches and the cost of misdetection.

The size and complexity of Cloud systems are growing more rapidly than expected, and hence, the management of these resources is a major research area. Resource provision with respect to SLA (Service Level Agreement) is directly tied up with customer satisfaction. Failure management is a real-time metric which needs to be addressed by providing continuous availability of resources to the users. This paper contributes to these issues by handling the client without intervention by a human. Continued availability of the client is successfully accomplished by deploying distributed sets of Orchestrators and SLA manager. Ability to deploy nodes remotely and restart nodes is the major area of analysis in this thesis. Monitoring of SLA from a single point for each cloud resource management system is the bottleneck in times of SLA manager failure, which is the brain of the system, and hence we need to overcome the same. Distributing the SLA manager is one of the approaches and which is also being proposed as a solution to the SLA manager failure. SLA Provides a lot of potential in managing cloud resources. In this paper, we build a model to show how WS-Agreement works using JSON. Then, we implement Load Balancing via Grid Gain to make a virtual copy of the same infrastructure as we obtained in SLA. This achieves the jobs to run on virtual machines by eliminating disaster recovery using particle swarm optimization algorithm.

Service Level Agreements (SLA) represents the principal means to control the Quality of Service (QoS). In cloud computing, various advanced SLA strategies are used; some techniques among others try to avoid the SLA violations. Taking into account the cloud consumer contextual parameters is a promising way to predict and avoid costly SLA violations. Therefore, in this paper, we propose a context-aware system for the SLA in order to guarantee the QoS. We create a contextual ontology to introduce the semantic meaning of the cloud consumer contextual parameters. In addition, using reasoning techniques, we (1) predict SLA violations and we (2) choose and apply the corrective actions in autonomous manner. This allows getting a proactive adjustment of the cloud service execution and respecting the SLA parameters.