Adil Maarouf

Towards a MDE Approach for the Establishment of a Contract Service Level Monitoring by Third Party in the Cloud Computing

Cloud Computing (CC) marks a new step towards IT infrastructure dematerialization. Cloud provides IT resources, software and hardware, remotely accessible, as a service. The adoption of this model raises a number of challenges, particularly with regard to Quality of the provided services. To cope with a highly dynamic environment such as the CC, it is essential to determine in real time Quality of Service (QoS) to meet consumers SLA (Service Level Agreements) specifications. In this context, agreements (contract) service level form an appropriate solution to specify these QoS guarantees. It specifies one or more service level objectives (SLO), to guarantee that the delivered QoS satisfies the consumer expectations. Monitoring these QoS agreements for the management of the relationships, between, cloud providers and their services customers is an area that attracts the attention of many researchers and industrialists in the cloud. In our work we introduce the concept of monitoring and respect of the QoS, then we present a third party service provider that ensures the respect of the Quality of Service in real-time to guarantee the performance and the reliability of the Cloud.

A review of SLA specification languages in the cloud computing

A Service Level Agreement (SLA) represents an agreement between a cloud provider and cloud customer in the context of a particular service provision. This raises the following question: How to describe the SLA terms between prospective signatories, such as service levels, Quality of Service properties, penalties in case of SLA violation, etc. SLA can be represented by specialized languages for easing SLA preparation, automating SLA negotiation, adapting services automatically according to SLA terms, and reasoning about their composition. Therefore, the aim of this work is to present a comprehensive review of how SLAs are created, managed and used in web services and cloud computing environment. This paper provides a review of SLA languages specification. Among them the WSLA, WS-Agreement, SLA*, CSLA and SLAC. Then, a comparison of these languages in terms of the requirements is presented, highlighting their strengths and weaknesses.

Practical modeling of the SLA life cycle in Cloud Computing

Research in Service level agreements has been of growing interest in the Cloud Computing field. This is due to its pivotal role in solving the trade-off between the benefit of the provider and the interest of the customer. Every SLA has a life cycle and a life time to be managed. The life cycle of SLA consists of several stages that vary according to the SLA. In this paper, we present SLA life cycle in light of the cloud computing domain. The presented SLA life cycle define the sequence of changes of the SLA from the perspective of all parties involved in the contract. Some examples for SLA life cycle are illustrated, in order to show the main phases, structures, processes and entities interactions using UML modeling diagrams. The goal of each phase, the participating actors and their role, the potential dependencies as well as the outcomes of each phase are described in this work.

MDE Approach for the Establishment of a Service Level Agreements Monitoring by Trusted Third Party in the Cloud Computing

Establishing and monitoring SLA violations in real-time has become a critical issue for Cloud Computing. In this paper the authors investigate this issue and propose a model to express the SLA contract requirements using Model Driven Engineering MDE, as a mean for establishing service level agreements between a cloud provider and cloud customer in the context of a particular service provision. The participation of a Trusted Third Party TTP may be necessary in order to resolve conflicts between prospective signatories, likewise to monitor SLA violations in real-time in the goal to ensure online monitoring cloud services and provide better than best-effort behavior for clouds. The main focus of this work is firstly to use MDE technology for the creation of the SLA contract and then to integrate TTP that should be able to apply an advanced penalty model that guarantees the performance and the reliability of the Cloud.

A novel penalty model for managing and applying penalties in Cloud Computing

Managing and applying penalties has become a critical issue for Cloud Computing. In this paper we investigate this issue and present the most frequently used definitions of SLA penalty functions. We identify the characteristics of these functions highlighting their strengths and weaknesses. Then we propose a Novel Penalty Model for calculating the penalty cost of the violations, and present a formalization for this penalty definition. An example application will be presented to demonstrate the effectiveness of the proposed approach. Finally, the paper notes some challenges and future research directions.