An Autonomic SLA Monitoring Framework Managed by Trusted Third Party in the Cloud Computing

Introduction

The revolutionary technology of Cloud Computing offers a scalable and flexible paradigm where infrastructure, platform, and software are offered to users in the form of services. The management of such environment is inherently complex due to the large-scale number and heterogeneity of resources and the increasing number and types of services a cloud must deliver over the Internet. Combined with a rapidly increasing number of cloud-based services, this complexity generated a pressing request for effective and efficient monitoring solutions. The provisioning of these computing services by cloud providers are regulated by Service Level Agreements (Maarouf, Marzouk, Haqiq, & El Hamlaoui, 2014), which present an important element that provides some degree of assurance. As of now, the differentiating elements between CC solutions are Quality-of-Service and the SLAs guarantee provided by the service providers. Any SLA mainly describes two things: the different Service Level Objectives (SLO) in terms of values for QoS metrics and the penalties to be applied if the objectives have not been accomplished (Maarouf, Marzouk, & Haqiq, 2015). These properties need to be measurable and must be monitored during the provision of the service that has been agreed upon in the SLA (Maarouf, El Hamlaoui, Marzouk, & Haqiq, 2015).

Within the CC concept, SLA monitoring is a task of paramount importance for both cloud service provider (CSP) to avoid penalties if the SLA terms are violated and for cloud service consumer (CSC) to be aware of the status and quality of their running services. Moreover, a violation of an SLA may cause a cascading effect on the dependent services. Thus, may be affecting the overall composition and degrading the overall system performance. For that reason, a trusted third-party monitoring services is required for this, as a consumer can never prove by itself that an SLA was (partially) or totally violated. The participation of a TTP is 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. We argue that establishing and monitoring SLA violations in real-time has become a critical issue for CC. Indeed, it is mandatory to monitor the SLA terms to determine whether they are achieved or violated. SLA monitoring is essential for both CSP to avoid penalties if the SLA terms are violated and for CSC to be aware of the status and quality of their running services. Moreover, a violation of an SLA may cause a cascading effect on the dependent services. Thus, may be affecting the overall composition and degrading the overall system performance. Furthermore, a client can never prove by itself that an SLA was violated.

This raises the following questions: (i) How to describe the SLA terms between CSP and CSC, such as service levels, penalties in case of SLA violation, etc. (ii) How to provide guarantees on cloud QoS monitoring and detection of SLA violation? How to create a fair competitiveness between providers and hence improve service performance and the reliability in the cloud?