Constraint-based runtime prediction of SLA violations in service orchestrations (extended abstract)

Quality of Service (QoS) attributes, such as execution time, availability, or cost, are critical for the usability of Web services. This in particular applies to service compositions, which are commonly used for implementing more complex, higher level, and/or cross-organizational tasks by assembling loosely-coupled individual service components (often provided and controlled by third parties). The QoS attributes of service compositions depend on the QoS attributes of the service components, as well as on environmental factors and the actual data being handled, and are usually regulated by means of Service-Level Agreements (SLAs), which define the permissible boundaries for the values of the related properties. Predicting whether an SLA will be violated for a given executing instance of a service composition is therefore very important. Such a prediction can be used for preventing or mitigating the consequences of SLA violations ahead of time