Authors:
            
                    Antonella Longo
                    
                        
                    
                    ; 
                
                    Marco Zappatore
                    
                        
                    
                     and
                
                    Mario Bochicchio
                    
                        
                    
                    
                
        
        
            Affiliation:
            
                    
                        
                    
                    University of Salento, Italy
                
        
        
        
        
        
             Keyword(s):
            SLA Management, SLA Measurement, SLA Composition, SLA Design.
        
        
            
                Related
                    Ontology
                    Subjects/Areas/Topics:
                
                        e-Business
                    ; 
                        Enterprise Engineering
                    ; 
                        Enterprise Information Systems
                    
            
        
        
            
                Abstract: 
                Cloud Services (CSs) nowadays experience constantly improving successes in IT scenarios. Dynamic
allocation of network, storage and computational resources, the hiding of visibility of internal IT
components, as well as the pay-per-use paradigm are becoming more and more widespread ways to provide
and consume services. The complexity of CSs is often due to service chains into which third-party services
are aggregated in order to satisfy user requests. This confirms the need of modeling both contracts and
corresponding Service Level Agreements (SLAs) referring to services provided to customers. Similarly,
time-related variability issues in CSs require run-time performance monitoring and reporting solutions
capable of comparing SLAs and feeding requesters with effective resource reservation and allocation
policies. A detailed analysis in contracts and SLAs management has revealed a lack of expressivity in SLA
specification and a consequent inadequacy in tools for describing and managin
                g SLAs and contract
composition. Therefore, we propose an extension of WSLA, a widely known SLA description language. We
aim at modeling contracts and SLAs with additional details to support contract owners during service
composition and its monitoring. The proposed approach has been adopted to develop and validate a tree-graph-based tool, to simplify SLA and contract composition.
                (More)