Cloud computing raises many issues about Virtualization and Service-Oriented Architecture (SOA). Topics to be addressed regarding services in Cloud computing environment include contractualization, monitoring, management, and autonomic management. Cloud computing promotes a \"Pay-per-use\" business model. It should enable to reduce costs but requires flexible services than can be adapted, e.g., to load fluctuations. This capability is achieved thanks to Service Level Agreement (SLA) monitoring and analysis (i.e., compliance checking), and to autonomic reconfiguration performed according to the analysis results. SLAs contractualize the services and the cloud virtualized environment itself.