Specifying and monitoring guarantees in commercial grids through SLA

Grid computing has relied on "best effort" as the guiding principal of operation. However, commercial grids need to provide much stricter guarantees. These guarantees have to be specified in terms of service level agreements and have to be monitored and assured We propose an architecture for specifying and monitoring service level agreements to achieve the above. The architecture relies on a network of communicating proxies each maintaining SLAs committed within the administrative domain of the proxy. SLAs are either negotiated between or specified to management proxies, and they are responsible for automated monitoring of data and for triggering evaluations of the registered SLAs. An unambiguous and flexible language for formalizing SLAs is presented to achieve the above. The management proxy allows reasoning about the overall status of SLAs related to an application context across multiple administrative domains by contacting and querying involved management proxies, obtaining measurement information from multiple proxies, if needed and performing a consolidated SLA evaluation. The process of measurement collection, and SLA evaluation is automated and based on web services technology. The scenario considers HP Utility Data Center as a typical Commercial Grid deployment environment.