The service model for a hosted service in Windows Azure is specified in two XML files: the service definition file (ServiceDefinition.csdef) and the service configuration file (ServiceConfiguration.cscfg). These files are part of the Windows Azure project.
The service definition file specifies the roles used in the hosted service. There can be at most five roles in a hosted service. For each role, the service definition file specifies: the instance size; the available endpoints; the public key certificates; the pluggable modules used in the role; the startup tasks; the local resources; and the runtime execution context. The service definition file also contains the declaration of any custom configuration settings used in a role. For a web role running full IIS, the service definition file contains the IIS configuration.
All instances of a role have the same size, chosen from extra-small to extra-large. Each role may specify a number of input...