The Virtual Service Abstraction

The VS abstraction treats services that utilize sub-services as if they were a single application executing on its own dedicated server. To create this illusion, a VS is associated with a basic resource context (Figure 3). The resource context summarizes the resource limits and statistics for activities that execute on behalf of the VS (Section 3.2). Figure 3 also shows typical VS members. Section 3.3 discusses how to track this dynamic member set if applications do not manage VS-membership on their own. In Section 3.4 we discuss the seamless integration of the tracking of VS-membership and resource limit enforcement into a gate abstraction. A gate filters entry and exit of system calls that are relevant with respect to VS-membership changes. Section 3.5 explains the gate's response to resource limit violations.