Automatic generation of fault-tolerant CORBA-services

Abstract

The Common Object Request Broker Architecture (CORBA) is the most successful representative of an object-based distributed computing architecture. Although CORBA simplifies the implementation of complex, distributed systems significantly, the support of techniques for reliable, fault-tolerant software, such as group communication protocols or replication is very limited in the state-of-the-art CORBA or even fault-tolerant CORBA. Any fault tolerance extension for CORBA components needs to trade off data abstraction and encapsulation against implementation specific knowledge about a component's internal timing behavior, resource usage and interaction patterns. These non-functional aspects of a component are crucial for the predictable behavior of fault-tolerance mechanisms. However, in contrast to CORBA's interface definition language (IDL), which describes a component's functional interface, there is no general means to describe a component's non-functional properties. We present a genetic framework, which makes existing CORBA components fault tolerant. In adherence with a given, programmer-specified fault model, our framework uses design-time and configuration-time information for automatic distributed replicated instantiation of components. Furthermore, we propose usage of aspect-oriented programming (AOP) techniques to describe fault-tolerance as a non-functional component property. We describe the automatic generation of replicated CORBA services based on aspect information and demonstrate service configuration through a graphical user-interface.