Resumen
This article explores principles and practices for developing safe customizable middleware, specifically for ensuring composable distributed resource management, or the concurrent execution of multiple resource-management policies in distributed systems. The use of these principles and practices will allow the safe integration of mechanisms for such services as mobility, load balancing, fault tolerance, and end-to-end quality-of-service management. Although reflection is a powerful tool for customizability, its unconstrained use can cause unexpected behavior by applications and violate desired application semantics, the application designer is often totally unaware of effects caused by the underlying middleware infrastructure. The dynamic nature of applications under varying network conditions and traffic requests generally implies resource-management policies should be dynamic and customizable. Composable middleware frameworks implementing cleanly defined meta-architectures enable the customization of applications, protocols, and system services.