The Internet Operating System: Middleware for adaptive distributed computing

Large-scale, dynamic, and heterogeneous networks of computational resources (a.k.a. grids) promise to provide high performance and scalability to computationally intensive applications. To fulfill this promise, grid environments require complex resource management. We propose decentralized middleware-triggered dynamic reconfiguration strategies to enable application adaptation to the constantly changing resource availability of Internet-scale shared computational grids. As a proof of concept, we present a software framework for dynamically reconfigurable distributed applications. The Internet Operating System (IOS) is a middleware infrastructure which aims at freeing application developers from dealing with non-functional concerns while seeking to optimize application performance and global resource utilization. IOS consists of distributed middleware agents that are capable of interconnecting themselves in various virtual peer-to-peer topologies. IOS middleware agents: 1) profile application communication patterns; 2) evaluate the dynamics of the underlying physical resources; and 3) reconfigure application components by changing their mappings to physical resources through migration and by changing their granularity through a split and merge mechanism. A key characteristic of IOS is its decentralized coordination, thereby avoiding the use of global knowledge and thus enabling scalable reconfiguration. The IOS middleware is programming model-independent: we have implemented an actor programming model interface for SALSA programs and also a process programming model interface for MPI programs. Experimental results show that adaptive middleware can be an effective approach to reconfiguring distributed applications with various ratios of communication to computation in order to improve their performance, and more effectively utilize grid resources.