Reconfiguring Client-Server Systems

An important aspect of the design of distributed systems is the degree to which it is possible to change their configuration as requirements vary. This paper addresses the issues of reconfiguring server software in a distributed system at run-time. In particular, it is concerned with externally imposed reconfigurations, which avoid explicit interactions with the servers being reconfigured or their clients. An analysis is given showing the conditions under which external reconfigurations are feasible. Mechanisms to achieve external reconfigurations are described, including the use of so-called proxy processes, which have been implemented for the Equus distributed operating environment. Finally, this work is compared with related work, and conclusions are drawn about the advantages and limits to externally-imposed reconfiguration techniques.