Upgrading Distributed Applications with the Version Manager

摘要

Developers and managers of distributed systems today face a difficult choice. To provide for the evolution of their systems, they can either require that the software running on all nodes is interoperable, or they can shut down the entire system when an upgrade is required. The former complicates the life of system developers, while the latter annoys users. The authors propose Version Manager, a middle ground between these approaches. Version Manager is an upgrade framework that limits the extent of support required for interoperability, while also providing availability during upgrades. They evaluate the feasibility of their approach by applying it to two existing distributed systems: the Cooperative File System and IRISLOG. Their proposal enables the upgrade of these systems while maintaining system availability, and without requiring code modifications.