Research On Dynamic Application Update For PaaS Platform

PaaS platform provides high availability and fault tolerance for the applications deployed upon it. As is known, applications have to be constantly updated for fault correction and functionality enhancement. PaaS only supports off-line application up-date, which is not acceptable for mission critical systems. Respecting on the limitation of updating in current PaaS platform, we proposed a software dynamic update oriented PaaS platform referring to the existing technology of dynamic update. This frame-work is mainly focused on addressing the problems in software dynamic update like distributive transaction management and dependency management. We implemented the framework on top of Cloud Foundry and conducted experiments to evaluate its effectiveness.The work can be summarized as follows:1. Based on analyzing the limitation of PaaS supporting application dynamic up-date, we proposed a generic dynamic-update-enabled extension framework for PaaS with resort to existing critical techniques on software dynamic update.2. We proposed a distributed application transaction extension framework. There-fore applications are able to notify the transaction manager upon transaction changes. Also we formulated a distributed transaction-based sticky forwarding mechanism to manage distributed transactions.3. We proposed a maintenance mechanism for application dependencies. We col-lect application dependencies on receiving update requests, and use the extended distributed communication mechanism to propagate applications’ dependencies to dependent applications, so that each application can decide the safe point for dynamic update accruing to its local information.4. Based on our solution, we extended the Cloud Foundry platform to support the deployment, management and on-line evolvement of applications. In addition, we selected a third-party application to experimentally evaluate the correctness and performance of our extended PaaS platform.