Research On Dynamic Configuration Technology In The DDS-oriented Distributed System

With the development of distributed technology, especially after Internet became the runtime environment of dominant software the openness and dynamics of internet intensify the variability and complexity of software system. At the same time, information real-time requirement gradually increased in some real-time system or long-running mission-critical system, which is difficult to achieve the level of system's demand about real-time, robustness, scale and efficiency. Dynamic configuration technology is currently a hot topic in the research area. Dynamic configuration is the process of update the system configuration during running time. It provides dynamic and unpredictable adjustments to system. DDS (Data Distribution Service) provides low latency, high throughput and real-time performance of data exchange service and is widely used in aerospace, defense, distribution, simulation and other fields. The real-time of DDS require that those DDS-oriented distributed system must be updated online. The research of dynamic configuration in DDS-oriented distributed system becomes urgent.This paper analyzes the dynamic configuration mechanism, introduces the reflection theory, and then proposes the structure of the Dynamic Configuration Platform for DDS-oriented distributed system. We realized the dynamic configuration platform and completed the component distribution dynamically at the end of the paper.Firstly, the paper analyzes the basic theory of dynamic configuration in the component-based distributed system, introduces the Data-Centric Publish-Subscribe mechanism of DDS, uses the reflection theory, proposes the DCP4DDS structure and introduces every part of DCP4DDS.Secondly, this paper puts forward the dynamic configuration algorithms, combining with the system consistency. Dynamic configuration is a kind of "invasive" process. Therefore, the system integrity during the reconfiguration process is one of the key problems of dynamic configuration. This paper designed four algorithms based on the guarantee of system integrity, including component addition, component deletion, component replacement and component migration. The processes of those algorithms are described and their accuracy is analyzed.Finally, the proposed DCP4DDS is realized. Component deployment design tool offers a graphical interface by which the system managers can create dynamic configuration intentions. And the DCP4DDS implements dynamic reconfiguration for the DDS-oriented distributed system.