Transparent dynamic reconfiguration for CORBA

Abstract

Distributedsystems with high availability requirements have to support some form of dynamic reconfiguration. This means that they must provide the ability to be maintained or upgraded without being taken off-line. Building a distributed system that allows dynamic reconfiguration is very intrusive to the overall design of the system, and generally requires special skills from both the client and server side application developers. There is an opportunity to provide support for dynamic reconfiguration at the object middleware level of distributed systems, and create a dynamic reconfiguration transparency to application developers. In this paper, we propose a Dynamic Reconfiguration Service for CORBA that allows the reconfiguration of a running system with maximum transparency for both client and server side developers. We describe the architecture, a prototype implementation, and some preliminary test results.

ReDAC -- Dynamic Reconfiguration of Distributed Component-Based Applications with Cyclic Dependencies

“…Existing reconfiguration approaches do not yet consider synchronisation between application threads (in most cases because no multi-threading is supported). Almeida et al [1] require that there are no dependent non-re-entrant threads in an application. In case of common synchronization objects among application threads our algorithm (and the other algorithms) could run into a deadlock.…”

“…Almeida et al [1] introduce the concept of selective queuing, which is a mechanism to decide for each message exchange between two nodes if a message must be queued or processed. By forwarding implicit parameters (node ID's) with each message it is possible to decide if a message stems from a node included in the set of nodes affected by a dynamic reconfiguration.…”

A Framework for Adaptive Mobile Objects in Heterogeneous Environments

“…Almeida et al propose a dynamic reconfiguration service for CORBA [16]. This service is able to upgrade objects without taking them offline by entailing operations for migration, replacement, addition and removal of objects.…”

Task distribution based adaptation in mobile patient monitoring systems

“…The development on component-based software engineering, e.g., CORBA [AVSN01], enterprise JavaBean [RAC + 02], have enabled efficient implementation of dynamic reconfiguration systems. In [Weg03], a dynamic reconfiguration mechanism is proposed for component-based middleware.…”

“…In order to maintain state consistency during a dynamic reconfiguration, a threestage reconfiguration approach has to be followed [AVSN01]: (1) drive system to a safe state in which to-be-reconfigured components are self-contained and stable and none of them is involved in any interaction; (2) detect if a safe state has been reached; and (3) apply reconfigurations. Following this general approach, we define a sequential seven-step scheme to create dynamic reconfiguration plan.…”