Resolving inconsistencies of runtime configuration changes through change propagation and adjustments

A system configuration may be modified at runtime to adapt the system to changes in its environment or for fine-tuning. For instance, a system administrator may change a few entities/attributes in the configuration to improve error recovery and system availability. However, these changes focusing on fine-tuning availability may violate some global system constraints captured in the configuration and therefore break configuration consistency, system properties and operations. This is generally due to the partialness of the changes performed by the administrator who is not aware of all the entities/attributes being in relations with the modified entities/attributes. In this paper, we propose an approach for completing such partial sets of changes at runtime to resolve inconsistencies arising from those partial changes. This adjustment approach consists of the characterization of related entities/attributes and their modification to re-establish the configuration consistency. We achieve this by propagating the changes in the configuration according to the system constraints following the possible impacts of the configuration entities on each other. We aim at minimizing the complementary modifications to control the side-effects of the change propagation as we target the domain of highly available systems.