CLARA: A novel clustering-based resource-allocation mechanism for exploiting low-availability complementarities of voluntarily contributed nodes

Abstract

Volunteer Computing is a type of large-scale distributed system formed aggregating computers voluntarily donated by volunteers. These computers are usually off-the-self heterogeneous resources belonging to different administrative authorities (users) that have an uncertain behavior regarding connectivity and failure. Thus, the resource allocation methods in such systems are highly dependent on the availability of resources. On one hand, resources tend to be scarce, but on the other hand, computers exhibiting low availability patterns – which are the most frequent type – are discarded or used at a high cost only when high available nodes are crowded. This paper presents the Complementary Low-Availability Resource-Allocation (CLARA) mechanism, a novel clustering-based resource allocation mechanism that takes advantage of complementarities between nodes with low availability patterns. The combination of them into complementary nodes offers an availability level equivalent to the level offered by a single high-available node. These groups of complementary nodes are maintained using a lazy reassignment algorithm. Consequently, a significant number of nodes with low-availability patterns are considered by the resource allocation mechanism for service placement. Our method has been validated over a simulation environment of a real volunteer network. The analysis of the results shows how our mechanism maximizes the use of poor quality computational resources to satisfy the user quality requirements while minimizes the number of USs replicas reassignments between nodes. As well, the capacity of the system for providing user services is highly increased while the load of the high-available nodes is remarkably reduced.