| Sommario: | Since its introduction, the Grid computing paradigm has been
widely adopted both in scientific and also in industrial areas. The main advantage of the Grid computing paradigm is the ability to enable, in a
transparent way, the sharing and the coordination of several heterogeneous
and large-scale distributed resources belonging to different institutional
domains. One of its limitation is the lack of facilities for executing
services. In fact, Grid computing has been traditionally used and improved
for running computational-intensive or data-intensive applications. A
service differs from this kind of applications in that it usually waits
for requests from clients and replies with useful information; moreover, a
service is typically subjected to some predefined constraints, called
Service Level Agreement (SLA), including both temporal and performance
restrictions. In this paper we present the TAAROA middleware, a software
system that tries to extend the traditional target of the Grid computing
paradigm to include the service concept. It attempts to accomplish its
goal by using the virtualization technology. By abstracting the hardware
and software resources of a computer, virtualization brings to TAAROA two
important benefits: (1) the encapsulation of the service runtime
environment, and (2) the possibility, through the migration facility, to
move a service from the computer where it is running to another one that
hopefully reduces the risk of violating some of the SLA constraints. In
the current version of TAAROA middleware there is no explicit mechanism
for achieving the level of a service as defined by the related SLA; this
means that actually TAAROA is only able to provide a best-effort service. |
