Information Technology Reference
In-Depth Information
In 2002, the Globus project and IBM initiated a development effort to align Grid
Computing with Web Services and the SOC paradigm (Talia 2002). Out of this
initiative, the Open Grid Service Architecture (OGSA) was developed. According
to Foster et al. (2002), the OGSA is an extensible set of services which are provided
by Grids. In more detail:
“Building on concepts and technologies from both the Grid and Web Services communities,
OGSA defines a uniform exposed service semantics (the
Grid Service
); defines standard
mechanisms for creating, naming, and discovering transient Grid service instances;
provides location transparency and multiple protocol bindings for service instances; and
supports integration with underlying native platform facilities.” (Foster et al. 2002)
The Open Grid Service Architecture is a layered architecture with clear separation
of the functionalities of each layer (see fig. 3.8). Core layers are OGSI - Open Grid
Service Infrastructure and OGSA platform services. The platform services estab-
lish a set of standard services including policy, logging, service level management,
and other networking services. The core elements of OGSA are Grid Services, i.e.
Grid-related Web Services that provide a set of well-defined interfaces and follow
specific conventions (Talia 2002).
Applications
OGSA Defined Services
Web Services
OGSA Enabled
OGSA Enabled
OGSA Enabled
OGSA Enabled
OGSA Enabled
OGSA Enabled
Security
Workflow
Database
File System
Directory
Messaging
OGSA Enabled
OGSA Enabled
OGSA Enabled
Servers
Storage
Network
Fig. 3.8:
Overview of the OGSA Architecture
The convergence of Grid Computing with Service-oriented Computing means that
Grid functionality is provided in form of services. The application of the service-
oriented computing paradigm to Grid Computing has several advantages: First of
all, it brings Grid in line with technologies currently adopted on a broad scale by
companies. In addition, the service-oriented Grid paradigm offers the potential
to provide a fine-grained virtualization of the available resources to significantly
increase the versatility of a Grid (Smith et al. 2006). It also provides a binding
element among Grid specific services on the hardware level and application serv-
ices.
