IBM Corp. and several other vendors recently unveiled three specifications intended to converge Web services and grid computing.
Introduced at the recent GlobusWorld 2004 conference in San Francisco were WS-Notification, a Web services specification for triggering events in IT infrastructure; WS-Resource Lifetime, enabling a user to specify the period during which a resource definition is valid; and WS-Resource Properties, which defines how data associated with a stateful resource can be queried and changed using Web services technologies. All are part of a greater WS-Resource Framework (WSRF).
WSRF designs statefulness into Web services, according to Daniel Sabbah, vice-president of software development and strategy at IBM. “That’s a pretty radical notion for those who have been around Web services for a while,” Sabbah said.
WSRF fills out the Web services stack to be consistent with the Open Grid Services Infrastructure (OGSI), the base grid infrastructure that is part of the Open Grid Services Architecture (OGSA), a set of technical specifications that define a common framework to allow businesses to build grids over a network.
While SW-Notification is part of WSRF, IBM is referring to them separately because of the level of vendor involvement in the two proposals. Other vendors participating in the proposals are Hewlett-Packard, Sonic Software, Tibco, Akamai and The Globus Alliance.
WS-Notification and WSRF provide a standards-based infrastructure for business applications, grid resources and systems management, according to IBM. The effort will provide a publish-and-subscribe messaging model and the ability to model “stateful” resources using Web services. Stateful resources are elements that can be modeled using physical entities such as servers to logical constructs such as business agreements.
Access to stateful resources enables customers to realize business efficiencies including time procurement with multiple suppliers, systems outage detection and recovery, and grid-based workload balancing, according to IBM.
Platform Computing, an independent grid software vendor in Toronto, is a supporter of the OGSA and is pushing the specification as a way to ensure interoperability on heterogeneous systems. It is also actively participating with the Global Grid Forum (GGF), the Globus Alliance, IBM and other partners in the standards process.
Platform’s chief business architect Ian Baird, who holds a seat on the GGF board, said the new WSRF specs will lead to a “significant shift” in the grid world. Before, grid computing was “working within its own isolated world, in a state-based instead of a services-based specification.” He said that it was difficult, if not impossible, for grid services to work in the Web services world, and “many in the Web services community were not embracing OGSI.”
The new grid-friendly Web services specifications point to a “refactoring of the OGSI to a Web services framework . . . . The opportunity is that now we have a more flexible environment to develop grid standards and services moving forward. This is a convergence of Web services and grid.”
Sandra Rogers, program director for Framingham, Mass.-based analyst firm IDC’s Web services software service, agreed. “Web services is allowing for systems to be architected in a more abstract fashion and consumed and networked in a composite fashion, which will then help fuel utility and grid computing.”
Baird said one of the biggest barriers to grid adoption today is the lack of grid-enabled applications. “Not all applications existing today are capable of running in a distributed computing environment; there’s a lot of integration work that needs to be done before that can happen. But this move regarding Web services will enable more applications to be written and grid-enabled in the future.”
Platform has its own commercial distribution of the Globus Toolkit 3.0, an open source bundle of software to enable grid computing. The toolkit includes connectors that provide interoperability with a wide variety of third-party workload management systems and grid offerings. It includes software services and libraries for resource monitoring, discovery and management, plus security and file management.