|By William Vambenepe||
|August 3, 2004 12:00 AM EDT||
Enterprise services are created by combining infrastructure services, applications, and business processes. To be able to adapt quickly to business changes, enterprise IT must evolve from management of individual resources to management of interrelated services. This will be achieved through the development of composable and modular standards that expose the management capabilities of the building blocks of enterprise services. The Web services platform is an enabler of this transformation: a Web services-based management infrastructure provides a channel that is appropriate for dynamic resource provisioning, allocation, and configuration - often called utility computing.
We can consider this management infrastructure as a four-layered architecture. Starting at the foundation layer, the work on the base Web services infrastructure is far from over. First, until WSDL 2.0 is widely deployed, designers have to compose around the deficiencies of WSDL 1.1, such as the lack of portType inheritance. Second, there is still no standard for referencing Web services. Finally, key specifications such as WSRF (Web Services Resource Framework) and WSN (Web Services Notification), without which people were left to reinvent Web services interfaces to access stateful resources, have only recently reached the standards community. These issues are being resolved and a set of building blocks for accessing resources through an SOA (service-oriented architecture) is shaping up. It is critical that these building blocks be modular and composable to allow incremental adoption and separation of concerns.
Moving from the foundation to the management protocol layer, the OASIS WSDM (Web Services Distributed Management) technical committee, through its MUWS (Management Using Web Services) specification, is the key articulation point between the base Web services architecture and utility computing. Both the IT management community and the Grid community rely on MUWS. It defines how to express and exercise manageability capabilities through Web services, putting in place a management channel that is more interoperable and accessible than ever before.
Next is the modeling layer. Information models need to be composed so that a service can be represented based on the services that it is assembled from, be they peer or infrastructure services. Since these will be described by different models, the management channel (MUWS) needs to be model-agnostic in order to support a model-centric architecture. For example, CIM (Common Information Model) is a model that focuses on concrete resources. The DMTF WS-CIM subgroup must now open CIM to the Web services platform by developing a standard way to expose CIM-modeled resources through MUWS. Other models provide representations for service security, service-level agreements (SLA), etc. Only by composing these models will, for example, an auction service SLA be adequately managed as it depends on a combination of the performance of the servers on which the service runs, the application server that hosts it, the other services (authentication, billing, etc.) that it makes use of, and the business process engine that controls the bidding. Once this model-centric architecture is in place, management actions can be policy-driven through explicit constraints.
Finally, at the top layer, the architecture includes a set of common services for utility computing. They are being defined collaboratively by DMTF (Utility Computing working group) and GGF (OGSA working group).
All the pieces are falling into place but much remains to be done to allow comprehensive management of enterprise services in a model-centric way through Web services standards. While it would be easier to develop an end-to-end model specific to one company's offering, standardization allows the integration of the management capabilities of all the components that compose enterprise services. We must keep the pressure on vendors to deliver modular and composable specifications (for format, function, and protocol) that expose management capabilities of infrastructure services, applications, and business processes in such a way that these capabilities can be composed by the next generation of management applications. These applications will use this to synchronize business and IT and to capitalize on change.