Web Services Management: A Standards-Based Common Architecture
A Web Services platform would have to be instrumented to send and receive CIM management data at appropriate times. This process is proprietary to the platform and would be done by the platform vendors. However, the concept of interceptors can be used commonly across all platforms. Interceptors act on Web Services requests and respond to generate appropriate management information. They are generally provided by all platforms—each in their own way. Also, in the case of J2EE-based Web Services platforms, generic adapters can be built to simplify conversion of JMX data into CIM formats.
Web Services themselves must also be instrumented to generate or accept relevant management information. However, the platforms are expected to provide simplified interfaces for the service implementations for this purpose.
Transport protocol and data format
- A data model, the Common Information Model (CIM) standard
- An encoding specification, xmlCIM Encoding Specification
- A transport mechanism, CIM Operations over HTTP
WBEM can be extended in a similar fashion as CIM is extended. Hence, WBEM is proposed to be accepted as the standard for Web Services management infrastructure.
More on WBEM: The CIM specification is the language and methodology for describing management data. The extensible CIM schema includes models for Systems, Applications, Networks (LANs), and Devices. The CIM schema will enable applications from different developers on different platforms to describe management data in a standard format so that it can be shared among a variety of management applications. The xmlCIM Encoding Specification defines XML elements, written in Document Type Definition (DTD), which can be used to represent CIM classes and instances. The "CIM Operations over HTTP" specification defines a mapping of CIM operations onto a HTTP protocol that allows implementations of CIM to interoperate in an open, standardized manner and completes the technologies that support WBEM. For more information on WBEM, refer to the DMTF Web site (www.dmtf.org).
The presentation of the management information should be possible in GUI consoles, Web browsers, and/or in PDA consoles. XSL transformation stylesheets can be developed for the CIM/XML data and can be used for dynamically creating HTML or other data for rendering the consoles, browsers, or PDAs. All supported statistics and controls thus can be viewed and operated upon. Another possibility for the presentation layer is to integrate with existing popular management platforms. For example, Web Services management consoles can be integrated with HP OpenviewTM user interfaces. Separation of data from presentation gives the flexibility of having disparate suitable consoles processing the same management data format.
In this first part, we discussed the expectations from a Web Services management platform and the standards relevant to Web Services management. Based on this analysis, in the second part, we will propose a common architecture for Web Services management.
About the Authors
Pankaj Kothari is a technical lead at Hewlett-Packard, India. He has been involved in designing and developing enterprise middleware and Web Services products such as e-speak and HP Application Server. He has also contributed to the architecture and implementation of solutions based on these technologies in various domains for more than five years. He can be reached at firstname.lastname@example.org.
Ravi Trivedi holds a Masters degree in Computer Science from the Indian Institute of Science, Bangalore. He is a technical lead at Hewlett-Packard, Bangalore. He is an expert group member for HP in JAXR (JSR 93) and a committer for open source UDDI4j (www.uddi4j.org). He is involved in developing core Web Services infrastructure and solutions based on these. He can be reached at email@example.com.
The authors would like to acknowledge the contributions of Srinivas Varadarajan, Ashish Chitkara, Manoj Seth, Shyam Bijadi, and Jainendra Kumar at Hewlett-Packard, India for their insightful reviews.
1 Web Services is a term used to describe components and services that are addressable and available using Internet technologies.
2QoS (Quality of Service) specifies a guaranteed response time and throughput level for Web Services users.
3An application service provider (ASP) is a company that offers enterprise access to a Web Services hosting infrastructure that would otherwise have to be located in their own enterprise computers.
4Simple Network Management Protocol (SNMP) is the protocol governing network management and the monitoring of network devices and their functions.
5A Service Level Agreement (SLA) is a contract between a Web Services provider and a customer that specifies, usually in measurable terms, what Quality of Service the Web Services provider will furnish.
6ASN.1 (Abstract Syntax Notation One) is a standard way to describe a message (a unit of application data) that can be sent or received in a network.
Disclaimer : The views expressed here are those of the authors and does not necessarily represent that of Hewlett Packard.
Page 3 of 3