 | Level: Intermediate Mr. Brent A. Miller, Senior Technical Staff Member, Autonomic Computing Architecture, IBM
17 Oct 2006 Event-driven systems are an important part of enterprise IT management. The autonomic computing architecture defines an event representation called the Common Base Event that is the basis for the Web Services Distributed Management (WSDM) Event Format (or WEF). As the adoption rate of this event format races forward, IBM found it prudent to generate some best practices for its use; these best practices were published earlier this year. This article offers a perspective on those best practices and discusses their application in IT management systems.
In the last column, I talked about tooling that helps in developing standards-based components for autonomic systems ("if you build it, management will come"). This Edge article continues the focus on the autonomic computing architecture by examining one of the old standbys -- the Common Base Event, an event definition that is IBM's initial implementation of the WSDM Event Format (WEF) standard. Its adoption rate continues to increase and like any robust, extensible specification, WEF and the Common Base Event offer some implementation alternatives. IBM recently published Best Practices for the Common Base Event and Common Event Infrastructure (or CBEBP as shorthand for this article) to describe preferred implementations. In this article, I'll start to detail those best practices and show you what's coming next.
I'll start by describing the Common Base Event and WSDM Event Format and give you a closer look at their relationships. Then I'll look at the purposes of the best practices documentation and give you a peek at what's on the "edge" of autonomic computing event management. (Oh, I mention lots of documentation in this article -- you find links to it in Resources.)
What's a Common Base Event?
According to CBEBP, "an event is an indication of an occurrence -- an indication that something of potential interest has happened." The Common Base Event specification notes that "Events are external, visible manifestations of all systems operations -- they represent the onset, evolution, and conclusion of processes both large and small."
The Common Base Event was developed to represent, in a standard way, the common information that ought to be carried in all event indications. Included in this representation is
- Information about the source of the event (identification and addressing information).
- Information about the reporter of the event (the same information as is specified about the event source in case the reporter is different than the source).
- The situation that the event is reporting (specific, enumerated values that describe the event situation, enabling programmatic interpretation).
- Other event information (which might include associated messages, correlation information, and so on; and must include a time stamp and an event identifier).
The Common Base Event specification provides all of the details about the syntax and semantics of the Common Base Event in the form of an XML schema.
The Common Base Event is supported in numerous IBM products, including many of those associated with event management and problem determination and described on IBM's Problem Determination > Products site, as well as by many other vendors in their product documentation (including products of many of those listed on the Autonomic computing > IBM Business Partners > Partners Web pages. Development tooling for producing, transforming, viewing, and analyzing Common Base Events is available in the IBM Autonomic Computing Toolkit and with the Eclipse Test and Performance Tools Platform (TPTP) project.
So, if I've got the Common Base Event, what's all this I hear about the WSDM Event Format and why do I need that event standard? Let's address that now.
Well, why do I need the WSDM Event Format (WEF)?
Web Services Distributed Management (WSDM) is a manageability/management standard from the Organization for the Advancement of Structured Information Standards (OASIS). In addition to many other properties, operations, and interface definitions, WSDM defines a standard event format -- that event definition, called WSDM Event Format (WEF), is based on the submission of the Common Base Event specification to OASIS by IBM and Cisco. Therefore, WEF shares many of the foundational elements of the Common Base Event, including event source and reporter elements and the Situation element, as well as a time stamp, event identifier, and supplemental event information. WEF updates many of the property names and structure, but is fundamentally consistent with the Common Base Event. IBM considers the Common Base Event to be its initial implementation of WEF and is moving toward the adoption of the WEF standard in WSDM version 1.1 that was ratified in August 2006.
As part of the WSDM 1.1 standard, WEF helps to promote interoperability for event-driven systems. Several IBM products and technologies already support parts of the WSDM standard; see the Autonomic computing > WSDM standards > Products site for details.
Next I'll look at the Common Event Infrastructure, an IBM technology that uses the event standard and is discussed in the CBEBP.
The Common Event Infrastructure
As described in the CBEBP, "The Common Event Infrastructure (CEI) is an embeddable component, incorporated in several IBM products, that supports reporting, persistence, distribution, and interpretation of event data based on the Common Base Event format." Figure 1 shows the structure of CEI.
Figure 1. Common Event Infrastructure
Filtering, persistence, and distribution of events, including a standard way to publish and subscribe to events of interest, are important functions in an event-driven system. CEI provides these functions using a common programming model. As noted in the CBEBP, "CEI is not a product, but rather an IBM component used in several IBM products that provides a programming model to report, persist, and consume Common Base Events, and facilitates the sharing of event information." Because such capabilities are at the heart of event-driven systems, the CBEBP includes best practices for the use of CEI to generate, consume, distribute, filter, and persist events.
Next I'll look at how you can use CEI along with the standard event format.
Using the Common Base Event, WEF, and CEI
The use of a standard event format and a common programming model for event processing both enriches and simplifies event management. Moreover, these capabilities enable both IT and business information to be communicated with events, which helps to break down "silos" among the various roles in a business. This standards-based approach unifies IT events and business events so that end-to-end problem determination can be accomplished more effectively through a concerted effort of all of the involved parties.
Figure 2 illustrates an example of such an event-driven system:
Figure 2. End-to-end problem determination in a standards-based event-driven system
The best practices documentation describes how to use the standard event format and programming model, for both IT events and business events, in such an environment. Let's briefly look at some of the things you can find in the CBEBP.
Introducing: Best Practices
The CBEBP is a comprehensive document that supplements the Common Base Event specification. Intended primarily for those who want to use or learn more about Common Base Events, WEF, and CEI (developers, testers, architects, and others), the document addresses best practices, guidelines, and conventions for:
- How to use Common Base Events in general.
- How to use Common Base Events specifically for problem determination applications.
- How to use Common Base Events specifically for events related to business activities.
- How to use certain programming environments to create and transmit Common Base Events.
- How to use the Common Event Infrastructure to transport events.
In addition to overviews and context for event processing, CEI, problem determination events, and business events, the best practices guide contains specific, concrete instructions, including examples, to guide you in producing and consuming Common Base Events.
In addition, the best practices guide also offers:
- Tips and examples for using IBM technologies such as CEI and the Autonomic Computing Toolkit components in an event-driven system.
- Guidelines and recommendations for the use of optional properties to compose the most meaningful and useful problem determination and business events.
- A property-by-property discussion of the Common Base Event, complete with highlighted tips and best practices for general, problem determination, and business event usage.
- Detailed illustrative scenarios for problem determination and business events, including a scenario that shows how the Common Base Event can help bridge the gap between IT problem determination and business events.
You can find all of this in the Common Base Events Best Practices guide.
On the horizon, teetering on the Edge
The autonomic computing architecture defines the Common Base Event, IBM's initial implementation of the WSDM Event Format industry standard. This common event format is one of the most mature artifacts defined in the autonomic computing architecture and one of the first to be ratified as an open standard. The Common Base Event has been widely adopted, and the Best Practices for the Common Base Event and Common Event Infrastructure supplements the formal specification and offers the "fine tuning" to enhance the value and interoperability of the event standard.
As noted earlier, the Common Base Event is IBM's initial implementation of the industry standard WEF. Owing to the affinity between WEF and the Common Base Event, many of the best practices documented in the best practices guide apply not only to Common Base Events but also to WEF events. In the future, IBM hopes to extend the guide to add specific best practices for the use of WEF events, including considerations for transformations between WEF and Common Base Event formats to accommodate migration and coexistence. The guide is available at developerworks.
The next installment of The autonomic computing edge will discuss methods for developing software that supports the WSDM standard, including WEF.
Acknowledgements
Thanks to the many coworkers from IBM who contributed to the best practices documentation, including Abdi Salahshour, Alan Chivers, Benny Rochwerger, Billy Rowe, Cesar Araujo, Christina Lau, David Enyeart, Don Bourne, Eric Herness, Eric Labadie, Eric Wayne, Herb Lee, James Schoech, Jun-jang Jeng, Kumar Bhaskaran, Mike Brown, Mike Wamboldt, Nduwuisi Emuchay, Nick Butler, Peter Brittenham, Peter Sohn, Tian Chao, Valentina Popescu, Victor Chan, Kevin Denyer, Mickey Nix, and Yoichi Yoshida.
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About the author | 
| | Brent A. Miller is a member of IBM's Autonomic Computing Architecture team, where he serves as the lead architect for self-healing. He has worked for IBM for 21 years, with assignments including printer development, mobile clients, mobile software and pervasive computing. |
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