A SOA creates a flexible architecture, which allows for ’reconfiguring’ over time. In fact, ‘agility’ has been identified as the largest single driver for a SOA. This attribute has more value when the target is a larger system that may change (following the simple assumption that larger systems are more difficult to modify than smaller ones).
A SOA approach assumes that the business benefits of lower maintenance and increased flexibility are more than offset any inefficiencies by the use of standards, components, and modularity.
However, in large scale systems, such as an enterprise IT architecture or large plant automation, there is no attractive alternative.
Services are the fundamental building blocks of a SOA. The business functionality and the corporate data are contained within the services themselves. It is important to realize that web services standards (like SOAP, WSDL, HTTP, XML, UDDI, etc.) are specific and rigorously
As your enterprise creates more services than can easily be remembered, you will need to put something in place to keep them organized. The industry standard for this is called UDDI. A UDDI registry has become a required part of all large scale SOA systems and serves as the ‘SOA System of Record’.
Beyond the basics of providing the authoritative record of the service definitions, revisions, and description, the service registry has over time taken on an additional responsibility. The registry can make a major contribution toward the governance of the services through their lifecycle.
Even with the right organization , well designed services ,the right infrastructure the right development practices and system of record things can/will still go wrong. In fact, if you do things well, you will create a system that is too sophisticated for you to easily observe it. To achieve the desired business objectives, the system must be appropriately monitored and governed at runtime using ITIL standard and recipes.