Web Services Challenges

The specific Web services challenges facing companies deploying projects such as General Products' can be classified into five main categories:

• Managing service lifecycles (minimizing the impact of change)
• Web Services and Service Level Agreements: Definition and Enforcement
• Web Services Control: Taking Control of Your Network
• Web Services Provisioning to meet specific consumer needs
• Web Services Cost: Actional Provides Solution to Reduce Costs

While every project will not necessarily need to address every one of these issues, even the simplest of projects will face many of these same Web services problems. Let's take a look at each of these problem categories to understand its potential impact on the General Products project.

Managing Service Lifecycles

Services, like applications, have lifecycles. The SOA lifecycle typically consists of service creation, service deployment, service upgrades (sometimes including rollbacks) and service retirement. We've seen how easily services can be created and deployed when Web services are used; however, there are significant issues in upgrading, rolling back and retiring services from usage once they are deployed. Managing these lifecycle events and their impact on operations is a complex and potentially costly operation precisely because Web services consumers, by their very nature, are loosely coupled to the provided services. Consequently, when a service changes, organizations must first identify all of the consumers of that service and coordinate the simultaneous upgrading of all consumer applications. This process can be extremely costly, time consuming and complex.

For example, let's say that General Products needs to upgrade its SAP system and add new functionality to the Inventory Record Web service. The .NET platform, the J2EE application server, and the warehouse system all consume this service. Many downstream services also depend on this service. Beyond the cost of upgrading the service logic itself, the General Products project team must coordinate upgrading the three consuming applications, recode those applications, and schedule downtime and upgrade processes between the applications and consumers of downstream services. Even in this simple example, the ability to roll out a logic upgrade is both complex and expensive.

Web Services and Service Level Agreements: Definition and Enforcement

By definition, building applications using Web services entails the composition and assembly of services that are loosely coupled and provided by other systems. It is critical to understand the performance characteristics of the services that will comprise any given application.

In addition the developer of a given application may be held to provide specific levels of performance on services that he delivers to others. Therefore, Web service projects must include the ability to define, measure and monitor specific performance characteristics of the services consumed and provided by the project. These sets of performance characteristics are often referred to as service-level agreements (SLAs) and can be either explicitly or implicitly defined and managed.

Further, project administrators must be able to quickly spot variations in performance so they can act to prevent failure and minimize the impact of failure. Overall, the costs of failing to actively manage performance can range from lost revenue and productivity to actual hard dollar penalties from failing to meet explicit SLA targets.

In the General Products example, the Web services team has promised certain levels of response time to the team that manages the customer service and self-service portals, specifically around the response time and availability of the Inventory Availability, Available-to-Promise, and Enter Order services. Failure to meet these targets results in an escalating set of charge backs to the IT group, based on estimated productivity and revenue loss.

The Cost Developing an Alerting, Monitoring and Reporting Capability

The mission-critical nature of the service level agreements requires a comprehensive system of alerting, monitoring and reporting. Developing this capability adds time and cost to the project, delaying its rollout and time to value. In addition, because this capability is custom built, it is expensive to maintain, change and deploy as the needs of the project change, adding still more life cycle costs to the project.

For More Information

To learn more about managing Web services challenges, including service lifecycles, view the webinar, Optimizing the SOA Lifecycle from Design Time to Runtime with Comprehensive Governance