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Building Enterprise Fitness Functions

In an evolutionary architecture, the role of the enterprise architect revolves around guidance and enterprise-wide fitness functions. Microservices architectures reflect this changing model. Because each service is operationally decoupled from the others, sharing resources isn’t a consideration. Instead, architects provide guidance around the purposeful coupling points in the architecture (such as service templates) and platform choices. Enterprise architecture typically owns this shared infrastructure function and constrains platform choices to those supported consistently enterprise wide.


At one point, the PenultimateWidgets lawyers started questioning the legal use of the open source libraries at the company. They pored over the licenses of each of the frameworks and libraries and determined that PenultimateWidgets wasn’t using anything that causes problems. But then one of the lawyers asked, “How will we know if there is a change in the licensing terms?” There was no such service.

However, once the legal team certified the current libraries, developers located the license text within the library and created a temporal fitness function that always checks for changes in that string. Thus, every time the library license changes (for any reason), the fitness function triggers that something has changed. Of course, the fitness function won’t be sophisticated enough to determine if the change is appropriate — someone will be stuck with that chore — but architects can build fitness functions that trigger directed attention rather than automating a solution.

The other new role that evolutionary architecture creates has enterprise architects defining enterprise-wide fitness functions. Enterprise architects are typically respsonsible for enterprise-wide nonfunctional requirements, such as scalability and security. Many organizations lack the ability to automatically assess how well projects perform individually and in aggregate for these characteristics. Once projects adopt fitness functions to protect parts of their architecture, enterprise architects can utilize the same mechanism to verify that enterprise-wide characteristics remain intact.

If each project uses a deployment pipeline to apply fitness functions as part of their build, enterprise architects can insert some of their own fitness functions as well. This allows each project to verify cross-cutting concerns, such as scalability, security, and other enterprise-wide concerns, on a continual basis, discovering flaws as early as possible. Just as projects in microservices share service templates to unify parts of technical architecture, enterprise architects can use deployment pipelines to drive consistent testing across projects.

Case Study: PenultimateWidgets as a Platform

Business at PenultimateWidgets is going so well they have decided to sell part of their platform to other sellers of things like widgets. Part of the appeal of the PenultimateWidgets platform is its proven scalability, resiliency, performance, and other assets. However, their architects don’t want to sell the platform only to start hearing stories of failures because users extend it in damaging ways.

To help preserve the important characteristics of the platform, the PenultimateWidgets architects provide a deployment pipeline along with the platform with built-in fitness functions around important dimensions. To remain certified, users of the platform must preserve the existing fitness functions and (hopefully) add their own as they extend the platform.

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