Use Deployment Pipelines to Automate Fitness Functions
Lastly, architects must encourage incremental change on the project, defining stages in a deployment pipeline to apply fitness functions and managing deployment practices like machine provisioning, testing, and other DevOps concerns. Incremental change is the engine of evolutionary architecture, allowing aggressive verification of fitness functions via deployment pipelines and a high degree of automation to make mundane tasks like deployment invisible. Cycle time is the Continuous Delivery measure of engineering efficiency. Part of the responsibility of developers on projects that support evolutionary architecture is to maintain good cycle time. Cycle time is an important aspect of incremental change because many other metrics derive from it. For example, the velocity of new generations appearing in an architecture is proportional to its cycle time. In other words, if a project’s cycle time lengthens, it slows down how fast the project can deliver new generations, which affects evolvability.
While the identification of dimensions and fitness functions occurs at the beginning of a new project, it is also an ongoing activity for both new and existing projects. Software suffers from the unknown unknowns problem: developers cannot anticipate everything. During construction, some part of the architecture often shows troubling signs, and building fitness functions can prevent this dysfunction from growing. While some fitness functions will naturally come to light at the beginning of a project, many won’t reveal themselves until an architectural stress point appears. Architects must vigilantly watch for situations where nonfunctional requirements break and retrofit the architecture with fitness functions to prevent future problems.