Building evolvable architectures

Many of the concepts we discussed aren't new ideas, but rather viewed through a new lens. For example, testing has existed for years, but not with the fitness function emphasis on architectural verification. Continuous Delivery defined the idea of deployment pipelines. Evolutionary architecture shows architects the real utility of that capability.

Many organizations pursue Continuous Delivery practices as a way to increase engineering efficiency for software development, a worthy goal in itself. However, we're taking the next step, using those capabilities to create something more sophisticated — architectures that evolve with the real world.

Mechanics

Architects can operationalize these techniques for building an evolutionary architecture in three steps:

1. Identify dimensions affected by evolution
2. Define fitness function(s) for each dimension
3. Use deployment pipelines to automate fitness functions

[...] Software suffers from the unknow unknows problem: developers cannot anticipate everything. [...] 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.

Neal Ford, Rebecca Parsons & Patrick Kua, "Building Evolvable Architectures", in Building Evolutionary Architectures: Support Constant Change, 95-96.