The Art of Agile Development, 2nd Edition

Evolutionary System Architecture

AUDIENCE

Programmers, Operations

We build our infrastructure for what we need today, without sacrificing tomorrow.

Simplicity is at the heart of Agile, as discussed in “SIMPLICITY”. It’s particularly apparent in the way fluent Delivering teams approach evolutionary design: they start with the simplest possible design, layer on more capabilities using incremental design, and constantly refine and improve their code using reflective design.

What about your system architecture? By system architecture, I mean the components that make up your deployed system. The applications and services built by your team and the way they interact. Your network gateways and load balancers. Even third-party services. What about them? Can you start simple and evolve from there?

That’s evolutionary system architecture, and I’ve seen it work on small systems. But system architectures are slow to evolve, so there isn’t the same depth of industry experience behind evolutionary system architecture that there is behind evolutionary design. Use your own judgment about how and when it should be applied.

NOTE

I make a distinction between system architecture and application architecture. Application architecture is the design of your code, including decisions about how to call other components in your system. It’s discussed in “Application architecture”. This practice discusses system architecture: decisions about which components to create and use, and the high-level relationships ...