Today’s software users have come to expect new features as soon as the need for them arises. In response to this challenge, we are working to reduce the footprint of traditional software offerings and move to providing continuous delivery of new or improved capabilities. Agile practices are strengthened through application of architecture principles. Informed anticipation with just enough architecting in the context of agile release planning can provide the tools to balance of agility, innovation, and speed on the one hand, and system governance, flexibility, and planning for future needs on the other.
Agile software development methods focus on delivering observable benefits to the end user, early and often, through working software. In the Agile approach, functional user stories illustrate that particular capabilities are required. Typically these collected stories are prioritized by end-user need, but almost every story has dependencies on other stories. To optimize value to the user, teams must look ahead and anticipate future needs.
Stories also have dependencies upon the architectural elements of the system. We have defined architectural agility as the ability to identify and analyze these dependencies, and incorporate dependency awareness into a responsive development model. These additional considerations add a new dimension to the typical Agile release planning; benefits derived from the execution of architectural activities may now be allocated to either the current release or to future releases. Architectural agility offers tools that enable the software community to
adapt the agile focus on end-user stories to address the broader topic of capabilities, including quality attribute requirements
facilitate a “just-in-time” approach to building out the architectural infrastructure
optimize architectural investment decisions by analyzing uncertainty and tradeoffs between incurred cost and anticipated value
Architectural agility allows architectural development to follow a “just-in-time” model. There is no completion of exhaustive requirements and design activities and reviews to delay delivery of features. At the same time, architectural agility maintains a steady and consistent focus on continuing architectural evolution in support of emerging features.
Architectural agility requires just enough anticipation. To achieve this quality, architectural anticipation must be informed, and certain tools can help achieve this: dependency analysis, real options analysis, and technical debt management.
Developers first select capabilities to create within each iteration, then identify the architectural elements that must be implemented to support them. The term capabilities replaces user stories, reflecting a need to consider non-functional requirements such as modifiability and security, and to incorporate requirements across a broad range of stakeholders. Such dependency analysis enables the development team to prioritize and schedule work within a release.
Real option analysis examines how taking a certain action today provides an option that can be acted upon in the future. The higher the uncertainty, the more it makes sense to wait to act and defer the decisions. From this perspective the agile community has used the concept of real options in separating concerns that have immediacy and those that can possibly wait.
In addition to identifying dependencies within a given release, architectural agility also requires understanding the deliberate shortcuts taken to achieve high-priority functionality. These shortcuts must be revisited at each iteration, as they often incur technical debt —a need for extra effort later.