Concepts
Architectural designs in an agile environment are an essential component of software development. The Certified Scrum Developers (CSD) exam requires an understanding of key principles of architecture within this context. This post will discuss three significant principles: Simplicity, Evolutionary Design, and High Quality.
1. Simplicity
The principle of simplicity, also known as YAGNI (You Aren’t Gonna Need It), is about avoiding unnecessary complexity. The Agile Manifesto encourages focusing on developing software that satisfies the customer’s immediate needs rather than predicting and building for potential future needs.
For example, if you are creating software to manage a library, you might initially focus on basic functionalities such as cataloguing books and managing check-outs. Rather than investing time and resources into designing aspects such as an advanced book recommendation system, which the library may never need, the agile methodology encourages beginning with the most simple version of the software to meet the user’s immediate needs.
| Traditional Approach | Agile Approach |
|---|---|
| Complex structures | Simple designs |
| Emphasis on future needs | Focus on current needs |
| Can result in wasted development time | Time is focused on priority features |
2. Evolutionary Design
Evolutionary design embraces the principle that the design of the system evolves over time. As opposed to Big-Design-Up-Front (BDUF) where all the design is completed up front, in the evolutionary design, the system is developed incrementally through continuous refactoring and regular iteration.
Consider an online shopping application. In a BDUF approach, elements like payment gateways, order tracking, customer reviews etc., would all be designed and built up front. By contrast, in an evolutionary design, a basic system might initially only support purchases with credit cards. Future iterations would then add support for other payment methods or other features like order tracking.
| Traditional Approach | Agile Approach |
|---|---|
| All aspects designed upfront | Design evolves over time |
| Rigid, less room for change | Flexible to changes |
| Challenging to accommodate late changes | Changes can be incorporated naturally |
3. High Quality
The agile principle of high quality mandates that every piece of the architecture must meet high-quality standards to avoid technical debt. Insisting on quality doesn’t mean perfection, but rather the top priority is to deliver a working product of significant quality at every iteration.
Suppose you’re developing a health tracking app. Even the first version that only tracks the steps of users should be developed with quality in mind. Without high quality, it could lose the synchronization with pedometer data or miscount the steps, leading to unhappy users.
| Traditional Approach | Agile Approach |
|---|---|
| Quality can be compromised for features | Quality is uncompromisable |
| Tendency for more bugs and fixes later | Less technical debt, fewer bugs |
Understanding and implementing these three principles helps to ensure we are creating a software architecture that is not only robust and adaptive to change but also meets the needs of the customer efficiently and effectively – a fundamental objective in the CSD exam.
Answer the Questions in Comment Section
True or False: In an agile environment, the architecture must evolve through multiple iterations throughout the project’s lifecycle.
- True
Answer: True.
Explanation: Agile architecture allows for adaptability and change through its iterative approach, which enables continuous integration and improved feedback loop.
The principle of “enough modeling” in agile architecture suggests that:
- a) Every detail of the architecture should be meticulously modeled.
- b) Modeling efforts should be minimized.
- c) The architecture should be modeled only to a sufficient extent to fulfill the project’s current needs.
- d) The architecture should be modeled without considering the project’s current needs.
Answer: c) The architecture should be modeled only to a sufficient extent to fulfill the project’s current needs.
Explanation: The principle of enough modeling asserts that architecture should be modeled as much as required to meet the current needs, rather than over-modeling or under-modeling it.
True or False: The architecture in an agile environment should be very complex to include all possible future developments.
- False
Answer: False.
Explanation: Agile architecture advocates simplicity. It should be as simple as possible and only include functionalities that the product currently requires. The architecture can evolve over iterations as more functionalities are needed.
Which three principles are commonly associated with agile architecture?
- a) Enough modeling
- b) Simplicity
- c) Evolving architecture
- d) Static architecture
Answer: a) Enough modeling, b) Simplicity, c) Evolving architecture.
Explanation: Enough modeling, simplicity, and evolving architecture are three principles associated with agile architecture, asking for the right amount of modeling, simplicity in design, and an architecture that evolves with project needs.
An agile architecture is rigid and difficult to change.
- False
Answer: False.
Explanation: The flexibility to accommodate changing requirements is one of the key principles of architecture in an agile environment.
True or False: One of the principles of agile architecture is to have a final and complete architectural design before starting with the development.
- False
Answer: False.
Explanation: Agile architecture evolves over time and does not require a complete architectural design from the start.
The principle of simplicity in agile architecture implies:
- a) The design should be as complex as possible.
- b) Extra features should be added unnecessarily.
- c) The design should be as simple as possible.
- d) Irrelevant details should be included.
Answer: c) The design should be as simple as possible.
Explanation: The principle of simplicity in agile architecture advocates for a simple and uncomplicated design that meets the current needs of the project.
True or False: According to enough modeling, extra details should be added regardless of their need in the current project.
- False
Answer: False.
Explanation: The principle of enough modeling suggests that only the necessary amount of modeling needed to meet the project’s current needs should be done.
The evolving architecture principle:
- a) Discourages change.
- b) Allows changes only in the early stages.
- c) Encourages changes throughout the development process.
- d) None of the above.
Answer: c) Encourages changes throughout the development process.
Explanation: The principle of evolving architecture allows for changes and evolution throughout the development process, making it suitable for changing requirements and environments.
Agile architecture does not require any architectural modeling.
- False
Answer: False.
Explanation: While agile architecture advocates simplicity and evolution, it still requires a sufficient amount of architectural modeling, also known as “enough modeling”.
I think one of the core principles of architecture in an agile environment is ‘Embrace Change.’ How do others incorporate this into their daily routines?
Absolutely! We run continuous integration and frequent refactorings, which really help to embrace change in my team.
I agree, ‘Embrace Change’ is critical. In my team, we use small, incremental updates to make big changes less daunting.
Thanks for the insightful post!
Another important principle is ‘Build for Today but Plan for Tomorrow.’ How do you balance immediate needs with long-term goals?
We use architectural spikes to explore long-term solutions without impacting the current sprint.
My team uses technical debt tracking tools to ensure we address short-term needs without compromising long-term goals.
Appreciate the blog post, very helpful!
I find ‘YAGNI (You Aren’t Gonna Need It)’ to be a critical principle in agile architecture. Do others feel the same?
Yes, ‘YAGNI’ helps us avoid over-engineering and focus on immediate needs.
Totally agree! ‘YAGNI’ is a guiding principle in our development process to keep things lean.
Great insights, thank you!
Not sure if ‘Embrace Change’ is always feasible. We’ve struggled with it due to legacy systems.
Legacy systems can be a challenge. Have you tried adopting a phased approach to modernization?
It’s tough but possible. We started with small, non-critical services and gradually modernized.
This is super useful, thanks!