The Decision Engineering Method¶
Start with a business or platform problem. Compare viable architectures, implement the smallest useful slice, and use evidence to review the decision.
1. Frame the problem¶
Identify the stakeholder, the outcome they need, the current pain, and the consequence of leaving it unresolved. Separate observed facts from assumptions and state what is outside the problem.
2. Define success and constraints¶
Turn the outcome into measurable criteria. Capture latency, availability, recovery, data quality, security, skills, delivery time, and budget constraints. Record unknowns that could change the decision.
3. Model the workload¶
Describe producers, consumers, volume, velocity, formats, sensitivity, access patterns, ownership, growth, and likely failure modes.
4. Create viable options¶
Produce at least two credible architectures. Show data flow, persistent state, boundaries, ownership, and failure paths. Each option must optimize for something relevant to the scenario.
5. Evaluate trade-offs¶
Compare the options using decision drivers derived from the problem. Consider cost, reliability, operability, security, delivery speed, team fit, and reversibility. Do not hide uncertainty behind an arbitrary score.
6. Record the decision¶
Write an Architecture Decision Record that explains the selected option, rejected alternatives, decisive reasons, risks, assumptions, and conditions that would invalidate the choice.
7. Build the smallest useful slice¶
Use Terraform to implement only enough of the architecture to test the important claims. Keep it low-cost, observable, synthetic, and completely removable.
8. Validate the decision¶
Run the happy path, inject at least one controlled failure, inspect the relevant engineering signals, and connect the evidence to the original business outcome.
9. Review and evolve¶
Compare expected and observed results. Keep, modify, or reject the architecture. Document the production gap and define the next decision instead of creating an uncontrolled feature backlog.
What the engineer produces¶
- A business brief and measurable success criteria
- A workload model
- Viable architecture options
- A decision matrix and Architecture Decision Record
- A reproducible Terraform thin slice
- Validation, failure, recovery, and cost evidence
- A production-gap assessment
- A concise explanation suitable for a design review
Scope¶
The goal is architecture judgement through decisions that can be explained, implemented, tested and revised. Each lab identifies its assumptions, constraints and remaining production gaps.