Architecture & System Design — Phase 7 Field Guide
Source-informed learning material inspected 11 October 2026. Repository files demonstrate code/configuration, not live uptime, security accreditation, load-test results or currently provisioned cloud resources. Proposals are explicitly marked.
Architecture starts with a user need and a constraint—not a cloud service. These eleven lessons build a repeatable method for discussing system boundaries, failure, identity, state, costs and evidence.
Learning sequence
| Lesson | Decision you should be able to defend |
|---|---|
| 01 — Requirements and quality attributes | What are we optimizing for, and how do we measure it? |
| 02 — Context, containers, trust boundaries | What crosses each boundary? |
| 03 — State, events and idempotency | What prevents duplicate work and inconsistent writes? |
| 04 — Reliability and capacity | What fails, how do we detect it, and how do we recover? |
| 05 — Security architecture | Which identity can do exactly what? |
| 06 — AWS and Azure decisions | What is implemented versus planned in each cloud? |
| 07 — Internal Developer Platforms | Where do templates, delivery and runtime authority differ? |
| 08 — Multi-tenant SaaS | How are tenants isolated at every layer? |
| 09 — AI and operational control planes | Why must evidence and approval be separate from actions? |
| 10 — ADRs and architecture reviews | How do we record alternatives and consequences? |
| 11 — Capstone and interview exercises | Can we review an end-to-end design with explicit trade-offs? |
Source map
- OpsPilot: multi-tenant repository contract, isolated PostgreSQL tests and approval idempotency.
- CloudOps: deterministic Decision Trace and approval gate.
- PlatformPilot: Kubernetes API and Prometheus access, application RBAC.
- Backstage portal: scaffolder template with repository publish and catalog registration.
- Argo CD GitOps: reconciled NGINX demo and isolated AppProject.
- Terraform EKS: reusable infrastructure and plan-only AWS CI.
- PropertyOps: deployed Azure components and prepared-but-unused Container Apps VNet subnet.
- RAG Ops Assistant: read-only retrieval tool, model boundary and no-evidence guard.
Evidence convention
Implemented means a source artifact is present; tested names the actual test scope; deployed evidence is historical unless freshly checked; proposed means a design exercise. Never convert a diagram into a claim about production state.
Safe exercises: inspect repository code, sketch boundaries, and complete checklists. No cloud writes or production remediation are required.
Return to Chapter 11 or the project index.