Architecture Field Notes
Practical architecture knowledge for DevOps engineers and developers — the decisions, trade-offs, and failure modes that only show up in production. The tacit, made explicit.
40 pages. Every one names a default, the conditions that flip it, and what it costs.
Eight areas where experience is expensive to acquire
Each page answers the same question in a different context: what does an experienced engineer actually decide here, and what are they trading away?
Foundations
Irreversible decisions, real constraints, coupling as currency, and why a boring baseline usually wins.
System Design in Practice
Monolith first, boundaries that survive reorgs, sync vs async, contracts, and designing for the duplicate request.
Data and State
Datastore choice, zero-downtime migrations, the consistency model you actually need, caching, and when CDC pays.
Delivery and CI/CD
Trunk-based development, pipelines ordered by feedback cost, progressive delivery, reproducible builds, and rollback.
Platform and Infrastructure
What Kubernetes charges, IaC that does not drift, config and secrets, tenancy models, and platform as a product.
Reliability and Operations
SLOs as a negotiating tool, observability worth paying for, backpressure, failure isolation, and useful postmortems.
Security by Design
One-hour threat models, authorisation at the resource, secrets you can rotate, supply chain, and blast radius.
Making Knowledge Explicit
ADRs people read, diagrams that age well, runbooks for 3am, design reviews, and team memory that outlives attrition.