Infrastructure Map
Maintain an operator-readable map of boundaries, dependencies, and control points before scaling or incidents amplify blast radius.
This page tracks dependency truth and helps teams choose safe changes through explicit trust and data-flow boundaries.
Engineering rationale
Infrastructure maps are most valuable when they represent ownership, control, and communication boundaries together, not only network topology.
The focus here is practical: every edge should answer “what breaks if this changes” and “who has authority to change it.”
Architecture tradeoffs
- Static maps are low maintenance but stale quickly; living maps require more process but stay usable.
- Service abstraction simplifies operations, but hides underlying capacity coupling and data-path assumptions.
- Single-source mapping improves consistency, while decentralized ownership improves speed at small scale.
Reliability mindset
- Prioritize high-impact edges and run dependency checks for those before every planned change.
- Track map freshness with review cadence, ownership tags, and stale-edge warnings.
- Model cascades in advance so blast radius estimates are realistic under partial failures.
- Record fallback paths and failover assumptions alongside dependency relationships.
Lessons learned
- Most unexpected outages follow an unrecorded dependency crossing between teams.
- Maps that are only visual assets but not operational workflows fail to prevent change risk.
- Boundary docs should include control points, not just transport or DNS locations.
Practical checklist
- List critical service dependencies and assign one accountable owner per edge.
- Record fallback dependencies and expected recovery behavior for each high-risk path.
- Mark any undocumented coupling in an exception register.
- Review dependency map during architecture changes and pre-maintenance planning.
- Use map-backed change requests to force blast-radius discussion before execution.