Architecture diagrams to aid in systematic debugging
Per 2018-07-05 failover
The debugging of gitlab-com/migration#642 (closed) was made unnecessarily difficult due to us having to puzzle out the exact CDN setup. We should ensure up-to-date architecture diagrams exist for at least gprd, documenting the full route taken for all variations of all presented TCP services, so we can debug these things systematically when they come up.