Module 5 of 5
Worked designs
Four complete designs, each argued from its invariants: a rate limiter, a credential broker, a tamper-evident audit log, and a multi-tenant inference gateway.
Every earlier module took one idea and looked at it closely: invariants, partial failure, races, consistency, error budgets. This module puts the ideas together. Each lesson takes one system and walks the same route: requirements, the invariants that must hold, a capacity estimate with real arithmetic, the design, how it fails, a security review, and what changes when load grows tenfold.
The four systems are ones security and platform teams actually build and operate: a rate limiter, a broker that issues short-lived credentials, an audit log that shows when it has been altered, and a gateway that shares model capacity among tenants. By the end you should be able to defend a design the same way, starting from what it promises and checking every component against those promises, not from a diagram of boxes.
Lessons
- 5.aA rate limiterHow do you limit request rates per tenant, across many servers, without the limiter becoming the outage?21 min
- 5.bA credential brokerHow do you design a service that issues short-lived scoped credentials without making it a single point of failure or a single point of compromise?23 min
- 5.cA tamper-evident audit logHow do you build an audit log whose history cannot be rewritten without someone noticing?21 min
- 5.dA multi-tenant inference gatewayHow do you share model capacity among many tenants so that a noisy neighbor stays contained and no tenant sees another tenant's data?20 min