Bring the store back online
Every system behind the store went down at 09:00, minutes before a sale. Pick any component, in any order, and answer its question. Get it right and it comes back online; get it wrong and it stays down. When all ten are answered, you'll see what works for shoppers and what doesn't.
Online 0 / 10Down 0Not checked yet 10XP earned 0
Pick a component
Each component has one question, so read it carefully. Right answers bring it back online.
What users can do
- DownBrowse products and imagesNeeds DNS, CDN
- DownCheck out and payNeeds DNS, Load balancer, API gateway, App servers, Database
- DownGet order confirmation emailsNeeds App servers, Order queue, Order worker, Database
- DownSee "My orders" right after buyingNeeds DNS, Load balancer, API gateway, App servers, Read replica
What this incident covers
- DNS (name to address): DNS, HTTP, TCP in 10 Minutes
- CDN (edge caching): CDN & Edge Caching
- Load balancer (spreads traffic): Load Balancing Intro
- API gateway (auth and rate limits): Design a Rate Limiter
- App servers (checkout logic): Backpressure & Flow Control
- Cache (Redis): Caching Basics
- Database (primary): Database Indexes & Slow Queries
- Read replica (copy for reads): Replication & Sharding
- Order queue (Kafka): Queues & Pub/Sub
- Order worker (emails and charges): Idempotency & Exactly-Once Illusion