Ref: https://learn.cantrill.io/courses/1820301/lectures/41301589
R53 Latency Routing - Architecture
Diagram: https://github.com/acantril/aws-sa-associate-saac03/blob/main/1200-ROUTE53/00_LEARNINGAIDS/Route53LatencyBasedRouting-1.png
- 🔧 Multiple records with the same host name, up to one per AWS region
- Record region attached to each record
- Usually record points to region where the infrastructure is located
- Record with lowest latency to client is selected and returned in DNS queries
- AWS maintains a DB with latencies between the user’s general location and AWS regions tagged in records
- AWS uses IP lookup service to get user location
- AWS can thus deduce the latency the user has to each of the regions
- ‼️ This latency DB is NOT updated in real time!!!
- No account for local NWing issues!
- DB updated in the background, with no timeline guarantee
- 💡 The DB is still better than nothing, and can significantly help reduce latency achieve high performance. Just, don't overestimate its capabilities
- Records can have health checks
- If selected record is unhealthy, next lowest-latency record that is healthy is selected and returned to client instead
- Useful for optimizing performance and UX of global applications
