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Amazon Route 53 — DNS & Routing
Managed DNS with health checks and routing policies that turn DNS into a traffic controller.
What it is
Highly available DNS plus health checks and smart routing policies.
Routing policies (know these cold)
- Simple: one record, no logic.
- Failover: primary/secondary with health checks (DR).
- Weighted: split traffic by percentage (canary, A/B).
- Latency: send users to the lowest-latency Region.
- Geolocation / Geoproximity: route by user location.
- Multivalue: return several healthy records.
Key architectural decisions
- Pair failover routing with health checks for multi-Region DR.
- Use alias records (free, resolve to AWS resources like ALB/CloudFront/S3) over CNAMEs at the zone apex.
Gotchas & exam traps
- "Automatically move users to a healthy Region" => failover routing + health checks.
- "Lowest latency globally" => latency-based routing.
- Alias vs CNAME: only alias works at the apex (example.com).
The architect view
Route 53 is not just name resolution; it is a global traffic-steering tool. Reach for it whenever the answer involves multi-Region availability or performance.