Route 53

Every architecture needs a way to translate domain names to IP addresses, and increasingly, to make smart decisions about which IP to hand back — based on health, latency, or geography. Amazon Route 53 solves both: it’s a highly available, scalable DNS service, and also a traffic-routing / DNS failover engine with multiple routing policies beyond simple A records.

• Route 53 is a global service — hosted zones and records aren’t tied to any single region.
• A Public Hosted Zone manages DNS for a domain on the public internet; a Private Hosted Zone resolves custom names only within associated VPCs.
• Health checks can monitor endpoints in any region and drive routing decisions (e.g. failover to a healthy region) regardless of where Route 53 itself “runs.”

graph TD
R53["Route 53 Hosted Zone"] -->|"Weighted"| A1["Endpoint A (70%)"]
R53 -->|"Weighted"| A2["Endpoint B (30%)"]
R53 -.->|"Failover"| A3["Standby Endpoint"]
R53 -->|"health check"| A1

Route 53 bills a monthly charge per hosted zone, plus a small per-million-queries charge, plus per-health-check charges. It’s inexpensive relative to most other networking services, but scales with how many zones and health checks a large architecture accumulates.

• Know the routing policies cold: Simple (one record, no logic), Weighted (percentage split, e.g. canary deploys), Latency-based (routes to the region with lowest latency for the user), Failover (active-passive with health checks), Geolocation (route by user’s location, e.g. compliance), Geoproximity (route by location with bias adjustment, needs Route 53 traffic flow), Multi-value answer (return several healthy IPs, lightweight load balancing).
• Alias records are a Route 53-specific record type that let you point a domain’s apex/root (example.com, not just www.example.com) at AWS resources like an ALB or CloudFront distribution — and unlike a CNAME, alias record lookups are free.
• Health checks can monitor an endpoint, another health check (calculated health checks), or CloudWatch alarms, and are the trigger behind Failover routing.
• Route 53 Resolver, Private Hosted Zones, and the built-in VPC DNS resolver (covered separately) are related but distinct pieces of the same overall DNS story.