What is AWS Route 53?
Answer
Amazon Route 53 is AWS's highly available, scalable DNS (Domain Name System) and domain registrar service. Name "Route 53" comes from port 53 (DNS port). Core capabilities: (1) Domain registration: register domain names directly in Route 53; (2) DNS resolution: translates human-readable names (example.com) to IP addresses; (3) Health checking: monitor endpoints and route traffic away from unhealthy ones. Record types: A (IPv4), AAAA (IPv6), CNAME (alias to another domain — cannot be at zone apex), MX (mail), TXT (verification, SPF), NS (name servers), SOA, SRV. Route 53 Alias records: like CNAME but for AWS resources (ELB, CloudFront, S3 website, API Gateway, Beanstalk). Free DNS query charges. Works at zone apex. Routing policies: Simple: single resource; Weighted: percentage-based (10% to v2, 90% to v1 — canary testing); Latency-based: route to lowest-latency region; Failover: primary/secondary with health check; Geolocation: route based on user's location (EU → Frankfurt, US → Virginia); Geoproximity: route based on geographic distance with bias; Multivalue Answer: return multiple IPs (simple load balancing); IP-based: route based on client IP CIDR. Health checks: HTTP/HTTPS endpoint checks; calculated health checks (combine multiple); CloudWatch alarm-based. Route 53 removes unhealthy endpoints from DNS responses. Private hosted zones: DNS within a VPC — internal service discovery.