Amazon Route 53
- What it is
- Highly available and scalable DNS web service. Named after port 53, the DNS port.
- Three jobs: domain registration, DNS routing, and health checking.
- Routing policies (know these)
- Simple — one record, one answer.
- Weighted — split traffic by percentage. Useful for A/B tests and canary deploys.
- Latency-based — send users to the Region with the lowest latency for them.
- Failover — active/passive disaster recovery based on health checks.
- Geolocation — route by where the user is, for compliance or localization.
- Geoproximity — route by geographic distance, with a bias you can shift.
- Multivalue answer — return several healthy IPs, a poor man’s load balancer.
- Key traits
- 100% availability SLA — the only AWS service with one.
- Alias records point to AWS resources (CloudFront, ELB, S3 websites) for free, and work at the zone apex where CNAMEs cannot.
- Not to be confused with
- load balancers — distribute traffic within a Region. Route 53 routes users between Regions and endpoints.