Amazon Route 53

Amazon Route 53 is a managed DNS (Domain Name System) service of Amazon Web Services that provides the collection of rules and records clients use to find a server by its domain name. It is a globally specified service rather than a regional one, and it works closely with Amazon CloudFront, Elastic Load Balancing (ELB), and Amazon VPC to route and register traffic.

It is a authoritative DNS service from Amazon Web Services

Key points

• A hosted zone is a collection of records for a specified domain that can be managed together; there are two types:
  • Public Hosted Zone — determines how traffic is routed on the Internet.
  • Private Hosted Zone — determines how traffic is routed within a VPC.
• Most common record types:
  • A — hostname to IPv4.
  • AAAA — hostname to IPv6.
  • CNAME — hostname to hostname.
  • Alias — hostname to AWS resource.
• Route 53 CNAME vs Route 53 Alias:
  • CNAME points a hostname to any other hostname (e.g. app.mything.com -> abc.anything.com); Alias points a hostname to an AWS resource (e.g. app.mything.com -> abc.amazonaws.com).
  • CNAME works only for non-root domains (abcxyz.maindomain.com); Alias works for both the root domain and non-root domains (maindomain.com).
  • CNAME charges for queries; Alias does not charge for queries.
  • CNAME points to any DNS record hosted anywhere; Alias points to an ELB, CloudFront distribution, Elastic Beanstalk environment, S3 bucket configured as a static website, or another record in the same hosted zone.
• Routing policies:
  • Simple — redirects traffic to a single resource; does not support health checks.
  • Weighted — like Simple, but a weight is specified per resource; supports health checks; useful for percentage-based traffic splits such as A/B testing or a gradual rollout.
  • Failover — active-passive routing to a secondary destination if the primary resource is down, based on health checks; supports health checks.
  • Geo-location — routes traffic based on the geographic location of the user making the request, not the resource; used for content restriction or compliance rather than for performance.
  • Geo-proximity — routes traffic based on the geographic location of resources (and optionally users), with the ability to shift more traffic toward a resource using a bias value; requires Route 53 Traffic Flow.
  • Latency based — routes traffic to the Region with the least latency for the user.
  • IP-based — routes traffic based on the CIDR block that the querying client’s IP address belongs to, using customer-defined CIDR collections; used to tune performance or network transit costs based on knowledge of the client base.
  • Multi-value answer — returns up to eight healthy records selected at random, combining simple DNS with health checks; not a substitute for a load balancer.
• Route 53 is a global service, specified globally rather than regionally, and can register DNS domain names.
• Can monitor EC2 instances by pinging their DNS addresses via health checks.

Pricing

• Charges apply for CNAME queries; no charge for Alias queries.

Sources

• Choosing a routing policy