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Route 53 ​

  • TTL
  • CNAME vs Alias
  • Health Checks
  • Routing Policies
    • Simple
    • Weighted
    • Latency
    • Failover
    • Geolocation
    • Multi Value
  • 3rd party domains integration

AWS Route 53 Overview ​

  • Route53 is a Managed DNS (Domain Name System)

  • DNS is a collection of rules and records which helps clients understand how to reach a server through URLs.

  • In AWS, the most common records are:

    • A: hostname to IPv4
    • AAAA: hostname to IPv6
    • CNAME: hostname to hostname
    • Alias: hostname to AWS resource.

  • Route53 can use:

    • public domain names you own (or buy) application1.mypublicdomain.com
    • private domain names that can be resolved by your instances in your VPCs. application1.company.internal

  • Route53 has advanced features such as:

    • Load balancing (through DNS - also called client load balancing)
    • Health checks (although limited...)
    • Routing policy: simple, failover, geolocation, latency, weighted, multi value

  • You pay $0.50 per month per hosted zone

DNS Records TTL (Time to Live) ​

  • High TTL: (e.g. 24hr)
    • Less traffic on DNS
    • Possibly outdated records
  • Low TTL: (e.g 60 s)
    • More traffic on DNS
    • Records are outdated for less time
    • Easy to change records
    • TTL is mandatory for each DNS record

CNAME vs Alias ​

  • AWS Resources (Load Balancer, CloudFront...) expose an AWS hostname: lb1-1234.us-east-2.elb.amazonaws.com and you want myapp.mydomain.com
  • CNAME:
    • Points a hostname to any other hostname. (app.mydomain.com => blabla.anything.com)
    • ONLY FOR NON ROOT DOMAIN (aka. something.mydomain.com)
  • Alias:
    • Points a hostname to an AWS Resource (app.mydomain.com => blabla.amazonaws.com)
    • Works for ROOT DOMAIN and NON ROOT DOMAIN (aka mydomain.com)
    • Free of charge
    • Native health check

Simple Routing Policy ​

  • Maps a hostname to another hostname
  • Use when you need to redirect to a single resource
  • You can't attach health checks to simple routing policy
  • If multiple values are returned, a random one is chosen by the client

Weighted Routing Policy ​

  • Control the % of the requests that go to specific endpoint
  • Helpful to test 1% of traffic on new app version for example
  • Helpful to split traffic between two regions
  • Can be associated with Health Checks

Latency Routing Policy ​

  • Redirect to the server that has the least latency close to us
  • Super helpful when latency of users is a priority
  • Latency is evaluated in terms of user to designated AWS Region
  • Germany may be directed to the US (if that's the lowest latency)

Health Checks ​

  • Have X health checks failed => unhealthy (default 3)
  • After X health checks passed => health (default 3)
  • Default Health Check Interval: 30s (can set to 10s - higher cost)
  • About 15 health checkers will check the endpoint health
  • => one request every 2 seconds on average
  • Can have HTTP, TCP and HTTPS health checks (no SSL verification)
  • Possibility of integrating the health check with CloudWatch
  • Health checks can be linked to Route53 DNS queries!

Failover Routing Policy ​

Geo Location Routing Policy ​

  • Different from Latency based!
  • This is routing based on user location
  • Here we specify: traffic from the UK should go to this specific IP
  • Should create a "default" policy (in case there's no match on location)

Geoproximity Routing Policy ​

  • Route traffic to your resources based on the geographic location of users and resources
  • Ability to shift more traffic to resources based on the defined bias
  • To change the size of the geographic region, specify bias values:
    • To expand (1 to 99) - more traffic to the resource
    • To shrink (-1 to -99) - less traffic to the resource
  • Resources can be:
    • AWS resources (specify AWS region)
    • Non-AWS resources (specify Latitude and Longitude)
  • You must use Route 53 Traffic Flow (advanced) to use this feature

Multi Value Routing Policy ​

  • Use when routing traffic to multiple resources
  • Want to associate a Route 53 health checks with records
  • Up to 8 healthy records are returned for each Multi Value query
  • Multi Value is not a substitute for having an ELB

Route53 as a Registrar ​

  • A domain name registrar is an organization that manages the reservation of Internet domain names
  • Famous names:
    • GoDaddy
    • Google Domains
    • Etc...
  • And also... Route53 (e.g. AWS)!
  • Domain Registrar != DNS

3rd Party Registrar with AWS Route 53 ​

  • If you buy your domain on 3rd party website, you can still use Route53.
    1. Create a Hosted Zone in Route 53
    2. Update NS Records on 3rd party website to use Route 53 name servers
  • Domain Registrar != DNS
  • (But each domain registrar usually comes with some DNS features)