Amazon Route 53
What is Amazon Route 53?
Route53 is a managed DNS (Domain Name System) service where DNS is a collection of rules and records intended to help clients/users understand how to reach any server by its domain name.
Route 53 hosted zone is a collection of records for a specified domain that can be managed together. There are two types of zones:
● Public host zone – It determines how traffic is routed on the Internet.
● Private hosted zone – It determines how traffic is routed within VPC.
Route 53 TTL (seconds):
● It is the amount of time for which a DNS resolver creates a cache information about the records and reduces the query latency.
● Default TTL does not exist for any record type but always specifies a TTL of 60 seconds or less so that clients/users can respond quickly to changes in health status.
Route53 CNAME vs. Alias
CNAME
It points a hostname to any other hostname.
(app.mything.com -> abc.anything.com)
It works only for the non-root domains. (abcxyz.maindomain.com)
Route 53 charges for CNAME queries.
It points to any DNS record that is hosted anywhere.
Alias
It points a hostname to an AWS Resource. (app.mything.com ->abc.amazonaws.com)
It works for the root domain and non-root domain. (maindomain.com)
Route 53 doesn’t charge for Alias queries.
It points to an ELB, CloudFront distribution, Elastic Beanstalk environment, S3 bucket as a static website, or another record in the same hosted zone.
The most common records supported in Route 53 are:
● A: hostname to IPv4
● AAAA: hostname to IPv6
● CNAME: hostname to hostname
● Alias: hostname to AWS resource.
Other supported records are:
● CAA (certification authority authorization)
● MX (mail exchange record)
● NAPTR (name authority pointer record)
● NS (name server record)
● PTR (pointer record)
● SOA (start of authority record)
● SPF (sender policy framework)
● SRV (service locator)
● TXT (text record)
Route 53 Routing Policies:
Simple:
● It is used when there is a need to redirect traffic to a single resource.
● It does not support health checks.
Weighted:
● It is similar to simple, but you can specify a weight associated with resources.
● It supports health checks.
Failover:
● If the primary resource is down (based on health checks), it will route to a secondary destination.
● It supports health checks.
Geo-location:
● It routes traffic to the closest geographic location you are in.
Geo-proximity:
● It routes traffic based on the location of resources to the closest region within a geographic area.
Latency based:
● It routes traffic to the destination that has the least latency.
Multi-value answer:
● It distributes DNS responses across multiple IP addresses.
● If a web server becomes unavailable after a resolver cache a response, a user can try up to eight other IP addresses from the response to reduce downtime.
Use cases:
● When users try to register a domain with Route 53, it becomes the trustworthy DNS server for that domain and creates a public hosted zone.
● Users can have their domain registered in one AWS account and the hosted zone in another AWS account.
● For private hosted zones, the following VPC settings must be ‘true’:
○ enableDnsHostname.
○ enableDnsSupport.
● Health checks can be pointed at:
○ Endpoints (can be IP addresses or domain names.)
○ Status of other health checks.
○ Status of a CloudWatch alarm.
● Route53 as a Registrar: A domain name registrar is an organization that manages the reservation of Internet domain names.
● Domain Registrar != DNS
Price details:
● There are no contracts or any down payments for using Amazon Route 53.
● Route 53 charges annually for each domain name registered via Route 53.
● Different rates are applied for Standard Queries, Latency Based Routing Queries, Geo DNS and Geo Proximity Queries.
