Route 53 Cheat Sheet

• A highly available, scalable, fully managed and authorative DNS.

• A domain registrar.
• Only AWS service which provides 100% availability SLA.
• 53=DNS port

Route 53 Records:

• A – maps hostname to IPV4.
• AAAA – maps hostname to IPV4.
• CNAME– maps hostname to another hostname. Target is domain name and it must be A or AAAA record.
• NS– name server for hosted zones

Public hosted zone: how to route traffic over internet.

Private hosted Zone: how to route traffic withing one or more VPC without intent.

Route 53- Record TTL: 1) Hight TTL: 24 hrs and outdated content. 2) low TTL: 60 sec, easy to change. Except for alias record, TTL is mandatory for each DNS records.

Alias Record: points hostname to AWS resources. Free of charge, native health checks, works for both root and non-root domains, an extension to DNS functionality. Automatically recognizes changes in the resource IP address. It is always A or AAAA record and TTL can’t be set. Alias records targets are

1. ELB
2. Cloudfront
3. API Gateway
4. S3 websites
5. Elastic Beanstalk Environment
6. VPC Interface endpoints
7. Global Accelerator

Route 53 records in same hosted zone

Route 53 Routing policies:

1. Routing Policies – Simple: No Health Check.
2. Routing Policies – Weighted: Health Check, can route the request based on % defined. Like 70% to region A, 30% to region B.
3. Routing Policies – Latency: Health Check, user close to Mumbai will be connect to Mumbai region rather than connecting to Paris region.
4. Routing Policies – Failover: Health Check, Disaster Recovery. Active-passive.
5. Routing Policies – Geolocation: This routing is based on user location. Should create default record incase no match is found on location. Can be associated with health checks
6. Routing Policies – Geoproximity: Must use route 53 traffic flow. Route traffic to your resources based on geographics locations of user and resources. Ability to shift more traffic to resource based on defined bias.
7. Routing Policies – multivalue: Routing traffic to multiple resources. Can be associated with health check. Up to 8 healthy records are returned for each multi value query.

Route 53 – Health Check (public): are only for public resources and it is integrated with clout watch metrics. About 15 global health checker. Can be setup to pass or fail based on text in first 5120 bytes of resource.

Calculated Health checks: combine the result of multiple health check into a single health check. OR, AND and NOT. Cab monitor up to 256 child health checks.