Route 53

Question 1

R53 Private Hosted Zone

Answer 1

Associated with VPCs

Accessible only within a VPC it is hosted in

Question 2

Split View Hosted Zones

Answer 2

Public and Pvt hosted zones
records in Pvt zone could be superset of records in Public Zone
This allows Public Zone to only see a subset of the records
This is a way to “partition” who sees what depending on whether they are accessing the domain from the internet or inside a VPC

Question 3

Split View Hosted Zones

Answer 3

Public and Pvt hosted zones
Records in Pvt zone could be superset of records in Public Zone
This allows Public Zone to only see a subset of the records
This is a way to “partition” who sees what depending on whether they are accessing the domain from the internet or inside a VPC

Question 4

CNAME vs ALIAS

Answer 4

When to use one vs the other
“A” record maps NAME to an IP address
CNAME makes a NAME to another NAME
www.catagram.io => catagram.io
CNAME is invalid for the apex: catagram.io
Pointing CNAM (catagram.io) => ELB is invalid

This is fixed by ALIAS
Alias maps a NAME to an AWS Resource
Can be used for apex or normal records

Question 5

Simple Routing

Answer 5

Starts with Hosted Zone
Create one record per name eg: www = A record type
Each record can have multiple values (1.2.3.3, 1.2.3.4, 1.2.3.5 etc)
All values are returned in random order
Client chooses and uses 1 value to connect
Does not support health check - all values are returned when queried
Simple to implement and manage

Use when you want to route requests towards one service like Web server

Question 6

Healthcheck Feature

Answer 6

• Separate from, but are used by records
• Fleet of health checkers globally
• Do not block them thinking they are bots
• Checks occur ever 30s by default
• Can be TCP checks, HTTP/HTTPS

Types of checks:
Endpoint checks
Cloudwatch Alarm
Calculated Checks

Question 7

Multivalue Routing

Answer 7

Multiple values are returned
Client chooses one and uses it
Upto 8 healthy records are returned, if more exist 8 are randomly selected
Not a substitute for load balancer

Question 8

Weighted Routing

Answer 8

Simple form of LB or for Testing new version of software
Weight for each record can be specified eg: 40, 40, 20 for 3 records
Each record gets returned based on its weight - 40%, 40%, and 20% of the time
If record weight is 0 it is not returned

Question 9

Latency Routing

Answer 9

When you are trying to optimize for performance and UX

“Record region” can be specified for each record, so depending on user’s IP the IP with least latency is returned

Question 10

Geolocation Routing

Answer 10

Similar to latency, but instead of latency location of user is taken into account
Each record is tagged with the geolocation
When a user makes a request, IP check verifies the user location and returns relevant records matching the user location

State > Country > Continent > default

Used for restricting content

This is not about closest record, GEOLOCATION returns relevant records based on your location

If you are in US and there is a record tagged as US you get that

Question 11

Geoproximity Routing

Answer 11

Aims to provide records as close to your customers as possible
Aims to calculate the distance between record and customer
Define rules for each resource
1 in USA, UK and AUS
LAT and LONG are assigned to the resource or be tagged with an AWS Region
R53 knows the location of the resources and the client’s location
Bias can be used to influence the proximity and override the closest one