Route 53

Question 1

What is Route 53?

Answer 1

A highly available, scalable, fully managed DNS

Question 2

What does a Route 53 record do and what are the 5 things it contains?

Answer 2

It defines how traffic should be routed for a domain and contains
1. Domain/subdomain name
2. Record type (A, AAAA, CNAME, NS)
3. Value (IP address)
4. Routing policy
5. TTL

Question 3

What does an A record map?

Answer 3

Hostname to IPv4

Question 4

What does an AAAA record map?

Answer 4

Hostname to IPv6

Question 5

What does a CNAME record map?

Answer 5

Hostname to another hostname

Question 6

What does a NS record map?

Answer 6

Name servers for a hosted zone

Question 7

What are the two types of hosted zones?

Answer 7

1. Public - Can be resolved on the internet
2. Private - Can only be resolved within one or more VPCs

Question 8

What does a record TTL do?

Answer 8

Defines a period of time for a client to cache a DNS record before it expires

Question 9

When would you use an Alias over a CNAME?

Answer 9

Alias’s work for root domains and non root domains whereas CNAME records only work for non root domains. They are also free of charge and have a native health check

Question 10

Can you set a TTL for A and AAAA records?

Answer 10

No, Alias record TTL’s are set automatically by Route 53

Question 11

Is it possible to set an Alias record for an EC2 DNS name?

Answer 11

No

Question 12

List the 8 different routing policy types Route 53 supports.

Answer 12

1. Simple
2. Weighted
3. Failover
4. Latency
5. Geolocation
6. Multi-value answer
7. Geoproximity
8. IP-based

Question 13

When should you use a simple route policy?

Answer 13

Typically used to route traffic to a single resource (although multiple values can be return and one will be chosen at random by the client). Cannot be associated with a health check

Question 14

When should you use a weighted route policy?

Answer 14

When you need to control the % of requests that go to each specific resource. Note, the % does not need to add to 100%. Traffic (%) = [weight of record]/[sum of all record weights]. Note, if all records have a weight of 0, traffic will be distributed evenly.

Question 15

When should you use a latency route policy?

Answer 15

Directs based on latency between users and AWS regions. Records are associated with a region and the one with the lowest latency for the user will be used.

Question 16

What are the 3 things a health check can be based on?

Answer 16

1. Monitoring a specific endpoint
2. Monitoring other health checks
3. Monitoring CloudWatch alarms

Question 17

When should you use failover route policy?

Answer 17

When you want to require a health check to be made to ensure the downstream system is healthy before returning a DNS record

Question 18

When should you use a geolocation route policy?

Answer 18

When you want to route based on the user location. Be sure to create a default record incase there is no location match

Question 19

When should you use a geoproximity route policy?

Answer 19

When you require the ability to shift more traffic to resources based on a configurable bias value

Question 20

When should you use IP-based route policy?

Answer 20

When you know the CIDRs for your clients ahead of time

Question 21

When should you use multi-value route policy?

Answer 21

When you want to route to multiple different resources and return multiple DNS entries. Related to health checks.