Route 53

Question 1

What is Route 53?

Answer 1

• An AWS Managed DNS system
• Can use either public or private domain names
• Can provide options for load balancing, health checks, and routing policies
• Costs $$ (currently $0.50/month/hosted zone)

Question 2

What are the 4 most common DNS records used in AWS? Explain each one.

Answer 2

1. A: hostname to IPv4
2. AAAA: hostname to IPv6
3. CNAME: hostname to hostname
4. ALIAS: hostname to AWS resource

Question 3

What is DNS Time to Live (TTL)?

Answer 3

How long a URLs cached IP address remains cached in the browser before making a request to the actual DNS server

Question 4

What are the main differences between a CNAME record and an ALIAS record?

Answer 4

CNAME:

• costs $
• can NOT be associated with a ROOT domain (i.e mySite.com)

ALIAS (recommended):

• Free
• Works for both root and non-root domain names
• Provides options for health checks

Question 5

What are the 5 types of routing policies available through Route 53?

Answer 5

1. Simple
2. Weighted
3. Latency
4. Failover
5. Geolocation

Question 6

What is a Route 53 Simple Routing policy?

Answer 6

• Maps a hostname to another hostname
• use when you need to redirect to a single source
• You can not attach a heath check
• If multiple values are returned for the DNS server, a random one is chosen by the client.

Question 7

What is a Routed 53 weighted routing policy?

Answer 7

• Can control the percent of the requests that go to a specific endpoint
• Hepful to test 1% of traffic on new app version
• Hepful to split traffic between two or more regions
• Can be associated with health checks

Question 8

What is Route 53 Latency Routing Policy?

Answer 8

• User is directed to the server that will result in the least amount of latency
• Good when latency is the priority
• Latency is evaluated in terms of user to designated AWS region

Question 9

What is Route 53 Failover Routing Policy?

Answer 9

• Involves having 2 EC2 instances, one being a primary and the ther a secondary (aka disaster recovery) meant to only be used if primary fails
• Health checks are mandatory that checks primary all the time. If primary fails route 53 will automatically failover to the secondary EC2 server.

Question 10

What is Route 53 GeoLocation Routing?

Answer 10

• Soley based on user location. Different from latency in that the EC2 instance user is routed to may not necessarily correspond to the server where there is the least amount of latency.
• Example. All traffic from Utah goes to a specifc IP and all traffic from North Carolina goes to a different specif IP. Then theres a default EC2 server for all non-specofoed locations to be routed to

Question 11

.What is Route 53 Muti-Value Routing Policy?

Answer 11

• Use when routing traffic to multiple resources.
• Want to associate a Route 53 health check with records
• Up to 8 healthy records are returned for each multi value query
• Multi Value is NOT a substiture for having an ELB

Question 12

What are halth checks in Route 53?

Answer 12

If a health check fails in route 53, then route 53 will not send traffic to the EC2 server (just like a health check for an ELB). In this case you would want a route 53 routing policy that allows health checks and can route to alternative routes.

Only routing policy that does NOT have a hralth check in the simple routing policy