Section 9: Route 53

Question 1

True/False
Domain Name System translates human friendly hostnames into machine IP addresses

Answer 1

True

Question 2

What’s the amazon domain registrar?

Answer 2

Amazon Route 53

Subsection: What is a DNS?

Question 3

Tell me about all the parts of this URL
http://api.www.example.com.

(Things like which part represent the fully qualified domain name, which part represents the top level domain, etc.)

Answer 3

Ignore the underlines, they’re not supposed to be there.
* URL: http://api.www.example.com.
* protocol: http
* Fully Qualified Domain Name (FQDN): api.www.example.com.
* sub domain: .www.example.com.
* second level domain (SLD): .example.com.
* Top Level Domain (TLD): .com.
* Root: . <- that’s the period after the com

Subsection: What is a DNS?

Question 4

Is Amazon Route 53 highly available, scalable, Authoritative DNS, Domain Registrar, with the ability to check the health of your resources and the only AWS service which provides 100% availability SLA?

Answer 4

Yes

Subsection: Route 53 Overview

Question 5

What’s an Authoritative DNS?

Answer 5

It means the customer (me) can update the DNS records (as opposed to who? I’m not sure).

Subsection Route 53 Overview

Question 6

About Route 53 records:

What are the names of the following
* A) there are many types of these, but you must know A, AAAA, CNAME, NS
* B) ex: 12.34.56.78
* C) how Route 53 responds to queries
* D) amount of time the record cached at DNS resolvers
* E) ex: example.com

Answer 6

• A) Record Type
• B) Value
• C) Value
• D) TTL
• E) Domain/subdomain name

Subsection Route 53 Overview

Question 7

About Route 53, identify the following description with the appropriate record type:

• A) maps a hostname to IPv4 (ex: 1.2.3.4)
• B) maps a hostname to IPv6 (ex: 1.2.3.4.5.6)
• C) maps a hostname to another hostname.
• D) name servers for the hosted zone that control how traffic is routed for a domain.

Answer 7

Subsection: Route 53 Overview

Question 8

Which of the following, if any, are false about CNAMEs and what is/are the true version(s)?

• A) Can’t create a CNAME record for the top node of a DNS namespace (zone apex). For example, you can’t create one of these for www.example.com, but you can do it for example.com.
• B) target is a domain name which must have an A or an NS record.

Answer 8

• A) is false, here’s the true version: Can’t create a CNAME record for the top node of a DNS namespace (zone apex). For example, you can’t create one of these for example.com, but you can do it for www.example.com.

*B) is false. Here’s the true version: target is a domain name which must have an A or an AAAA record.

Subsection: Route 53 Overview

Question 9

Route 53 - Hosted Zones
true/false. you can have private or public hosted zones (public domain names) (ones that route traffic on the internet or ones that route traffic within a private network (VPC)) (private domain names). These are not free. at time of course section creation, cost was 50 cents a month.

Answer 9

True

Subsection: Route 53

Question 10

Say you have a registered domain, example.com and you go to your hosted zones and you want to make a new subdomain, test.example.com. What’s the button you click to create the subdomain?

Answer 10

Create record!

Subsection: Route 53

Question 11

Route 53 Records TTL:
True/False;

Route 53 Records TTL concerns the amount of time Route 53 tells you to cache the IP address associated with the domain name you (a client) requested. A longer TTL (ex: 24 hours) means fewer requests querying the DNS and less traffic on Route 53 (and each request or the overall traffic will cost you $). But it also means that if you change something, it will take longer for all your clients to get the new info. Opposite is true for shorter TTL. So shorter TTL is better if you expect you want to change your records often and don’t mind the cost, then you’d want a short TTL (ex, 60 seconds).

Answer 11

True

Subsection: Route 53 - TTL

Question 12

CNAME:
point a hostname to any other hostname
ALIAS: point a hostname to a specific AWS resources

this question isn’t done, but i’m not sure i like it anway

Answer 12

Subsection: Route 53 CNAME vs Alias

Question 13

Why is an A type Alias record better than CNAME for getting to your AWS resource?

rubythroatedhummingbird.gulfcoastcloud.com and northerncardinal.gulfcoastprairie.com now also gets you to this location. I purchased the domain name gulfcoastcloud.com was purchased through Amazon Route 53. The subdomain “hummingbird” was created as an a type A record attached to the aforementioned application load balancer by using the Alias option in the create record form. The subdomain ”northerncardinal” was created using a type CNAME record attached to the DNS name of the same application load balancer. Honestly, I’m not quite sure what the difference between the two approaches is. The A method used the same DNS name as the CNAME method, only there was a different way to get there and “dualstack” was appended in front of the string. A quick search would make it seem that dualstack means that your domain can use IPv4 and IPv6 records, except that since the A method is the A method, I expected it to only use IPv4.

Answer 13

it seems like the alias record is free to query, but CNAME is not. That would make A-alias better than CNAME.

Subsection: Route 53 CNAME vs Alias

Question 14

you have a domain, example.com and an ALB that is hooked up to sites (identical) on two ec2 instances. You want to connect example.com to the ALB so people can see your site using the URL “example.com”. Can you use an A type record? What about a CNAME type record?

Answer 14

You can use an A type record with an alias that you set up by selecting endpoint “route to application or classic load balancer”, region whatever-your-region-is, and selcting the appropriate load balancer. No, you cannot do this with CNAME. I suspect you can do it with IPv6 but possibly not with any other of the 4 main record types.

Subsection: Route 53 CNAME vs Alias

Question 15

What are the four main record types?

Answer 15

A, AAAA, CNAME, NS

Subsection - Route 53 - Creating our first records (this is a guess)

Question 16

True/False: Route 53 routing policies refer to routing DNS queries, not traffic

Answer 16

True

Subsection: Routing Policy - Simple

Question 17

True/False: the following comprises the list of Route 53 Routing policies: Simple, weighted, failover, threshold based, geolocation, multi value answer, geoproximity (using route 53 traffic flow feature)

Answer 17

False. Correct answer is:
Simple, weighted, failover, latency based, geolocation, multi value answer, geoproximity (using route 53 traffic flow feature)

Subsection: Routing Policy - Simple

Question 18

True / False: The following describes the Latency-based Routing Policy
* Used to route traffic to a single resource
* can specify multipel values in the same record
* if multiple values are returned, a random one is chosen by the client
* when alias is enabled, can only specify one AWS resource per target
* can’t be associated with a health check

Answer 18

False. It describes Simple Routing Policy

Subsection: Routing Policy - Simple

Question 19

Can i use two values (IP addresses) in one type A non-alias-using record?

Answer 19

Yes, just put one on the first line and press enter and put the other on the second line.

Subsection: Routing Policy - Simple

Question 20

True/False does the following describe Simple Routing Policies?
* Control the % of the requests that go to each specific resource by assigning each record a relative ____
* traffic % per ec2 instance equals ____ for a specific record divided by the sum of all the ____ for all records. this is a lot simpler than it sounds. it’s just like if you have 3 instances with ____ of 70, 20 and then 10 then the first instance gets 70% of traffic, the second gets 20% and the third gets 10%.
* dns records must have the same name and type
* can be associated with health checks
* use bases: load balancing between regions, testing app versions (slow rolling?)
* assign a ____ of 0 to stop sending traffic to a record/the instance it points to
* if all records have a ____ of 0, all records gets traffic equally (not sure he didn’t mean instances?)

Answer 20

False, it described Weighted Routing Policies

Subsection: Routing Policy - Weighted

Question 21

When creating one weighted routing policy record, can each sub-record have a different TTL? Can you put a different value in each subrecord?

Answer 21

No, they must have the same TTL. Yes.

Subsection: Routing Policy - Weighted

Question 22

True/False does the following describe Weighted routing policies?
* Redirect the resouce that has the least ____ close to us
* super helpful when ____ for users is a priority
* ____ is based on traffic between users and AWS regions
* germany users may be directed to the US (if that’s the lowest ____)
* can be associated with health checks (has failover capability)

Answer 22

False. It described Latency-based routing policies

Subsection: Routing Policy - Latency

Question 23

True/False is the following True about Route 53 Health Checks?
* http health checks are only for public resources
* health checks lead to automated dns failover: monitor an endpoint; other health checks; cloud watch alarms like throttles on dynamo db, alarms on rds, custom metrics
* health checks are integrated with CloudWatch metrics

Answer 23

True

Subsection: Route 53 Health Checks

Question 24

True/False
About Route 53 health checks
* only pass when the endpoint responds with 2xx or 3xx status codes
* can be set up to pass/fail based on text in the first 5120 bytes of the response
* you must configure your router/firewall to allow incoming requests from Route 53 Health Checks
* about 15 global health checkers will check the endpoint health: healthy/unhealthy threshold - 3 (default); interval: 30 second (can set to 10 sec, higher cost); supports HTTP, HTTPS and TCP; if more than 18% of the heath checkers report hte endpoint is healthy, route 53 considers it health - otherwise it’s unhealthy; ability to choose which locations you want Route 53 to use

Answer 24

True

Subsection: Route 53 Health Checks

Question 25

True/False Route 53 Calculated Health Checks * A) you cannot combine the results of multiple health checks into a single health check * B) you can use OR, AND, or NOT * C) can monitior up to 518 Child Health Checks * D) Specify how many health checks need to pass to make the parent pass * E) Usage example: perform maintenance to your website without causing all the health checks to pass

Answer 25

* A) is false. You* can. * * C) is false. 256 ## Footnote Subsection: Route 53 Health Checks

Question 26

True/False: Health Checks on Private Hosted Zones * A) Route 53 health checkers are outside the VPC * can't access private endpoints (private VPS or on-premises resources) * you can create CloudWatch Metic and associated CloudWatch Alarm, then create a Health Check that checks the alarm itself

Answer 26

True ## Footnote Subsection: Route 53 Health Checks

Question 27

True/False about Routing Policy - Failovers (Active / Pass) Amazon Route 53 uses a health check to check the status of the primary ec2 instance and will move traffic to the failover ec2 instance

Answer 27

True ## Footnote Subsection: Routing Policy - Failovers

Question 28

True/False about Routing Policies - Geolocation * A) Based on user location * B) specify location by continent, country, or US state (most precise location wins) * C) should create a default record in case there's no location match * D) use cases: website localization, restrict content distribution, load balancing * E) can be associated with health checks This one means that people are routed to values (IP addresses, for example, the ipv4 address of an ec2 instance) according to where they are. So we make a record, create a subrecord, put in a value, and say that anyone in north america goes to that value. Then in that same record we make another subrecord and put a value in there (say 11.22.33.44) and this time set the value to default, so this means that if a user doesn't belong to any other location we've listed (so far just North America, then they're in a default location and they go to value 11.22.33.44)

Answer 28

True ## Footnote Subsection: Routing Policices - Geolocation

Question 29

True/False about Geoproximity Routing Policy * A) Route traffic to resources based on geographic location of users and resources * B) ability to shift traffic to resources based on defined bias * C) to change the size of a geographic regino, specify bias values. To expand (1-99) more traffic to resources. To shrink (-1 to -99) - less traffic to the resource * D) resources can be AWS or non AWS, you just specify the latitude and longitude either way. * E) you must use Route 53 traffic flow (advanced) to use this feature

Answer 29

* D) is false. For AWS resources you specify the AWS region. It's only for non-AWS resources that you specify the latitude and longitude. ## Footnote Subsection: Routing Policy - Geoproximity

Question 30

True/False Say you've got a resource in us-west-1 and us-east-1, both with a bias of 0. That means that you can picture America cut in half, and people closer to us-west-1 go to us-west-1 and people closer to us-east-1 go to us-east-1. Now say that us-east-1 (which is right half of american in this story) gets a high bias (say 50). Now the line separating the right and left half of america is not in the middle anymore. Instead the right half of america is waaay bigger. Now everbody in the now-much-bigger right half gets directed to us-east-1, and everyone in the now-much-smaller left half gets directed to us-west-1

Answer 30

True ## Footnote Subsection: Routing Policy - Geoproximity

Question 31

Route 53 Traffic Flow True/False * A) Simplify the process of creating and maintaining records in large and complex configs * B) visual editor to manage complex routing decision trees * C) Configs can be saved as Traffic Flow Poilcy: Can be applied to different Route 53 Hosted Zones (different domain names); supports versioning

Answer 31

True ## Footnote Subsection: Routing Poilcy - Traffic Flow and Geoproximity Hands on

Question 32

True/False IP based Routing * A) routing based on clients' IP addresses * B) you provide al ist of CIDRs for your clients and the corresponding endpoints/locations (user-IP-to-endpoint mappings) * C) Use cases: optimize performance, reduce network costs * D) example: route end users from a particular ISP to a specific endpoint

Answer 32

True ## Footnote Subsection: Routing Policy - IP-based

Question 33

Route 53. You create a record. you specify a subrecord (aws never calls them that, but it's what I imagine creating when I create more than one record on the same form that was generated when i clicked the 'Create Record' button once) with an IP based routing policy. You set the value to 11.22.33.44 (say that goes to a site on one ec2 instance). You enter a CIDR collection (location-1 for CIDR blaock 203.0.113.0/24). Then you create another subrecord, set the value to 22.33.44.55 (say that goes to a site on another ec2 instance) and enter a CIDR block 200.5.4.0/24. Then say user A comes along from 203.0.113.56. Which ec2 instance do they go to? What about user B who's coming along from 200.5.4.100?

Answer 33

User A is from CIDR block 203.0.113.0/24 so they go to the ec2 instance site at 11.22.33.44. User B is from CIDR block 200.5.4.0/24 and so goes to ec2 instance site at 22.33.44.55 ## Footnote Subsection Routing Policy - IP-based

Question 34

True/False about Routing Policies - Multi Value * A) Use when routing traffic to multiple resouces * B) Route 53 return multiple values/resouces * C) can be associated with health checks (return only values for healthy resources) * D) Up to 8 healthy records are returned for each multi value query * E) Multi-Value is not a subsistute for having an ELB. The idea is that you have client side load balancing (you should probably look that up and add some info)

Answer 34

True ## Footnote Subsection: Routing Policy - Multi Value

Question 35

True/False about 3rd Party Domains & Route 53 Domain Registrar vs DNS Service * A) you buy or registrar your domain name with a Domain Registrar typically by paying annual charges (GoDaddy, Amazon Registrar etc) * B) The Domain Registrar usually provides you with a DNS service to manage your DNS records, and you cannot use another DNS service to manage your DNS records. For example, if you purchase the domain from GoDaddy you cannot use Route 53 to manage your DNS records.

Answer 35

B is False. Here's the correct version: The Domain Registrar usually provides you with a DNS service to manage your DNS records, but you can use another DNS service to manage your DNS records. For example, if you purchase the domain from GoDaddy you can use Route 53 to manage your DNS records. To do this you: 1) create a hosted zone in Route 53. 2) Then you update NS Records on 3rd party website (like godaddy) to use route 53 name servers. Note that a Domain Registrar is not the same as a DNS Service, but every Domain Registrar comes with some DNS features ## Footnote Subsection: 3rd Party Domains & Route 53

Question 36

Answer 36

Alias: no notes. Incorrect answer notes: CNAME: Incorrect answer. Please try again. You can't create a CNAME record that has the same name as the top node of the DNS namespace (Zone Apex), in our case mycoolcompany.com. ## Footnote Subsection: Route 53 Quiz

Question 37

Answer 37

Correct: Weighted. Good job! Weighted Routing Policy allows you to redirect part of the traffic based on weight (e.g., percentage). It's a common use case to send part of traffic to a new version of your application. incorrect answers have no notes ## Footnote Subsection: Route 53 Quiz

Question 38

Answer 38

Correct answer: TTL. Good job! Each DNS record has a TTL (Time To Live) which orders clients for how long to cache these values and not overload the DNS Resolver with DNS requests. The TTL value should be set to strike a balance between how long the value should be cached vs. how many requests should go to the DNS Resolver. Incorrect answers have no notes. ## Footnote Subsection: Route 53 Quiz

Question 39

Answer 39

Correct answer: Latency Good job! Latency Routing Policy will evaluate the latency between your users and AWS Regions, and help them get a DNS response that will minimize their latency (e.g. response time) Incorrect answers have no notes. ## Footnote Subsection: Route 53 Quiz

Answer 40

## Footnote Subsection: Route 53 Quiz

Question 41

Answer 41

Geolocation. no answers have notes. ## Footnote Subsection: Route 53 Quiz

Question 42

Answer 42

correct answer: Create a Public Hosted Zone and update the 3rd party Registrar NS records. Notes: success alert Good job! Public Hosted Zones are meant to be used for people requesting your website through the Internet. Finally, NS records must be updated on the 3rd party Registrar. Incorrect answer notes: * Private hosted zone - error alert Incorrect answer. Please try again. Private Hosted Zones are meant to be used for internal network (e.g., VPC) DNS queries and are not publicly accessible. no other answers have incorrect notes. ## Footnote Subsection: Route 53 Quiz

Question 43

Answer 43

Answer: Health checks that monitor SQS Queue. No answers have notes. ## Footnote Subsection: Route 53 quiz