Route 53 Flashcards
(62 cards)
1
Q
What is DNS?
A
Domain Name System translates hostnames into the machine IP addresses
2
Q
4 types of DNS Records Route 53 supports:
A
A, AAAA, CNAME, NS,
3
Q
What does the Zone File contain?
A
DNS records
4
Q
What does the Name Server do?
A
resolves DNS queries (Authoritative or Non-Authoritative)
5
Q
What are Top Level Domain (TLD)?
A
.com, .us, .in, .gov, .org,
6
Q
What are Second Level Domain (SLD)?
A
amazon.com, google.com
7
Q
What are the parts of a standard URL address?
A
Protocol, Full Qualified Domain Name, Sub Domain, Second Level Domain, Top Level Domain, Root
8
Q
What is Amazon Route 53?
A
A highly available, scalable, fully managed and Authoritative DNS
9
Q
What is Authoritative ?
A
The customer (you) can update the DNS records
10
Q
The only AWS service which provides …… availability SLA(service level argement)
A
100%
11
Q
What are Records?
A
How you want to route traffic for a domain.
12
Q
What does each record contain?
A
- Domain/subdomain Name
- Record Type
- Routing Policy
- TTL
13
Q
What is a Routing Policy?
A
How Route 53 responds to queries
14
Q
RecordTypes - A:
A
Maps a hostname to IPv4
15
Q
RecordTypes - AAAA:
A
Maps a hostname to IPv6
16
Q
RecordTypes - CNAME:
A
Maps a hostname to another hostname
17
Q
CNAME rules:
A
- The target is a domain name which must have an A or AAAA record
- Can’t create a CNAME record for the top node of a DNS namespace (Zone Apex)
18
Q
RecordTypes - NS:
A
Name Servers for the Hosted Zone
19
Q
What does NS do?
A
Control how traffic is routed for a domain
20
Q
What is a Hosted Zones?
A
A container for records that define how to route traffic to a domain and its subdomains
21
Q
Public Hosted Zones –
A
Contains records that specify how to route traffic on the Internet (public domain names)
22
Q
Private Hosted Zones –
A
Contain records that specify how you route traffic within one or more VPCs (private domain names)
23
Q
Features of High TTL – e.g., 24 hr
A
- Less traffic on Route 53
- Possibly outdated records
24
Q
Features of Low TTL – e.g., 60 sec.
A
- More traffic on Route 53 ($$)
- Records are outdated for less time
- Easy to change records
25
Except for....... records, TTL is mandatory for each..... record
Alias, DNS
26
What is an Alias record?
Points a hostname to an AWS Resource (app.mydomain.com => blabla.amazonaws.com)
27
Alias rules:
- Works for ROOT DOMAIN and NON ROOT DOMAIN (aka mydomain.com)
- Free of charge
- Native health check
28
Record Types - Alias:
Maps a hostname to an AWS resource
29
Features:
- An extension to DNS functionality
- Automatically recognizes changes in the resource’s IP addresses
- You can’t set the TTL
Alias record type
30
........ is always of type......... for AWS resources
Alias Record, A/AAAA(IPv4 / IPv6)
31
Alias Record Targets
- Elastic Load Balancers
- CloudFront Distributions
- API Gateway
- Elastic Beanstalk environments
- S3 Websites
- VPC Interface Endpoints
- Global Accelerator accelerator
- Route 53 record in the same hosted zone
32
What can you not set an Alias record for?
EC2 DNS name
33
How does a "routing policy" work?
- It’s not the same as Load balancer routing which routes the traffic
- DNS does not route any traffic, it only responds to the DNS queries
34
Route 53 Supports the following Routing Policies:
- Simple
- Weighted
- Failover
- Latency based
- Geolocation
- Multi-Value Answer
- Geoproximity (using Route 53 Traffic Flow feature)
35
Features of Routing Policies - Simple (5)
- Typically, route traffic to a single resource
- Can specify multiple values in the same record
- **If multiple values are returned, a random one is chosen by the client**
- When Alias enabled, specify only one AWS resource
- Can’t be associated with Health Checke
36
Features of Routing Policies - Weighted (5)
- Control the % of the requests that go to each specific resource
- Assign each record a relative weight:
traffic (%) = Weight for a specific record / Sum of all the weights for all the records
- Weights don’t need to sum up to 100
- DNS records must have the same name and type
- Can be associated with Health Checks
37
Use cases for Weighted policy:
- load balancing between regions
- testing new application versions...
38
Weighted policy - how do you stop sending traffic to a resource?
Assign a weight of 0 to a record to stop sending traffic to a resource
39
Weighted policy - what happens if all records how a weight of 0?
If all records have weight of 0, then all records will be returned equally
40
Features Routing Policy - Latency(3)
- Redirect to the resource that has the least latency close to us
- Super helpful when latency for users is a priority
- Can be associated with Health Checks (has a failover capability)
41
Latency policy - what is latency based on?
Latency is based on traffic between users and AWS Regions
42
HTTP Health Checks are only for....... ............
public resources
43
What do **Health Checks** provide?
Automated DNS Failover
44
What are the 3 possible **Health Checks**?
1.Health checks that monitor an endpoint
2. Health checks that monitor other health checks
3.Health checks that monitor CloudWatch Alarms
45
Health Checks are...... with ...... metrics
integrated, Cloud Watch
46
Health Checks pass only when the endpoint responds with...
The 2xx and 3xx status codes
47
Health Checks can be setup to pass / fail based on the text in ....
The first 5120 bytes of the response
48
Configure you ....... to allow incoming requests from Route 53 Health Checkers
router/firewall
49
What is a **Calculated Health Checks**?
Combining the results of multiple Health Checks into a single Health Check
50
Can monitor up to ..... Child Health Checks
256
51
With Calculated Health Checks you can specify how many of the ...
health checks need to pass to make the parent pass
52
Where are Private Hosted Zones done?
Route 53 health checkers are outside the VPC
53
Health Checks cannot access ...
private endpoints (private VPC or on-premises resource)
54
Features of routing Policy: **Failover**
Routes traffic to a resource when the resource is healthy or to a different resource when the first resource is unhealthy.
55
Features of routing Policy: **Geolocation**
- Routing is based on user location
-Specify location by Continent, Country or by US State (if there’s overlapping, most precise location selected)
-Should create a “Default” record (in case there’s no match on location)
- Can be associated with Health Checks
56
Use cases for Geolocation policy:
website localization, restrict content distribution, load balancing, ...
57
Features of routing Policy: **Geoproximity**
- Route traffic to your resources based on the geographic location of users and resources
- Ability to shift more traffic to resources based on the defined bias
-You must use Route 53 Traffic Flow to use this feature
58
How is the bias defined in a Geoproximity policy?
- To change the size of the geographic region, specify bias values:
- To expand (1 to 99) – more traffic to the resource
- To shrink (-1 to -99) – less traffic to the resource
59
What are the **Geoproximity** resources?
- Resources can be:
- AWS resources (specify AWS region)
- Non-AWS resources (specify Latitude and Longitude)
60
Features of routing Policy: **IP - based**
- Routing is based on clients’ IP addresses
- You provide a list of CIDRs for your clients and the corresponding endpoints/locations (user-IP-to-endpoint mappings)
61
Use cases for **IP based** policies:
Optimize performance, reduce network costs...
62
Features of routing Policy: **Multi Value**
- Use when routing traffic to multiple resources
- Route 53 return multiple values/resources
- Can be associated with Health Checks (return only values for healthy resources)
- Up to 8 healthy records are returned for each Multi-Value query
- Multi-Value is not a substitute for having an ELB(The idea is that it's the client-side load balancing)
