DNS, Caching, Performance Optimization

Question 1

Hosted Zone

Answer 1

represents a set of records that belong to a domain that allow DNS to query for the IP address that aligns to the domain

Question 2

Route53

Answer 2

Advanced DNS service

Question 3

List Route53 Routing Policies

Answer 3

Simple
Failover
Geolocation
Geoproximity
Latency
Multivalue answer
Weighted
IP-Based

Question 4

Simple Routing Policy

Answer 4

Simple DNS response providing the IP address associated with a name

Responds to DNS queries

Configure DNS records with domain name to multiple/single IP with TTL

Question 5

Failover Routing Policy

Answer 5

If primary is down (based on health checks), routes to secondary destination

has a primary and secondary record type

Question 6

Geolocation Policy

Answer 6

Uses geographic location of client in e.g. Europe to route you to the closest region

has name, type, value, health, and geolocation

Health checks are optional

Question 7

Geoproximity Policy

Answer 7

Routes you to the closest region within a geographic area

Uses traffic flow, must create a policy in traffic flow - specify coordinates to route to endpoints that include CloudFront, Elastic Beanstalk, S3, and IP addresses

Question 8

Latency Policy

Answer 8

Directs you a region based on the lowest latency route to resources

has name, value, record type, health id and region

value can be load balancer or IP

Health checks are optional

Question 9

Multivalue answer Policy

Answer 9

Returns several IP addresses and functions as a basic load balancer

Health check returns only healthy records

Question 10

Weighted Policy

Answer 10

Uses the relative weights assigned to resources to determine which to route to

Configure DNS records with domains, IP and weight so that traffic is routed to be proportional to the record according to the configured weight

Weights can be between 0 -255 (simplified values) or percentages

Health checks are optional

Question 11

IP Based Policy

Answer 11

Uses the IP addresses of clients to make routing decisions

Create CIDR collections = are used to define IP addresses and CIDR blocks of clients

Routing rules can be created to route based on CIDR collection

Question 12

Top Level domain

subdomain

hostname

Answer 12

last word of a Fully qualified domain name, e.g. com

Subdomains are everything outside of the top level e.g. example.com - example is subdomain; subdomain is subdivision of a domain name for organizing a set of related resources or services

first word in domain name (www.example.com)

Question 13

Route 53 Features

Answer 13

Domain name registration
Hosted zones (support DNS resolution, query)
Health checks
Traffic flow

Question 14

A record type

Answer 14

maps a domain name to an IP address

Question 15

CNAME record type

Answer 15

maps a domain name to another domain name

Question 16

MX records

Answer 16

returns mail servers for domain name

Question 17

TXT records

Answer 17

Associated text with a domain name (used for verification/authz)

Question 18

SRV records

Answer 18

maps a domain name to a specific service or protocol

Question 19

NS

Answer 19

specifies the authoritative DNS server for a particular domain

Question 20

SOA

Answer 20

Start of Authority records stores important information about a domain

Question 21

Public vs Private hosted zones

Answer 21

public hosted zone is accessible to the internet; created by default for new domain registrations

private zones can be used for internal AWS routing within you account

Question 22

Route53 health checks

Answer 22

perform health checks against EC2 instances, load balancers, and other IP endpoints

enable active passive failover - send traffic to other resources based on health

Question 23

Route53 Resolver

Answer 23

Allows Route53 to be forward request to another DNS server for DSN resolution

Question 24

Route53 Resolver Outbound Endpoint - describe configuration and provide typical use case

Answer 24

DNS server in corporate data center
VPN connects VPC to coporate data centet via customer gateway and VGW

Route53 is configured with Outbound Endpoint (in VPC subnets where DNS query could come from?), so that when AWS resource request item in corporate data center AWS will look up the record in Route53, Route53 will return the Outbound Endpoint location, which will forward to the corporate DNS for resolution

Question 25

Route53 Resolver Inbound Endpoint - describe configuration and provide typical use case

Answer 25

DNS server on corporate data center
VPN connects VPC to coporate data centet via customer gateway and VGW
Inbound Endpoint configured in VPC subnets, so that when client in the corporate data center request a resource results are returned by Route53 via the inbound endpoint

Question 26

CloudFront

Answer 26

CDN Content delivery network

get content closer to users

Question 27

CloudFront Origin

Answer 27

Origin of content (e.g. S3, EC2, etc)

Question 28

Edge Location

Answer 28

Caches all all over the world where users connect that connect to AWS resources using AWS Global Network (low latency, consistency, high throughput and performance)

content from the origin gets pushed from origin out and cached at the ede locations

Question 29

CloudFront Web Distribution

Answer 29

what you create in cloud front

speed up distribution of static and dynamic content
Distribute media files using HTTP/S
Add, update, or delete objects, and submit data from web forms
Use live streaming to stream an event in real time

Question 30

What behaviors can you configure in a Cloud Front Distribution

Answer 30

Path Pattern - direct to origin based on path (e.g. go to S3 bucket a or EC2 depending on path)
Viewer Protocol Policy - e.g. redirect to https
Cache Policy - ttl
Origin Request Policy

Question 31

Regional Edge Cache

Answer 31

12 edge caches that sit between edge locations and regions (vs 210 edge locations)

large cache to hold more content

Question 32

How long is the default TTL for CloudFront?

Answer 32

24 hours

Question 33

When does an object have to fetched from CloudFront origin?

Answer 33

When there is a Cache MISS at the edge location and regional edge location

Question 34

When should you reduce TTL?

When should you increase TTL?

Answer 34

for dynamic content

for better performance and reduce load on origin