HA(High-Availability)

Aims to ensure an agreed level of operational performance, usually uptime, for a higher than normal period

FT(Fault-Tolerance)

Property that enables system to continue operating properly in the event of the failure of some of its components

a set of policies, tools, procedures to enable the recovery or continuation of vital technology infrastructure and systems following a natural or human-induced disaster

Route53 allows you:
- register domain
- host zones files on managed name service
Global service but only 1 database
Route 53 is globally resilient

route 53 checks for the registry for that top level domain, if it is available
route 53 creates a zone file(hosted zone) for the domain being registered(zone file: a database contains all DNS information of the domain)
allocates name service for this zone
put zone file onto the 4 managed name servers
connect top level domain registry and add the name server records into the zone file for the (.org or .com or .io or .net) top level domain
you can register a domain using route 53, and put the zone file out side of the AWS name servers
you can also register a domain elsewhere and created hosted zone in route 53 and point the external domain as the route 53 name servers

Nameserver: nameserver inside a zone, point to the servers host subzone:
A and AAAA records: host name for IP address directly. A to IPv4, AAAA to IPv6. Normally, we will create 2 records for the same name(1 for A, another for AAAA):

CNAME Records: This type of record creates an alias for an A record. It points one domain name to another domain name:

MX Records(important for email): A n A record named “mail” inside. Email server looks at 2 addresses of the mail(hi@google.com), focus on the domain: google.com, then using MX query on goole.com:
TXT Records: allows you to add arbitrary text to a domain, often used in domain name verification