AWS Developer 認證 - Route 53

R53 is global like IAM

Hosted Zones

Simple Policies

• link the domain to the web server
• example.com / the DNS name of the ELB (alias)

Weighted

• 50 50 switch between EC2 instances
• split traffic to multiple resources, 50% to vCurrent, 50% to beta

Latency

• route based on latency (cross region)
• route traffic to the resource that provides the best latency.

Failover

• active-passive failover
• health check the London ELB endpoint
• 2 records: primary and secondary
• e.g. set your primary in your region, and a DR (disaster recovery) site in another region

Geolocation

• by continent or country (e.g. all Europe traffic go to EU London)
• route based on geo location (cross region)
• shift traffic from resources in one location to resources in another.

Traffic Flow

• a visual editor to create a traffic policy
• complex configuration

DNS

search a public ip by a domain name

top Level Domains: .com .gov .edu, second level domain name: .com.au, .http://edu.cn

• SOA Records ()
• NS Records (name server by top level domain servers)
• A Records (domain name to ip address)
• AAAA Records for IPv6
• TTL (cache, time to live)
• CNAMES (canonical domain name to domain name)
• Alias Records (AWS created, easy way to map naked domain name (apex) to resource record / ELB, CF distribution, S3 bucket)

NAME TYPE VALUE--------------------------------------------------bar.example.com. CNAME foo.example.com.foo.example.com. A 192.0.2.23

Tips:

• ELB do not have pre-defined IPv4 addresses, to resolve using a DNS name
• Alias vs CNAME
• choose Alias record over CNAME

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