Can I use CNAME records for subdomain and sub-subdomain?

Question

I have created a new subdomain and have a CNAME record to point that subdomain to AWS ELB. Eg.
example.com A 178.2.2.1
abc.example.com CNAME AWS_ELB-1

Now I wanted to create a new subdomain ( basically a sub-subdomain) which points to a different AWS ELB. Eg.
host1.abc.example.com CNAME AWS_ELB-2
host2.abc.example.com CNAME AWS_ELB-3

1. Can I have entries like above ( CNAMEs for subdomain and sub-subdomain)?
2. Do I need to have an A record for subdomain and have CNAMEs for sub-subdomains?

Answer 1

Official AWS recommendation is an A record:

http://docs.aws.amazon.com/Route53/latest/DeveloperGuide/routing-to-elb-load-balancer.html

This makes sense to me, as an A record is when you want to point a domain, subdomain, or even a sub-subdomain at a specific IP address.

CNAME is when you want to define a sub/sub-subdomain/domain that goes to another sub/sub-subdomain/domain. I use this when I want a subdomain that gets served by the same server from subdomain to TLD.

On the difference between A records and CNAMEs:

• https://support.dnsimple.com/articles/differences-between-a-cname-alias-url/
• Note if you are using Route 53, you can reduce a miniscule amount of your bill:
  • "Note Amazon Route 53 doesn't charge for alias queries to ELB load balancers or other AWS resources."
    • If you select "alias record" when populating the A record info in Route 53.