A company wants to host a web application and a database layer in AWS. This will be done with the use of subnets in a VPC. 
What would be a proper architectural design for supporting the required tiers of the application?

Answer options:

A.Use a public subnet for the web tier and another public subnet for the database layer.
B.Use a public subnet for the web tier and a private subnet for the database layer.
C.Use a private subnet for the web tier and another private subnet for the database layer.
D.Use a private subnet for the web tier and a public subnet for the database layer.

Correct Answer – B
The ideal setup is to ensure that the webserver is hosted in the public subnet so that users on the internet can access it. The database server can be hosted in the private subnet.
The below diagram shows how this can be set up:
For more information on public and private subnets in AWS, please visit the following URL:
https://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_Scenario2.html