AWS Certified Advanced Networking – Specialty ANS-C00 – Question332

You have a web application (app.mycompany.com) running on an EC2 instance with a single elastic network interface in a subnet in a VPC. Because of a network redesign, you need to move the web application to a different subnet in the same Availability Zone.
Which of the following migration strategies meets the requirements?

A.
Create an elastic network interface in the new subnet. Attach this interface to the instance, and detach the old interface.
B. Launch a new instance in the subnet via an AMI created from the instance, and redirect new connections to this new instance using DNS. Decommission the old instance.
C. Make an API call to change the subnet association of the elastic network interface.
D. Change the IP addresses manually to another subnet within the server operating system.

Correct Answer: B

Explanation:

Explanation:
Instances cannot change subnets, so a new instance must be created (Response B). A is wrong because you cannot remove the original elastic network interface. C is not possible. D is wrong because the OS has no ability to affect the AWS assigned IP addresses.