AWS Certified Solutions Architect – Professional — Question 101

An organization is planning to host a Wordpress blog as well as joomla CMS on a single instance launched with VPC. The organization wants to create separate domains for each application using Route 53. The organization may have about ten instances each with these two applications. While launching each instance, the organization configured two separate network interfaces (primary + secondary ENI) with their own Elastic IPs to the instance. The suggestion was to use a public IP from AWS instead of an Elastic IP as the number of elastic IPs allocation per region is restricted in the account.
What action will you recommend to the organization?

Answer options

• A. Only Elastic IP can be used by requesting limit increase, since AWS does not assign a public IP to an instance with multiple ENIs.
• B. AWS VPC does not attach a public IP to an ENI; so the only way is to use an Elastic IP.
• C. I agree with the suggestion but will prefer that the organization should use separate subnets with each ENI for different public IPs.
• D. I agree with the suggestion and it is recommended to use a public IP from AWS since the organization is going to use DNS with Route 53.

Correct answer: A

Explanation

The correct answer is A because AWS does not automatically assign public IPs to instances that have multiple ENIs, meaning the only option is to request more Elastic IPs. Option B is incorrect as it ignores the possibility of requesting a limit increase for Elastic IPs. Option C suggests using separate subnets, which does not solve the core issue about public IP assignment. Option D is also incorrect because AWS's policy regarding public IPs for multiple ENIs still stands.