AWS Certified Solutions Architect – Professional — Question 825
An AWS customer is deploying an application mat is composed of an AutoScaling group of EC2 Instances.
The customers security policy requires that every outbound connection from these instances to any other service within the customers Virtual Private Cloud must be authenticated using a unique x 509 certificate that contains the specific instance-id.
In addition, an x 509 certificates must Designed by the customer's Key management service in order to be trusted for authentication.
Which of the following configurations will support these requirements?
Answer options
- A. Configure an IAM Role that grants access to an Amazon S3 object containing a signed certificate and configure the Auto Scaling group to launch instances with this role. Have the instances bootstrap get the certificate from Amazon S3 upon first boot.
- B. Embed a certificate into the Amazon Machine Image that is used by the Auto Scaling group. Have the launched instances generate a certificate signature request with the instance's assigned instance-id to the key management service for signature.
- C. Configure the Auto Scaling group to send an SNS notification of the launch of a new instance to the trusted key management service. Have the Key management service generate a signed certificate and send it directly to the newly launched instance.
- D. Configure the launched instances to generate a new certificate upon first boot. Have the Key management service poll the Auto Scaling group for associated instances and send new instances a certificate signature (hat contains the specific instance-id.
Correct answer: C
Explanation
Option C is correct because using an SNS notification triggered by the Auto Scaling group allows the key management service to immediately react to new instances, generate a uniquely signed x.509 certificate containing the instance-id, and securely push it to the instance. Other options fail because retrieving a pre-signed certificate from Amazon S3 (Option A) does not provide a unique certificate per instance-id, while having the instance initiate the request first (Option B) or relying on polling (Option D) are either insecure or highly inefficient.