AWS Certified Solutions Architect – Professional — Question 735

A solutions architect has launched multiple Amazon EC2 instances in a placement group within a single Availability Zone. Because of additional load on the system, the solutions architect attempts to add new instances to the placement group. However, the solutions architect receives an insufficient capacity error.

What should the solutions architect do to troubleshoot this issue?

Answer options

• A. Use a spread placement group. Set a minimum of eight instances for each Availability Zone.
• B. Stop and start all the instances in the placement group. Try the launch again.
• C. Create a new placement group. Merge the new placement group with the original placement group.
• D. Launch the additional instances as Dedicated Hosts in the placement groups.

Correct answer: B

Explanation

An insufficient capacity error occurs when the specific physical hardware hosting the cluster placement group lacks the capacity to launch new instances. Stopping and restarting all instances in the placement group allows AWS to migrate the entire group to a different hardware segment that has enough contiguous capacity for both existing and new instances. Other options, like merging placement groups or using a spread placement group with eight instances per Availability Zone (which violates the limit of seven per AZ), are unsupported or invalid.