AWS Certified Solutions Architect – Professional — Question 732

A solutions architect needs to review the design of an Amazon EMR cluster that is using the EMR File System (EMRFS). The cluster performs tasks that are critical to business needs. The cluster is running Amazon EC2 On-Demand Instances at all times for all task, master, and core nodes. The EMR tasks run each morning, starting at 1:00 AM. and take 6 hours to finish running. The amount of time to complete the processing is not a priority because the data is not referenced until late in the day.

The solutions architect must review the architecture and suggest a solution to minimize the compute costs.

Which solution should the solutions architect recommend to meet these requirements?

Answer options

• A. Launch all task, master, and core nodes on Spot Instances in an instance fleet. Terminate the duster, including all instances, when the processing is completed.
• B. Launch the master and core nodes on On-Demand Instances. Launch the task nodes on Spot Instances in an instance fleet. Terminate the cluster, including all instances, when the processing is completed. Purchase Compute Savings Plans to cover the On-Demand Instance usage.
• C. Continue to launch all nodes on On-Demand Instances. Terminate the cluster, including all instances, when the processing is completed. Purchase Compute Savings Plans to cover the On-Demand Instance usage
• D. Launch the master and core nodes on On-Demand Instances. Launch the task nodes on Spot Instances in an instance fleet. Terminate only the task node instances when the processing is completed. Purchase Compute Savings Plans to cover the On-Demand Instance usage.

Correct answer: D

Explanation

Using On-Demand Instances for the master and core nodes ensures cluster stability and prevents data loss, while leveraging Spot Instances for the task nodes significantly reduces compute costs during the daily 6-hour workload. Terminating only the task nodes after processing finishes stops Spot Instance charges while keeping the primary cluster structure available. Additionally, purchasing Compute Savings Plans helps minimize the ongoing cost of the running On-Demand master and core instances.