AWS Certified Solutions Architect – Associate (SAA-C02) — Question 687

A company has a stateless, asynchronous application that runs in an Apache Hadoop cluster. The application is invoked on demand to run extract, transform, and load (ETL) jobs several times a day.
A solutions architect needs to migrate this application to the AWS Cloud by designing an Amazon EMR cluster for the workload. The cluster must be available immediately to process jobs.
Which implementation meets these requirements MOST cost-effectively?

Answer options

• A. Use zonal Reserved Instances for the master nodes and the core nodes. Use a Spot Fleet for the task nodes.
• B. Use zonal Reserved Instances for the master nodes. Use Spot Instances for the core nodes and the task nodes.
• C. Use regional Reserved Instances for the master nodes. Use a Spot Fleet for the core nodes and the task nodes.
• D. Use regional Reserved Instances for the master nodes. Use On-Demand Capacity Reservations for the core nodes and the task nodes.

Correct answer: D

Explanation

To ensure the Amazon EMR cluster is immediately available to process jobs on demand without delays, On-Demand Capacity Reservations are required for the core and task nodes. Regional Reserved Instances for the master nodes provide cost-effective pricing with billing discounts. Options using Spot Instances or Spot Fleets cannot guarantee immediate availability, as Spot capacity can be terminated or unavailable when needed.