A company runs a production web application that uses Amazon EC2 instances, AWS Lambda functions, and Amazon ECS tasks. The application runs 24/7 and the company expects steady usage for the next three years. The company wants to commit to a flexible pricing model that provides significant discounts compared to On-Demand and automatically applies to usage across all three compute services. The company also wants the flexibility to change instance families, regions, or even migrate between compute services (e.g., from EC2 to Lambda) without needing to modify the commitment. Which AWS pricing model should the company choose?
Compute Savings Plans are the correct answer because they provide flexible, automatic discounts across Amazon EC2, AWS Lambda, and AWS Fargate usage. You commit to a consistent hourly spend for a 1- or 3-year term, but the plans apply to any instance family, size, or region, and even adapt to containers and serverless workloads without requiring any modifications to your running resources. This makes them ideal for production environments that need both cost savings and operational agility.
Why this answer
Compute Savings Plans offer the required flexibility: they automatically apply to EC2 instances, Lambda functions, and ECS Fargate usage, provide significant discounts (up to 66%) compared to On-Demand, and allow changes to instance families, regions, or compute services without modifying the commitment. This model is ideal for steady 24/7 workloads over a three-year term, as it combines broad compute coverage with automatic discount application.
Exam trap
The trap here is that candidates often confuse Compute Savings Plans with EC2 Instance Savings Plans, mistakenly thinking the latter also covers Lambda and ECS, but EC2 Instance Savings Plans are restricted to a specific instance family and region, and only apply to EC2 usage.
Why the other options are wrong
EC2 Reserved Instances (Standard) apply only to EC2 instances, not to Lambda or ECS usage, and do not allow changing instance families or regions without modification. The question requires a plan that covers all three compute services and allows flexibility across services, regions, and instance families.
Convertible RIs allow changing instance families but are tied to EC2 only, not Lambda or ECS, and require manual modification of the commitment, lacking the automatic cross-service coverage of Compute Savings Plans.
When would these options actually be correct?
A company runs only EC2 instances for a steady-state workload and wants the lowest possible cost with no need to change instance family, region, or compute service over the term. They are willing to commit to a specific instance configuration for 1 or 3 years.
A company runs only EC2 instances for a steady workload, wants flexibility to change instance families or regions, and is willing to accept a slightly lower discount than Standard RIs in exchange for that flexibility.
Why candidates pick the wrong answer
Candidates may think Reserved Instances are the standard way to get discounts for steady usage, overlooking that Savings Plans offer broader coverage and flexibility across multiple compute services.
Candidates may confuse 'Convertible' with the flexibility to change services, not realizing it still applies only to EC2, and may overlook that Savings Plans offer broader coverage with less management overhead.