AWS Certified DevOps Engineer – ProfessionalResilient Cloud SolutionsEasy
A company uses a fleet of Amazon EC2 instances to run a batch processing application. This application is designed to be fault-tolerant, meaning individual instance failures do not affect the overall job completion. The company wants to minimize costs while ensuring that enough capacity is available to process jobs within a given timeframe. The workload can tolerate occasional interruptions. Which EC2 purchasing option is most cost-effective for this scenario?
- ADedicated Hosts.
- BReserved Instances.
- COn-Demand Instances.
- DSpot Instances.
Show answer & explanationAnswer & explanation
Correct answer: D. Spot Instances.
Spot Instances allow you to bid on unused EC2 capacity, offering significant cost savings (up to 90% off On-Demand prices). They are ideal for fault-tolerant, flexible workloads like batch processing that can tolerate interruptions, as AWS can reclaim Spot Instances with a 2-minute notification. This perfectly aligns with the goal of minimizing costs for a tolerant workload.
Why the other options are wrong
- A. Dedicated Hosts provide dedicated physical servers for licensing and compliance, which is overly expensive and unnecessary for this use case.
- B. Reserved Instances offer discounts for sustained, predictable workloads, not for flexible, interruptible batch processing.
- C. On-Demand instances are expensive and do not offer cost savings for interruptible workloads.
Amazon EC2 Spot Instances
Unused EC2 capacity available at a discounted price, ideal for fault-tolerant, flexible applications that can handle interruptions.
- Up to 90% cost savings compared to On-Demand.
- Instances can be interrupted by AWS with a 2-minute notice.
- Best for batch jobs, big data, CI/CD, and other stateless workloads.
Memory trick: Spot instances: Save substantially, sacrifice stability.