Exam AWS Certified Cloud Practitioner CLF-C02 topic 1 question 33 discussion

B = Keyword is Fault Tolerant

fault tolerant = it can be interrupted then Spot instances is the right answer

B, because "Spot Instances are a cost-effective choice if you can be flexible about when your applications run and if your applications can be interrupted. For example, Spot Instances are well-suited for data analysis, batch jobs, background processing, and optional tasks. " https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-spot-instances.html

I think C should be the right answer - On-Demand Instances provide capacity on a pay-as-you-go basis with no upfront commitment. They are suitable for short-term, variable workloads, offering flexibility without the need for long-term commitments. In this scenario, On-Demand Instances would be a cost-effective option for the 2-month duration while avoiding downtime.

B = CORRECT

why B?

It says a thousand amount of simultaneous simulations

B. Spot Instances: Allow users to bid for unused EC2 capacity, potentially providing cost savings. They are suitable for workloads that are fault-tolerant and can handle interruptions. Spot Instances are a good fit for the described scenario of thousands of simultaneous simulations.

On-Demand Instance

Reserved Instances: While offering a significant discount compared to On-Demand Instances, they require a one-year or three-year commitment and upfront payment. This might not be ideal for workloads with variable demand or short durations like the given simulations. Spot Instances: These offer the potential for significant cost savings compared to On-Demand Instances, with prices fluctuating based on supply and demand. They are well-suited for stateless, fault-tolerant workloads like the company's simulations, as they can be automatically terminated and restarted on price spikes without impacting the overall execution. On-Demand Instances: These provide predictable pricing but are the most expensive option. Given the cost optimization goal and stateless nature of the simulations, Spot Instances offer a better cost-performance trade-off. Dedicated Instances: Similar to Reserved Instances, these come with an upfront commitment and fixed payments, making them less flexible for workloads with variable demand like the simulations.

A. Reserved Instances: Involve a commitment to a specific instance type in a particular region for a term of 1 or 3 years. They offer cost savings compared to On-Demand pricing, but may not be suitable for stateless and fault-tolerant workloads with short durations. B. Spot Instances: Allow users to bid for unused EC2 capacity, potentially providing cost savings. They are suitable for workloads that are fault-tolerant and can handle interruptions. Spot Instances are a good fit for the described scenario of thousands of simultaneous simulations. C. On-Demand Instances: Are charged at the regular, non-reserved pricing. They provide flexibility without any upfront commitments, but may not be the most cost-effective option. D. Dedicated Instances: Run on hardware dedicated to a single customer but do not provide significant cost optimization. They are more suitable for scenarios where regulatory or compliance requirements necessitate dedicated hardware.

https://aws.amazon.com/aws-cost-management/aws-cost-optimization/spot-instances/#:~:text=Amazon%20EC2%20Spot%20Instances%20let,applications%20running%20on%20Spot%20Instances.

B is incorrect. Spot Instances are a cost-effective choice if you can be flexible about when your applications run and if your applications can be interrupted.

B because of the fault tolerant

B. Spot Instances For stateless, fault-tolerant workloads that can handle interruptions and have short durations, using Spot Instances is a cost-effective option. Spot Instances allow you to bid for unused EC2 capacity at a potentially lower price than On-Demand Instances. However, Spot Instances can be terminated if the capacity is needed by On-Demand or Reserved Instances customers. Given the nature of the company's workload, where thousands of simulations are run simultaneously and each simulation is stateless, fault-tolerant, and runs for up to 3 hours, Spot Instances would be a suitable choice. This can help optimize costs by taking advantage of the lower pricing for unused capacity.

Answer B is Correct. Key: "Each simulation is stateless and is fault tolerant"

Spot Instances are a good fit for stateless, fault-tolerant workloads that can be interrupted without any impact on the overall job.