Exam AWS Certified Cloud Practitioner topic 1 question 10 discussion

Who's providing the "correct" answer here? Answers should all be reviewed, you're confusing the examinees. C should be the answer.

C is the correct answer, the question explicitly mentioned that "The application cannot sustain any interruption" of which Spot Instances are ideal for workloads with flexible start and end times, or that can withstand interruptions. Ideally we want pricing that doesn't allow interruption in this case it will be On-Demand.

Option C. Reserved Instances provide cost savings for the predictable baseline usage. On-Demand Instances, while more expensive than RIs, ensure availability for the seasonal spikes without long-term commitments. This combination ensures no interruptions while balancing cost and flexibility.

Buy Reserved Instances for the predicted amount of usage throughout the year. Allow any seasonal usage to run at an On-Demand rate.

Correct answer is C on-demand: No interruptions spot Instance: Slight risk of interruptions

The correct answer is B. To answer an AWS exams correctly, always find the keyword(s). The answer cannot be B because of the keywords there is "The application cannot sustain any interruption." Reserved Instances (RIs) are ideal for workloads with predictable usage because they offer significant savings compared to On-Demand rates. Since the seasonal spikes last only a few weeks, running them at the On-Demand rate would be more flexible and cost-effective than over-provisioning RIs for the whole Though spot instances are cheaper, they are meant for applications that can withstand interruptions, that cancels B. Option C, on the other hand provides a balance between cost savings and maintaining uninterrupted service.

The most cost-effective option for this scenario is C. Here's why: Reserved Instances (RIs) are typically used for predictable workloads, offering significant discounts over On-Demand pricing. Buying RIs for the year-round predictable usage ensures cost savings. On-Demand Instances for the seasonal spikes allow flexibility during peak periods without having to commit to paying for capacity that isn't needed for the rest of the year. Although On-Demand rates are higher than Reserved Instances, they avoid unnecessary upfront costs for periods when the application doesn’t need extra capacity.

The correct answer is B. If you refer back to the course and listen again to the videos with the coffee shop example you will hear that B is the correct answer to this case scenario. When the reserved instances meet spikes the AWS autoscale will indeed add spot instances ( to work on the spot ) and cover the spike so that everything is scaled and the services keep running with no delays ( that Spot instance payment will be similar to the On demand instance type payment ) , On-Demand in AWS services does not mean that an instance is launched on demand, it simply is a referral to an intsance type that is launched already which you pay for as you go, which means that you only pay for the demanded capacity used. Please feel free to correct me if i am wrong

The question have a phrase which states the following "The application cannot sustain any interruption." Meaning if the application was going to sustain interpretation option B would be stand a chance to be an option as the answer. Now option B is not a choice at all. Correct Answer is C.

C is correct

why is it not A?

Its definitely C as the correct answer. Spot instance is clearly in the textbook that has uncontrolled interruptions within apps and services.

Reserved & Spot Instances-B

C Spot Instances could introduce interruptions, which is not acceptable for an application that cannot sustain any interruption.

Yes B, Spot Instance allow you to bidding over the available AWS computing resources and allow you to use computing resource over the period of time, it's suitable for spike demand which can be interrupted. If you won the bidding the computing power will be your over the time while you own it if other won the bidding, you resources from previous will be lost this is mean your App on EC2 instance will be stop and choose Spot Instance is not suite for this requirement.

B. Reserved & Spot Instances

Spot instances can only be used for applications with flexible start and end times, and fault tolerant applications. Both of these are not features of the application in the case study. https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/spot-best-practices.html