Exam AWS Certified Cloud Practitioner CLF-C02 topic 1 question 112 discussion

How do they expect me to buy their expensive subscription with so many -not even close- wrong answers...

Uninterruptible + Years = saving plans or reserved instances

The application can continue processing tasks with SQS. Therefore, even if the server goes down and then comes back up, it can retrieve the data to continue processing from SQS. Choosing a spot instance seems to be the right answer because spot instances are cheaper than using a saving plan.

C. AWS Savings Plan or Reserved Instances for a 1 to 3-year workload for cost-effective management

AWS Savings Plan or Reserved Instances for a 1 to 3-year workload for cost-effective management

Spot instances is wrong because they need uninterruptable need

C. Savings Plans Savings Plans provide significant cost savings compared to On-Demand Instances, while still offering flexibility and a commitment to a consistent amount of usage, which aligns with the long-term, predictable workload described in the scenario. This model allows you to commit to a consistent amount of usage (measured in dollars per hour) for a 1-year or 3-year term, offering flexibility across EC2 instance types, sizes, and regions. It's a suitable choice for workloads with sustained usage over a long period.

The application cannot be interrupted so it cannot do spot instances. The usage is not consistent because it is expected to grow so we cannot do savings plans. The only thing that makes sense is On-Demand Instances.

C = CORRECT

why it is not on-demand?

Answer: C A.Spot Instanc let you bid against unutilized instance in AWS.It's provide a cost-effective solution to but this instance can be terminated due while you process your workload.

The right answer is C, saving plan , spot instance is not the right answer because Spot Instances are typically terminated for capacity reasons, not due to individual instance failures. This means multiple instances could be interrupted simultaneously, potentially affecting the entire application. Even with diversification strategies like Spot Fleets, there's a chance of correlated interruptions across instances. And it’s for an uninterruptible application. Saving plan is the the right one!

How do they expect me to buy their expensive subscription with so many -not even close- wrong answers...

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The right answer is C, saving plan , spot instance is not the right answer because Spot Instances are typically terminated for capacity reasons, not due to individual instance failures. This means multiple instances could be interrupted simultaneously, potentially affecting the entire application. Even with diversification strategies like Spot Fleets, there's a chance of correlated interruptions across instances. And it’s for an uninterruptible application. Saving plan is the the right one!

Question text clearly indicates multiple EC2 instances for an application - Not a single instance so in a distributed nature there is a chance of implementing High availability. If SQS might not have mentioned in the question text I would have selected "Saving Plans" as answer. But having SQS and possibility to use auto scaling through multiple EC2 instances can make solution fault tolerant or highly available even if some EC2 instances may experience interruption i.e. Solution can remain uninterruptible. And hence I am choosing "A" as the answer. First link below explains this beautifully. https://aws.amazon.com/blogs/compute/running-cost-effective-queue-workers-with-amazon-sqs-and-amazon-ec2-spot-instances/ https://docs.aws.amazon.com/wellarchitected/latest/cost-optimization-pillar/select-the-best-pricing-model.html

The application is on different EC2 instances, and uses SQS, so it's a decoupled application, probably also distributed. SQS is asyncronous, and processing is batch, so it's ok to interrupt instances now and then if they are distributed in a reliable way on multiple regions for example. For me it's Spot Instances.