Which solution will meet these requirements MOST cost-effectively?
Use Reserved Instances for the frontend nodes. Use AWS Fargate for the backend nodes.
Use Reserved Instances for the frontend nodes. Use Spot Instances for the backend nodes.
Use Spot Instances for the frontend nodes. Use Reserved Instances for the backend nodes.
Use Spot Instances for the frontend nodes. Use AWS Fargate for the backend nodes.
Explanations:
While using Reserved Instances for frontend nodes is a cost-effective choice, AWS Fargate may not be the best option for backend nodes that vary in number and run only for short periods, as it can be more expensive than other options like Spot Instances when scaling.
This option combines the cost savings of Reserved Instances for the consistently running frontend nodes with Spot Instances for the variable backend nodes, which can significantly reduce costs during periods of low workload.
Using Spot Instances for the frontend nodes is not advisable since they can be interrupted, leading to downtime for a service that needs to run 24/7. Reserved Instances would be a better choice for reliability in this case.
Similar to option C, using Spot Instances for the frontend nodes is not reliable for an application that needs to run continuously. AWS Fargate may also not be cost-effective for varying backend workloads compared to Spot Instances.
I organize that the answer is:
Use Reserved Instances for the frontend nodes. Use Spot Instances for the backend nodes.