Which combination of actions will be MOST cost-effective?
(Choose two.)
Use Dedicated Hosts for the control nodes.
Use Reserved Instances for the control nodes.
Use Reserved Instances for the worker nodes.
Use Spot Instances for the control nodes and On-Demand Instances if there is no Spot availability.
Use Spot Instances for the worker nodes and On-Demand Instances if there is no Spot availability.
Explanations:
Dedicated Hosts are typically used for compliance or licensing requirements and would not provide a significant cost advantage for control nodes, which run continuously.
Reserved Instances for the control nodes would provide cost savings since they are running continuously, typically offering a discount compared to On-Demand pricing.
Reserved Instances for worker nodes are not ideal since worker nodes are used only 4 hours a day. Reserved Instances lock in a long-term commitment and wouldn’t offer significant savings for short-term usage.
Spot Instances for control nodes are not ideal because control nodes are likely critical and require availability. Spot Instances can be terminated by the provider, which can lead to service disruptions.
Spot Instances for worker nodes are cost-effective since worker nodes are used intermittently (4 hours daily) and can tolerate interruptions. If Spot Instances are unavailable, On-Demand Instances can be used.
I sort that the answer is:
Use Reserved Instances for the control nodes.