Which solution will meet these requirements MOST cost-effectively?
Purchase Reserved Instances for the jobs.
Submit a request for a one-time Spot Instance for the jobs.
Submit a request for Spot Instances with a defined duration for the jobs.
Use a mixture of On-Demand Instances and Spot Instances for the jobs.
Explanations:
Reserved Instances are intended for long-term, steady-state usage and require a commitment for 1 or 3 years. This would not be cost-effective for jobs that can run at any time and may not need consistent capacity.
A one-time Spot Instance would not guarantee completion of the job if the instance is terminated. Spot Instances can be interrupted, which means the job would have to restart from the beginning, leading to potential inefficiencies.
Spot Instances with a defined duration are ideal because they provide a cost-saving option and are guaranteed to run for the specified duration. If a job requires just under 2 hours and can handle interruptions, this would be the most cost-effective and reliable solution.
Mixing On-Demand Instances with Spot Instances introduces unpredictability in terms of instance availability. While Spot Instances may save cost, the use of On-Demand Instances would reduce cost savings overall, and Spot Instances may still be interrupted, requiring job restarts.
I reckon the answer is:
Submit a request for Spot Instances with a defined duration for the jobs.