A media company processes a nightly video transcoding queue on a fleet of EC2 instances. Each job is short, fully stateless, and checkpoints its progress to Amazon S3, so any instance that disappears mid-job simply has its work resumed by another. The fleet can flex between many instance types and runs only when the queue is non-empty. The architect wants the lowest possible compute cost without committing to any fixed term. Which pricing model best fits this workload?
- AStandard Reserved Instances purchased for a one-year term against the most common instance type, accepting the term commitment to lock in the reservation discount on the fleet.
- BOn-Demand Instances run continuously so the queue is always drained immediately, paying the full hourly rate in exchange for never being interrupted by a capacity reclaim.
- CA one-year Compute Savings Plan sized to the average nightly throughput, committing to a steady hourly spend to discount the transcoding fleet across instance families.
- DSpot Instances drawn from several instance pools, letting the interruption-tolerant fleet reclaim and resume checkpointed jobs whenever capacity is reclaimed by AWS at short notice. Correct
Why A is wrong: Tempting because Reserved Instances cut cost on steady usage, but they require a one-year or three-year commitment and suit always-on baselines, not an interruption-tolerant fleet that runs only when work exists.
Why B is wrong: Tempting because On-Demand needs no commitment, but it charges the full rate and forgoes the deep discount this interruptible, checkpointing fleet is perfectly positioned to capture with Spot.
Why C is wrong: Tempting because Savings Plans discount flexible compute, but they demand a one-year or three-year hourly spend commitment that does not match a bursty queue, and the stem rules out any fixed term.
Why D is correct: Spot offers the deepest discount off On-Demand and is built for stateless, fault-tolerant, flexible workloads that checkpoint progress, so interruptions cost nothing beyond a resumed job.