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Difficulty: HardAWS Pricing Models

A logistics enterprise is deploying a containerized delivery route optimization application on Amazon EC2. The workload consists of three distinct components:

1. A fleet of background worker instances that run continuously 24/7 to process incoming telemetry data, where the core compute requirement is highly stable and predictable.
2. A scaling group of instances that dynamically scales out to handle sudden, unpredictable spikes in user traffic during holiday shopping events, which must be served immediately and cannot tolerate interruptions.
3. A set of batch jobs that run nightly to calculate historical route efficiencies; these jobs are stateless, fault-tolerant, and can be stopped and restarted without impacting business operations.

Which combination of Amazon EC2 pricing models provides the most cost-optimized solution for these three workloads?

  1. A
    Spot Instances for the background worker fleet, On-Demand Instances for the scaling group handling unpredictable spikes, and Savings Plans for the nightly batch jobs.
  2. B
    Savings Plans for the background worker fleet, Spot Instances for the scaling group handling unpredictable spikes, and On-Demand Instances for the nightly batch jobs.
  3. Savings Plans for the background worker fleet, On-Demand Instances for the scaling group handling unpredictable spikes, and Spot Instances for the nightly batch jobs.Answer
  4. D
    Dedicated Hosts paid upfront for all three workloads to maximize capital expenditure (CapEx) tax benefits and guarantee physical isolation.

Answer

Savings Plans for the background worker fleet, On-Demand Instances for the scaling group handling unpredictable spikes, and Spot Instances for the nightly batch jobs.
The correct option maps each workload to its most cost-optimized pricing model. Continuous 24/7 background workers with stable requirements benefit from Savings Plans. The unpredictable spikes in user traffic are served by On-Demand Instances to ensure service reliability, and the fault-tolerant nightly batch jobs are run on Spot Instances to achieve maximum cost savings.

Step-by-Step Solution

1
Evaluate the 24/7 background worker fleet workload.
Identified as a steady-state, predictable workload running continuously.
Workloads with stable usage are best covered by commitment-based models like Savings Plans or Reserved Instances to secure deep discounts.
2
Evaluate the scaling group for unpredictable spikes.
Identified as an unpredictable workload that must be served immediately and cannot tolerate interruptions.
On-Demand Instances are required because they guarantee availability and prevent interruptions, and commitment models are not cost-effective for short, unpredictable spikes.
3
Evaluate the nightly batch jobs.
Identified as a stateless, fault-tolerant, and non-time-critical workload.
Spot Instances are ideal for workloads that can handle interruptions because they offer the lowest cost (up to 90% off On-Demand rates).
4
Synthesize the individual workloads into a unified pricing strategy.
The optimal combination is Savings Plans for the baseline, On-Demand for scaling spikes, and Spot for batch jobs.
This combination minimizes costs while meeting all operational constraints and reliability requirements.

Key Concept

AWS EC2 pricing models selection based on predictability, interruption tolerance, and flexibility.
Estimated Time:2m 0s
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Topics

AWS Pricing Models

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