easyMultiple ChoiceObjective-mapped
Google ACE Practice Question: A batch data processing job runs nightly for 4…
A batch data processing job runs nightly for 4 hours and can tolerate interruption because it saves progress checkpoints every 15 minutes. Which VM option offers the greatest cost reduction?
⚠ Common exam trap
Google Cloud often tests the misconception that custom machine types or sole-tenant nodes are cost-saving options, but the trap here is that Spot VMs are the only option that directly leverages preemptible pricing for interruptible workloads, while other options either increase cost or provide no cost benefit.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Spot VM
Spot VMs offer significant cost reduction (up to 60-91% discount) compared to standard VMs, making them ideal for fault-tolerant, interruptible batch workloads. Since the job saves checkpoints every 15 minutes, it can resume from the last checkpoint if preempted, fully leveraging the cost benefit of Spot VMs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Custom machine type VM with reduced memory
Why it's wrong here
Custom machine types let you tailor vCPU and memory to the exact needs of your workload, which can avoid overprovisioning and lower the per-hour cost compared to predefined machine types. However, you are still paying the standard on-demand price for the resources you allocate, with no special interruption tolerance or bulk discount. The modest savings from reducing memory are far less than the typical 60–91% discount offered by Spot VMs, making this an insufficient cost optimization for a large batch workload.
- ✓
Spot VM
Why this is correct
Spot VMs are Compute Engine instances that run on excess, unused capacity at a steep discount, often up to 91% compared to standard VM pricing. They are ideal for batch jobs that can tolerate interruption because Compute Engine can preempt a Spot VM with only 30 seconds' notice, so the workload must implement checkpointing or divide work into small restartable tasks. For a data processing batch job that is non-urgent and fault-tolerant, Spot VMs provide the greatest cost reduction while maintaining acceptable reliability.
- ✗
Sole-tenant node VM
Why it's wrong here
Sole-tenant node VMs are dedicated physical servers that isolate your workloads from other customers' VMs on the same host, which is required for certain compliance, regulatory, or licensing scenarios. This isolation comes at a premium: you pay for the entire sole-tenant node regardless of how many VMs run on it, making it significantly more expensive than standard or Spot VMs. It is the opposite of a cost-saving measure and is not appropriate for a batch workload whose main goal is minimizing cost.
- ✗
Shielded VM
Why it's wrong here
Shielded VMs are a security configuration, not a pricing model. They enable Secure Boot, virtual trusted platform module (vTPM), and integrity monitoring to protect against rootkits and boot-level attacks, but they are billed at standard Compute Engine rates with no discount. Selecting a Shielded VM may even incur additional costs for vTPM-related features in some environments, so it cannot reduce the total spend for a large batch job.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This ACE practice question is part of Courseiva's free Google Cloud certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the ACE exam.