Cloud Digital Leader Fundamental Cloud Concepts Practice Question
An organization wants to use Google Cloud to analyze large-scale genomic data. The data is stored in Cloud Storage in a compressed format. They need to run a custom Python pipeline that preprocesses the data and then uses a GPU-intensive algorithm for alignment. The preprocessing is CPU-bound and takes 30 minutes per sample, while the alignment takes 1 hour per sample on a GPU. They have thousands of samples. Which compute approach is MOST cost-effective?
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
✓
Use preemptible VMs with CPU for preprocessing and preemptible VMs with GPU for alignment, with checkpointing
Using preemptible VMs for both steps can significantly reduce costs, especially for large batches. However, GPU preemptible pricing is also lower. The workload is batch and fault-tolerant if checkpointing is implemented. Committed use discounts require 1-year commitment; sole-tenant nodes are for isolation; independent scaling of CPU and GPU is not directly available without separate instance groups.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use committed use discounts for 1 year on GPU instances
Why it's wrong here
Committed use discounts (CUDs) require a 1- or 3-year commitment and are designed for steady-state, always-on workloads. For a finite batch analysis job that will finish and shut down, you would continue paying for reserved GPU capacity even after the workload completes, and you forfeit the 60-80% savings offered by preemptible VMs. Since the workload is transient, the long-term commitment makes CUDs economically suboptimal here.
- ✗
Use regular VMs with both CPU and GPU on the same instance
Why it's wrong here
Using a single regular VM with both CPU and GPU forces you to provision a fixed-size instance that must accommodate both phases, but during CPU-heavy preprocessing the GPU remains idle and during GPU-heavy alignment the CPU is underutilized. These instances are billed per second at on-demand rates, which can be several times higher than preemptible pricing. A design that separates preprocessing and alignment into distinct autoscaling VM pools lets each resource scale independently and eliminates paying for idle components.
- ✓
Use preemptible VMs with CPU for preprocessing and preemptible VMs with GPU for alignment, with checkpointing
Why this is correct
Preemptible VMs cost up to 70-80% less than standard VMs and are killed by Google Compute Engine within 24 hours, making them ideal for fault-tolerant batch tasks. By splitting the pipeline into CPU-based preprocessing and GPU-based alignment on separate preemptible VM groups, you avoid mixing resource types and can automatically restart interrupted tasks from checkpointed state. This minimizes compute spend while still completing the analysis, and is the most cost-effective approach for a finite workload.
- ✗
Use sole-tenant nodes for data isolation
Why it's wrong here
Sole-tenant nodes lock a physical server to your project and are typically used to satisfy licensing or regulatory isolation requirements, not to reduce costs. You pay for the entire node, regardless of how many of its vCPUs or GPUs you actually use, and they do not support preemptible pricing or per-second billing at reduced rates. For a data analysis job that simply needs cheap, interruptible compute, sole-tenant nodes would be significantly more expensive without providing any processing benefit.
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Related to this question
Learn chapter
Cloud Digital Transformation
Key term
Data
Data is raw, unprocessed information, like numbers, words, or measurements, that can be stored, processed, and analyzed by computers.
Key term
Organization
An Organization is a top-level container in Google Cloud that represents your company or entities and serves as the root node for all your cloud resources, policies, and access control.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This GCDL 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 GCDL exam.