- A
Upgrade the existing VM to a larger machine type (vertical scaling).
Why wrong: Vertical scaling has a ceiling and requires downtime. Horizontal scaling with MIGs is more resilient and scalable.
- B
Create a Managed Instance Group from the VM and configure autoscaling with a load balancer.
A MIG with autoscaling adds VM instances on demand. A load balancer distributes incoming requests across all instances, providing true horizontal scalability.
- C
Add more persistent disks to the existing VM to handle more I/O.
Why wrong: Additional persistent disks improve I/O throughput, not compute or network capacity. The bottleneck is the single VM's CPU/memory, not disk I/O.
- D
Enable live migration on the existing VM so it can move between hosts.
Why wrong: Live migration moves a VM between physical hosts for maintenance purposes — it has no effect on scalability or traffic distribution.
Quick Answer
The answer is to create a Managed Instance Group from the VM and configure autoscaling with a load balancer. This is correct because horizontal scaling of stateless Compute Engine VM with managed instance group directly resolves a read-heavy bottleneck by distributing incoming traffic across multiple identical instances, with the load balancer acting as the single entry point and the MIG automatically adding or removing VMs based on demand. Since the application is stateless, no data synchronization is needed between instances, making this the most immediate and cost-effective scalability solution. On the Google Associate Cloud Engineer exam, this scenario tests your understanding that stateless applications are ideal for MIGs with autoscaling, while persistent disks or vertical scaling would not provide horizontal elasticity. A common trap is choosing to simply increase the machine type, but that is vertical scaling and does not improve fault tolerance or handle traffic spikes as effectively. Memory tip: Stateless + Read-heavy = MIG + Load Balancer.
Google ACE Planning and configuring a cloud solution Practice Question
This ACE practice question tests your understanding of planning and configuring a cloud solution. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company's application currently runs on a single Compute Engine VM with a persistent disk. The application serves read-heavy traffic and the single VM is becoming a bottleneck. The application is stateless. Which change provides the most immediate horizontal scalability improvement?
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
Create a Managed Instance Group from the VM and configure autoscaling with a load balancer.
Option B is correct because creating a Managed Instance Group (MIG) from the existing VM and configuring autoscaling with a load balancer directly addresses the read-heavy, stateless bottleneck by distributing traffic across multiple VM instances. This provides immediate horizontal scalability, as new instances are automatically provisioned or terminated based on load, without requiring any application changes.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Upgrade the existing VM to a larger machine type (vertical scaling).
Why it's wrong here
Vertical scaling has a ceiling and requires downtime. Horizontal scaling with MIGs is more resilient and scalable.
- ✓
Create a Managed Instance Group from the VM and configure autoscaling with a load balancer.
Why this is correct
A MIG with autoscaling adds VM instances on demand. A load balancer distributes incoming requests across all instances, providing true horizontal scalability.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Add more persistent disks to the existing VM to handle more I/O.
Why it's wrong here
Additional persistent disks improve I/O throughput, not compute or network capacity. The bottleneck is the single VM's CPU/memory, not disk I/O.
- ✗
Enable live migration on the existing VM so it can move between hosts.
Why it's wrong here
Live migration moves a VM between physical hosts for maintenance purposes — it has no effect on scalability or traffic distribution.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse vertical scaling (Option A) with horizontal scaling, or think that adding more disks (Option C) or enabling live migration (Option D) can solve a compute bottleneck, when only distributing the load across multiple instances (Option B) provides true horizontal scalability.
Detailed technical explanation
How to think about this question
Under the hood, a MIG uses instance templates to create identical VMs, and when paired with an HTTP(S) load balancer, it distributes incoming requests using Google Front End (GFE) and Maglev hashing for session affinity. Autoscaling policies can be based on CPU utilization, request count per second, or custom Stackdriver metrics, allowing the group to scale out in minutes. A real-world scenario where this matters is a flash sale: without a MIG, a single VM would be overwhelmed, but with autoscaling, new instances spin up to handle the spike and scale down afterward, optimizing cost.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this ACE question test?
Planning and configuring a cloud solution — This question tests Planning and configuring a cloud solution — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Create a Managed Instance Group from the VM and configure autoscaling with a load balancer. — Option B is correct because creating a Managed Instance Group (MIG) from the existing VM and configuring autoscaling with a load balancer directly addresses the read-heavy, stateless bottleneck by distributing traffic across multiple VM instances. This provides immediate horizontal scalability, as new instances are automatically provisioned or terminated based on load, without requiring any application changes.
What should I do if I get this ACE question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 11, 2026
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.
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