Cloud Digital Leader Scaling with Google Cloud operations Practice Question

A company runs a web application on Compute Engine. During seasonal sales, traffic spikes unpredictably. The operations team wants to ensure the application scales automatically without manual intervention while minimizing cost. Which solution should they implement?

⚠ Common exam trap

Google Cloud often tests the distinction between horizontal and vertical scaling, where candidates mistakenly choose vertical scaling (Option D) because they think a larger VM is simpler, but they overlook the downtime, hard limits, and lack of elasticity required for unpredictable traffic spikes.

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 a managed instance group with autoscaling based on CPU utilization.

A managed instance group (MIG) with autoscaling based on CPU utilization is the correct solution because it automatically adjusts the number of VM instances in response to real-time traffic spikes, ensuring the application scales out during high demand and scales in during low demand. This eliminates manual intervention and optimizes cost by only running the necessary number of instances based on a target CPU utilization threshold (e.g., 60-80%).

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
Create a managed instance group with a fixed number of instances.
Why it's wrong here
A managed instance group (MIG) with a fixed number of instances lacks elasticity: it cannot automatically adjust capacity in response to demand. During traffic spikes, the fixed pool becomes under-provisioned, causing slowdowns or dropped requests, while during low demand it remains over-provisioned, wasting money. This static approach provides no dynamic scaling and fails to match cost to actual workload.
✗
Use an unmanaged instance group and manually add instances.
Why it's wrong here
An unmanaged instance group with manual instance addition requires human intervention to react to load changes. Detecting rising CPU utilization and then manually provisioning or terminating VMs is slow and error-prone, so the application can suffer from poor responsiveness during sudden spikes. This approach does not provide automated, real-time capacity management, which is essential for unpredictable workloads.
✓
Use a managed instance group with autoscaling based on CPU utilization.
Why this is correct
A managed instance group with autoscaling based on CPU utilization automatically adjusts the number of VM instances to match current demand. The autoscaler adds instances when average CPU utilization exceeds a target threshold, and removes instances when utilization drops, providing elastic horizontal scaling. This yields both high availability under spikes and cost efficiency during low usage, all without manual intervention.
✗
Use a single large VM with vertical scaling.
Why it's wrong here
Using a single large VM with vertical scaling relies on increasing the machine type, but a VM has a hard upper limit on CPU, memory, and network capacity. Once that limit is reached, you cannot scale further, and resizing a single VM typically requires a reboot, causing downtime. This design also creates a single point of failure, whereas horizontal scaling across multiple instances offers better resilience and near-limitless growth.

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Cloud Digital Leader Scaling with Google Cloud operations Practice Question

Why each option matters

Option-by-option breakdown

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