Google PCA Practice Question: Managing and Provisioning a Solution Infrastructure
Which GCP service should be used to automatically scale a GKE cluster's number of nodes based on pending pods?
⚠ Common exam trap
PCA often tests the confusion between HPA (scales pods), VPA (scales pod resources), and Cluster Autoscaler (scales nodes) — candidates who see 'pending pods' and pick HPA miss that HPA cannot help when there is no node capacity to schedule onto.
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
✓
Cluster Autoscaler
The GKE Cluster Autoscaler watches for pods that cannot be scheduled due to insufficient node capacity and automatically adds nodes to the node pool (and removes underutilized nodes). This is exactly the behavior described — scaling the cluster's node count based on pending pods.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Vertical Pod Autoscaler (VPA)
Why it's wrong here
VPA adjusts individual pod CPU and memory requests and limits; it never changes the node count, so pending pods stay pending. It is tempting because it is an autoscaler, but it operates on the pod resource axis, whereas scaling nodes for pending pods requires the Cluster Autoscaler.
- ✓
Cluster Autoscaler
Why this is correct
Cluster Autoscaler adds or removes nodes in a GKE node pool when pods remain pending due to insufficient allocatable resources, directly satisfying the stem's requirement to scale node count from pending pods. It watches the scheduler's unschedulable queue, unlike Horizontal Pod Autoscaler, which only adjusts replica counts of workloads.
- ✗
Node Auto-Provisioning
Why it's wrong here
Node Auto-Provisioning creates new node pools when pods cannot be scheduled, but it does not scale the number of nodes within an existing managed node pool. It is tempting as a scheduling remedy, yet the question asks for node-count scaling, which is the Cluster Autoscaler's function.
- ✗
Horizontal Pod Autoscaler (HPA)
Why it's wrong here
HPA scales the number of pod replicas in a workload based on metrics such as CPU utilisation; it never adds or removes nodes, so pending pods remain unscheduled. It is tempting because it is the best-known autoscaler, but node-count scaling for pending pods is the Cluster Autoscaler's role.
Go deeper
Related to this question
Learn chapter
IAM Policies, Service Accounts, and Auditing
Key term
Autoscaler
An Autoscaler is a cloud service that automatically increases or decreases the number of virtual machines (instances) or resources based on real-time demand, so your application always has enough capacity without wasting money on idle servers.
Key term
Node pool
A node pool is a group of virtual machines (nodes) within a container orchestration cluster that share the same configuration, such as machine size, operating system, and scaling settings, allowing you to manage them as a single unit.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Google Cloud exam blueprint
This PCA 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 PCA exam.