- A
The service account needs roles/artifactregistry.reader on the repository.
Why wrong: Option A is incorrect; roles/artifactregistry.writer already includes the reader permission, so no additional reader role is needed.
- B
The service account needs roles/storage.objectViewer on the bucket where images are cached.
Why wrong: Option C is incorrect; Artifact Registry does not use a separate storage bucket for caching; the error indicates a permission issue with the registry itself.
- C
The service account needs roles/container.clusterAdmin on the cluster.
Why wrong: Option D is incorrect; clusterAdmin is a broad role not needed for image pulling, and the deployment succeeded, so the service account already has enough permissions for deployment.
- D
The service account needs roles/iam.serviceAccountUser on the GKE node service account.
Option B is correct; with Workload Identity, the pod's Kubernetes service account (typically the default) maps to the node service account. Granting the Cloud Build service account the serviceAccountUser role on the node service account allows impersonation for pulling images.
Quick Answer
The answer is that the Cloud Build service account requires the `roles/iam.serviceAccountUser` role on the GKE node’s Compute Engine service account. This is because, with Workload Identity enabled, the node’s service account—not the Cloud Build service account—authenticates to Artifact Registry when pods pull images. Without this impersonation permission, the Cloud Build service account cannot delegate its identity to the node’s service account, causing the `PermissionDenied` error despite the deployment step succeeding. On the Google Professional Cloud Security Engineer exam, this scenario tests your understanding of how Workload Identity decouples pod identity from the underlying node’s scopes; a common trap is assuming the Cloud Build service account’s `roles/artifactregistry.writer` is sufficient for image pulls, when in fact the node’s service account needs explicit `roles/artifactregistry.reader` and the Cloud Build account needs `iam.serviceAccountUser` to enable the impersonation chain. Memory tip: “Build writes, node reads—impersonation bridges the deeds.”
PCSE Practice Question: Configuring access within a cloud solution environment
This PCSE practice question tests your understanding of configuring access within a cloud solution environment. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 multinational corporation is implementing a least-privilege access model for their CI/CD pipeline using Cloud Build, Artifact Registry, and GKE. The pipeline builds container images, pushes them to Artifact Registry, and deploys them to GKE clusters. The security team wants to ensure that the Cloud Build service account used by the pipeline has only the minimum necessary permissions. The service account currently has: roles/cloudbuild.builds.editor, roles/artifactregistry.writer, and roles/container.developer. After a successful build and push, the deployment step completes without errors, but the newly deployed pods on GKE immediately fail with ImagePullBackOff errors. The error message indicates: "Failed to pull image 'us-central1-docker.pkg.dev/my-project/my-repo/my-image:latest': rpc error: code = PermissionDenied desc = unauthenticated: Request had insufficient authentication scopes." The GKE cluster is a private cluster with Workload Identity enabled. The node pool uses a default Compute Engine service account with only the storage scope. What is the most likely missing permission or configuration that prevents the pods from pulling images?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Clue:
"least"Why it matters: You want the option with minimum overhead, fewest steps, or lowest impact — not the most feature-rich or comprehensive answer.
Clue:
"minimum / minimize"Why it matters: Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
Clue:
"immediately / without restart"Why it matters: Time or reboot constraint — the correct answer must take effect right away without requiring a reboot or reload.
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
The service account needs roles/iam.serviceAccountUser on the GKE node service account.
Option D is correct because the Cloud Build service account needs the `roles/iam.serviceAccountUser` permission on the GKE node's Compute Engine service account to impersonate it. With Workload Identity enabled, the GKE node's service account (not the Cloud Build service account) is what authenticates to Artifact Registry when pods pull images. Without this delegation, the Cloud Build service account cannot act on behalf of the node's service account, leading to the `PermissionDenied` error.
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.
- ✗
The service account needs roles/artifactregistry.reader on the repository.
Why it's wrong here
Option A is incorrect; roles/artifactregistry.writer already includes the reader permission, so no additional reader role is needed.
- ✗
The service account needs roles/storage.objectViewer on the bucket where images are cached.
Why it's wrong here
Option C is incorrect; Artifact Registry does not use a separate storage bucket for caching; the error indicates a permission issue with the registry itself.
- ✗
The service account needs roles/container.clusterAdmin on the cluster.
Why it's wrong here
Option D is incorrect; clusterAdmin is a broad role not needed for image pulling, and the deployment succeeded, so the service account already has enough permissions for deployment.
- ✓
The service account needs roles/iam.serviceAccountUser on the GKE node service account.
Why this is correct
Option B is correct; with Workload Identity, the pod's Kubernetes service account (typically the default) maps to the node service account. Granting the Cloud Build service account the serviceAccountUser role on the node service account allows impersonation for pulling images.
Clue confirmation
The clue words "most likely", "least", "minimum / minimize", "immediately / without restart" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the misconception that the Cloud Build service account itself needs Artifact Registry read permissions, when in reality the node's service account must have those permissions and the Cloud Build service account needs the `iam.serviceAccountUser` role to impersonate it.
Detailed technical explanation
How to think about this question
Workload Identity in GKE allows pods to use a Kubernetes service account that is bound to a Google service account (GSA). When a pod tries to pull an image from Artifact Registry, the GKE node's GSA must have `roles/artifactregistry.reader` on the repository. The Cloud Build service account must have `roles/iam.serviceAccountUser` on the node's GSA to create tokens for the deployment step, enabling the node to authenticate. Without this, the node's default GSA (with only storage scope) cannot authenticate to Artifact Registry, causing the `ImagePullBackOff`.
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
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this PCSE question test?
Configuring access within a cloud solution environment — This question tests Configuring access within a cloud solution environment — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The service account needs roles/iam.serviceAccountUser on the GKE node service account. — Option D is correct because the Cloud Build service account needs the `roles/iam.serviceAccountUser` permission on the GKE node's Compute Engine service account to impersonate it. With Workload Identity enabled, the GKE node's service account (not the Cloud Build service account) is what authenticates to Artifact Registry when pods pull images. Without this delegation, the Cloud Build service account cannot act on behalf of the node's service account, leading to the `PermissionDenied` error.
What should I do if I get this PCSE question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely", "least", "minimum / minimize", "immediately / without restart". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jun 30, 2026
This PCSE 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 PCSE exam.
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