The answer is that the service account from Project A needs the Service Account User role (roles/iam.serviceAccountUser) on the Dataflow service account in Project B. This is required because when a Dataflow job is submitted to a target project, the job executes under the identity of a service account in that project, not the caller’s identity. The caller must have the `iam.serviceAccounts.actAs` permission on that target service account to delegate their authority; without it, the API call fails with a “dataflow cross project permission denied” error, even if the caller holds the Dataflow Developer role at the organization level. On the Google Professional Cloud Security Engineer exam, this scenario tests your understanding of the separation between job submission permissions and execution identity permissions—a common trap is assuming that broad roles like Dataflow Developer automatically grant cross-project `actAs` rights. Remember the memory tip: “Developer lets you submit, but Service Account User lets you act as.”
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 company uses multiple GCP projects and wants to allow a service account from Project A to initiate Dataflow jobs in Project B. The service account in Project A has the Dataflow Developer role at the organization level. However, it fails with permission denied when trying to submit a job to Project B. What is the most likely issue?
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.
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 the Service Account User role on the Dataflow service account in Project B.
The service account from Project A has the Dataflow Developer role at the organization level, which grants permissions to create Dataflow jobs, but it still needs the Service Account User role (roles/iam.serviceAccountUser) on the Dataflow service account in Project B. When a Dataflow job is submitted, the job runs as a service account in the target project (Project B), and the caller must have the iam.serviceAccounts.actAs permission on that service account. Without this role, the API call fails with a permission denied error even though the Dataflow Developer role is present.
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 organization policy restricts cross-project access.
Why it's wrong here
Organization policies would affect all projects, not just cross-project.
✗
The service account does not have permission to create Dataflow jobs in Project B because it is not a member of Project B.
Why it's wrong here
Organization-level roles grant access across all projects, so membership isn't the issue.
✗
The Dataflow API is not enabled in Project B.
Why it's wrong here
If the API were disabled, the error would be different.
✓
The service account needs the Service Account User role on the Dataflow service account in Project B.
Why this is correct
To act as the project's compute service account, the launching service account needs roles/iam.serviceAccountUser.
Clue confirmation
The clue word "most likely" 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 distinction between having a role that grants the ability to create a resource (like Dataflow Developer) versus the need for the Service Account User role to act as the service account that runs the resource, which is a subtle but critical IAM permission requirement.
Detailed technical explanation
How to think about this question
Under the hood, the Dataflow service uses a worker service account (often the Compute Engine default service account) to run the job's VMs and access resources. The actAs permission (iam.serviceAccounts.actAs) is required for the caller to impersonate that service account when submitting the job. This is enforced via the IAM condition that the caller must have the Service Account User role on the service account used by the Dataflow job. In real-world scenarios, this is a common misconfiguration when setting up cross-project Dataflow pipelines, as the Dataflow Developer role alone does not include the actAs permission.
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 company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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 the Service Account User role on the Dataflow service account in Project B. — The service account from Project A has the Dataflow Developer role at the organization level, which grants permissions to create Dataflow jobs, but it still needs the Service Account User role (roles/iam.serviceAccountUser) on the Dataflow service account in Project B. When a Dataflow job is submitted, the job runs as a service account in the target project (Project B), and the caller must have the iam.serviceAccounts.actAs permission on that service account. Without this role, the API call fails with a permission denied error even though the Dataflow Developer role is present.
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". 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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These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A Dataflow job launched by service account 'my-sa@...' fails with permission denied. The audit log shows the above entry. What missing role is causing the failure?
medium
A.roles/iam.workloadIdentityUser on the worker service account
✓ B.roles/iam.serviceAccountUser on the worker service account
C.roles/iam.serviceAccountAdmin on the worker service account
D.roles/iam.serviceAccountTokenCreator on the worker service account
Why B: When a Dataflow job fails with permission denied and the audit log shows the entry, the missing role is typically roles/iam.serviceAccountUser on the worker service account. This role is required because the Dataflow service (or the service account launching the job) must be able to impersonate the worker service account to execute the pipeline's tasks. Without this role, the job cannot assume the identity of the worker service account, leading to the permission denied error.
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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.
Question Discussion
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