PCD Building and testing applications Practice Question
This PCD practice question tests your understanding of building and testing applications. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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.
Network Topology
Refer to the exhibit. A developer deployed a Cloud Run service as shown. Authenticated requests from another service in the same project using a service account receive 403 Forbidden. What is the most likely cause?
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 used to authenticate is not granted the roles/run.invoker role on the Cloud Run service
Option C is correct because the Cloud Run service requires the IAM role `roles/run.invoker` on the service itself for any principal (including a service account) to invoke it. Since the service was deployed with `--no-allow-unauthenticated`, only explicitly granted principals can invoke it. The service account used for authentication lacks this role, causing the 403 Forbidden response.
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 Cloud Run service requires the 'allAuthenticatedUsers' member to be added
Why it's wrong here
That would allow any authenticated user; best practice is to grant only specific service accounts.
✗
The --no-allow-unauthenticated flag blocks all requests including authenticated ones
Why it's wrong here
It blocks unauthenticated requests; authenticated requests are allowed if IAM permits.
✓
The service account used to authenticate is not granted the roles/run.invoker role on the Cloud Run service
Why this is correct
The IAM policy must grant invoker role to the service account.
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.
✗
The container image was built without proper authentication headers
Why it's wrong here
Authentication headers are handled by the client, not the container.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that `--no-allow-unauthenticated` blocks all requests, including authenticated ones, when in reality it only blocks unauthenticated requests and requires explicit IAM role assignment for authenticated principals.
Detailed technical explanation
How to think about this question
Cloud Run uses Identity-Aware Proxy (IAP) and IAM to enforce access control. When `--no-allow-unauthenticated` is set, the Cloud Run service expects the incoming request to include an OAuth2 access token or identity token from a principal that has been granted the `roles/run.invoker` role on the service. The service account must be granted this role via `gcloud run services add-iam-policy-binding` or through the Google Cloud Console. Without this binding, even a valid token from that service account results in a 403 Forbidden because the IAM policy denies the invocation.
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.
Building and testing applications — This question tests Building and testing applications — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The service account used to authenticate is not granted the roles/run.invoker role on the Cloud Run service — Option C is correct because the Cloud Run service requires the IAM role `roles/run.invoker` on the service itself for any principal (including a service account) to invoke it. Since the service was deployed with `--no-allow-unauthenticated`, only explicitly granted principals can invoke it. The service account used for authentication lacks this role, causing the 403 Forbidden response.
What should I do if I get this PCD 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.
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This PCD 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 PCD exam.
Question Discussion
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