The answer is that the Cloud Run service account lacks the Cloud SQL Client role. This IAM permission is required because Cloud Run uses its service account identity to authorize connections to Cloud SQL; without the roles/cloudsql.client role, the connection attempt is denied, producing the "permission denied" error in the logs. On the Google Professional Cloud Developer exam, this scenario tests your understanding of how IAM roles govern service-to-service communication, often appearing as a trap where candidates mistakenly focus on network configurations or database credentials instead of the missing role. A common memory tip is to remember that Cloud SQL Client is the "key" for Cloud Run to unlock the database—without it, even correct network settings and valid credentials will fail.
PCD Integrating Google Cloud services Practice Question
This PCD practice question tests your understanding of integrating google cloud services. 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.
Refer to the exhibit. A Cloud Run service is unable to connect to a Cloud SQL instance. The log entry shows the following. 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 Cloud Run service account lacks the Cloud SQL Client role.
The Cloud Run service needs the Cloud SQL Client role (roles/cloudsql.client) on its service account to authorize connections to Cloud SQL. Without this IAM permission, the connection attempt is denied, resulting in the 'unable to connect' error shown in the log. This is the most common cause of connectivity failures between Cloud Run and Cloud SQL.
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 account lacks the Cloud SQL Client role.
Why this is correct
Without the cloudsql.client role, the VPC connector cannot authorize the connection, leading to a connection refused error.
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 database user credentials are incorrect.
Why it's wrong here
Incorrect credentials result in an authentication error, not a connection refused at the network level.
✗
The Cloud SQL instance is in a different region than the Cloud Run service.
Why it's wrong here
Cross-region connections are possible; the error would typically be a timeout, not a connection refused.
✗
The Cloud SQL instance has a public IP assigned.
Why it's wrong here
A public IP would not cause a connection refused by itself; the service would still try to connect, and if allowed, it would succeed.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that database credentials (Option B) are the primary cause of Cloud Run-to-Cloud SQL failures, but the actual issue is almost always missing IAM permissions on the service account.
Detailed technical explanation
How to think about this question
Under the hood, Cloud Run uses the Cloud SQL Auth Proxy to establish an encrypted connection to Cloud SQL. The proxy authenticates using the Cloud Run service account's IAM role; without the Cloud SQL Client role, the proxy cannot obtain a temporary token to connect. In a real-world scenario, if you migrate a Cloud Run service to a new project, forgetting to grant the Cloud SQL Client role on the new service account is a common oversight that breaks connectivity.
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.
Integrating Google Cloud services — This question tests Integrating Google Cloud services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The Cloud Run service account lacks the Cloud SQL Client role. — The Cloud Run service needs the Cloud SQL Client role (roles/cloudsql.client) on its service account to authorize connections to Cloud SQL. Without this IAM permission, the connection attempt is denied, resulting in the 'unable to connect' error shown in the log. This is the most common cause of connectivity failures between Cloud Run and Cloud SQL.
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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