← PCD·Google Cloud

Question 40 of 500

Deploying applications →hardMultiple ChoiceObjective-mapped

PCD Deploying applications Practice Question

This PCD practice question tests your understanding of deploying applications. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. 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 runs a Java microservice on Google Kubernetes Engine (GKE) using a standard cluster with 3 nodes. They use Cloud Build to build the Docker image and push it to Artifact Registry, then apply a Kubernetes Deployment manifest that references the new image tag. The Deployment has a rolling update strategy with maxSurge=1 and maxUnavailable=0. After a recent deployment, the new pods crash with 'CrashLoopBackOff'. The old pods are still running successfully. The application logs show a connection refused error when trying to connect to a Cloud SQL instance. The Cloud SQL instance is in the same project and region. The GKE cluster nodes have the appropriate scopes to access Cloud SQL. The application uses a Cloud SQL proxy sidecar container to establish the connection. The previous deployment worked fine. What is the most likely cause of the failure?

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.

Question 1hardmultiple choice

Full question →

A
The GKE cluster nodes do not have the Cloud SQL Client role.
Why wrong: Incorrect. The nodes have appropriate scopes (stated), and such a role issue would affect all pods, not just new ones.
B
The Cloud SQL proxy sidecar container is not included in the new Deployment revision.
Correct. Without the sidecar, the application cannot connect to Cloud SQL, resulting in connection refused.
C
The Kubernetes Secret containing the service account key was not updated to include the new pod's service account.
Why wrong: Incorrect. Secrets are static and do not need updating per pod; the issue is about the sidecar container.
D
The new image tag points to a broken build that has incorrect code for Cloud SQL connection.
Why wrong: Incorrect. A code issue would cause a different error (e.g., authentication failure), not connection refused to the proxy.

Full breakdown with real-world context →

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 Cloud SQL proxy sidecar container is not included in the new Deployment revision.

The correct answer is B because the Cloud SQL proxy sidecar container is missing from the new Deployment revision. Since the application relies on the sidecar to establish a secure connection to Cloud SQL, its absence causes the connection refused error. The old pods continue to run because they still have the sidecar from the previous Deployment revision, while the new pods crash due to the missing proxy.

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 GKE cluster nodes do not have the Cloud SQL Client role.
Why it's wrong here
Incorrect. The nodes have appropriate scopes (stated), and such a role issue would affect all pods, not just new ones.
✓
The Cloud SQL proxy sidecar container is not included in the new Deployment revision.
Why this is correct
Correct. Without the sidecar, the application cannot connect to Cloud SQL, resulting in connection refused.
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 Kubernetes Secret containing the service account key was not updated to include the new pod's service account.
Why it's wrong here
Incorrect. Secrets are static and do not need updating per pod; the issue is about the sidecar container.
✗
The new image tag points to a broken build that has incorrect code for Cloud SQL connection.
Why it's wrong here
Incorrect. A code issue would cause a different error (e.g., authentication failure), not connection refused to the proxy.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Cisco often tests the misconception that a connection refused error implies a code or permission issue, when in fact it is a missing sidecar container that causes the failure, especially in scenarios where the sidecar is defined in the Deployment manifest and accidentally removed during a revision update.

Detailed technical explanation

How to think about this question

The Cloud SQL proxy sidecar container runs as a separate container in the same pod, listening on localhost (127.0.0.1:5432 for PostgreSQL or 3306 for MySQL) and forwarding traffic to the Cloud SQL instance via an encrypted tunnel using the Cloud SQL Auth Proxy. When the sidecar is omitted, the application's connection string (e.g., jdbc:postgresql://localhost:5432/db) fails because no process is listening on that port, resulting in a connection refused error. In a rolling update with maxSurge=1 and maxUnavailable=0, the new pods must become healthy before the old ones are terminated, so the old pods continue to serve traffic while the new ones crash.

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.

Related PCD practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

Designing highly scalable, available, and reliable cloud-native applications practice questions

Practise PCD questions linked to Designing highly scalable, available, and reliable cloud-native applications.

Building and testing applications practice questions

Practise PCD questions linked to Building and testing applications.

Deploying applications practice questions

Practise PCD questions linked to Deploying applications.

Integrating Google Cloud services practice questions

Practise PCD questions linked to Integrating Google Cloud services.

Managing application performance monitoring practice questions

Practise PCD questions linked to Managing application performance monitoring.

PCD fundamentals practice questions

Practise PCD questions linked to PCD fundamentals.

PCD scenario practice questions

Practise PCD questions linked to PCD scenario.

PCD troubleshooting practice questions

Practise PCD questions linked to PCD troubleshooting.

Practice this exam

Start a free PCD practice session

Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.

10 questions 20 questions 30 questions 50 questions Timed 30

PCD practice-test guide →Study guide →Browse all practice tests

FAQ

Questions learners often ask

What does this PCD question test?

Deploying applications — This question tests Deploying applications — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: The Cloud SQL proxy sidecar container is not included in the new Deployment revision. — The correct answer is B because the Cloud SQL proxy sidecar container is missing from the new Deployment revision. Since the application relies on the sidecar to establish a secure connection to Cloud SQL, its absence causes the connection refused error. The old pods continue to run because they still have the sidecar from the previous Deployment revision, while the new pods crash due to the missing proxy.

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.

About these practice questions

Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →

How Courseiva writes practice questions · Editorial policy

Keep practising

Question Discussion

Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.

Loading comments…

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.