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Deploying applications →mediumMultiple ChoiceObjective-mapped

PCD Deploying applications Practice Question

This PCD practice question tests your understanding of deploying applications. 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.

Exhibit

Refer to the exhibit.
```yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: frontend
spec:
  replicas: 3
  selector:
    matchLabels:
      app: frontend
  template:
    metadata:
      labels:
        app: frontend
    spec:
      containers:
      - name: frontend
        image: gcr.io/my-project/frontend:v2
        ports:
        - containerPort: 8080
        env:
        - name: BACKEND_URL
          value: "http://backend-service:8080"
      terminationGracePeriodSeconds: 30
```

After updating the image to v2, users report that the frontend application returns errors because it cannot reach the backend service. The backend service is running on GKE with the name 'backend-service' in the same namespace. 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.

Question 1mediummultiple choice
Full question →

Exhibit

Refer to the exhibit.
```yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: frontend
spec:
  replicas: 3
  selector:
    matchLabels:
      app: frontend
  template:
    metadata:
      labels:
        app: frontend
    spec:
      containers:
      - name: frontend
        image: gcr.io/my-project/frontend:v2
        ports:
        - containerPort: 8080
        env:
        - name: BACKEND_URL
          value: "http://backend-service:8080"
      terminationGracePeriodSeconds: 30
```

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 application expects the backend URL from an environment variable named BACKEND_SERVICE_URL, but the deployment sets BACKEND_URL.

The environment variable is set to BACKEND_URL, but the application likely expects a different variable name like BACKEND_SERVICE_URL. This mismatch causes the application to fail to find the backend URL.

Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.

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 selector labels do not match the pods.

    Why it's wrong here

    The exhibit shows the selector matches the pod labels, so this is not the issue.

  • ✓

    The application expects the backend URL from an environment variable named BACKEND_SERVICE_URL, but the deployment sets BACKEND_URL.

    Why this is correct

    Variable name mismatch is a common cause of application misconfiguration.

    Clue confirmation

    The clue word "most likely" in the question point toward this answer.

    Related concept

    Static NAT maps one inside address to one outside address.

  • ✗

    The backend service is not listening on port 8080.

    Why it's wrong here

    The port expected by the frontend matches the service port, so this is unlikely.

  • ✗

    The termination grace period is too short causing connection drops.

    Why it's wrong here

    Termination grace period affects shutdown, not connectivity issues.

Common exam traps

Common exam trap: NAT rules depend on direction and matching traffic

NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.

Trap categories for this question

  • Command / output trap

    The exhibit shows the selector matches the pod labels, so this is not the issue.

Detailed technical explanation

How to think about this question

NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.

KKey Concepts to Remember

  • Static NAT maps one inside address to one outside address.
  • PAT allows many inside hosts to share one public address using ports.
  • Inside local and inside global describe the private and translated addresses.
  • NAT ACLs identify traffic for translation, not always security filtering.

TExam Day Tips

  • Identify inside and outside interfaces first.
  • Check whether the scenario needs static NAT, dynamic NAT or PAT.
  • Do not confuse NAT matching ACLs with normal packet-filtering intent.

Key takeaway

NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.

Real-world example

How this comes up in practice

A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.

What to study next

Got this wrong? Here's your next step.

Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related PCD NAT questions on configuration and troubleshooting.

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FAQ

Questions learners often ask

What does this PCD question test?

Deploying applications — This question tests Deploying applications — Static NAT maps one inside address to one outside address..

What is the correct answer to this question?

The correct answer is: The application expects the backend URL from an environment variable named BACKEND_SERVICE_URL, but the deployment sets BACKEND_URL. — The environment variable is set to BACKEND_URL, but the application likely expects a different variable name like BACKEND_SERVICE_URL. This mismatch causes the application to fail to find the backend URL.

What should I do if I get this PCD question wrong?

Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related PCD NAT questions on configuration and troubleshooting.

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?

Static NAT maps one inside address to one outside address.

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Last reviewed: Jun 24, 2026

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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.