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Cloud Native Application Delivery →easyMultiple ChoiceObjective-mapped

KCNA Cloud Native Application Delivery Practice Question

This KCNA practice question tests your understanding of cloud native application delivery. 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.

```
apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web
  template:
    metadata:
      labels:
        app: web
    spec:
      containers:
      - name: app
        image: nginx:1.21
        ports:
        - containerPort: 80
        readinessProbe:
          httpGet:
            path: /health
            port: 80
          initialDelaySeconds: 5
          periodSeconds: 10
```

Refer to the exhibit. The deployment above is created, but the pods are not receiving traffic from the associated Service. The Service selector matches 'app: web'. The Service endpoints list is empty. 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 1easymultiple choice
Full question →

Exhibit

Refer to the exhibit.

```
apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web
  template:
    metadata:
      labels:
        app: web
    spec:
      containers:
      - name: app
        image: nginx:1.21
        ports:
        - containerPort: 80
        readinessProbe:
          httpGet:
            path: /health
            port: 80
          initialDelaySeconds: 5
          periodSeconds: 10
```

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 readiness probe endpoint /health does not exist in the nginx container

The correct answer is C because a readiness probe that fails (e.g., the /health endpoint does not exist in the nginx container) will cause the pod to be marked as not ready. Kubernetes removes pods with failing readiness probes from the Service's endpoints list, resulting in an empty endpoints list even though the Service selector matches the pod labels. This is a common misconfiguration where the probe endpoint is not actually served by the container.

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 Service selector does not match the pod labels

    Why it's wrong here

    The Service selector 'app: web' matches the pod labels 'app: web' from the deployment template.

  • ✗

    The containerPort is set to 80, but the Service targetPort is 8080

    Why it's wrong here

    There is no information about the Service in the exhibit; assuming targetPort matches containerPort is standard; if it didn't, endpoints might still exist but not work.

  • ✓

    The readiness probe endpoint /health does not exist in the nginx container

    Why this is correct

    The readiness probe is configured to GET /health on port 80, but the default nginx image does not serve a /health page. The probe fails, so the pod is not ready and is removed from Service endpoints.

    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 nginx:1.21 image is not available in the container registry

    Why it's wrong here

    The image nginx:1.21 is a valid public image; if it were unavailable, the pod would have ImagePullBackOff, not a missing endpoint.

Common exam traps

Common exam trap: answer the scenario, not the keyword

CNCF often tests the distinction between readiness probes and liveness probes, and the trap here is that candidates assume a missing endpoint only affects liveness (causing restarts) rather than readiness (causing removal from Service endpoints).

Detailed technical explanation

How to think about this question

Readiness probes are used by kubelet to determine when a container is ready to accept traffic. If the probe fails, the pod's Ready condition is set to False, and the endpoint controller removes the pod's IP from the Service's Endpoints object. This is distinct from liveness probes, which restart the container. In real-world scenarios, a common mistake is defining a readiness probe for an endpoint that the application does not expose (e.g., /health on nginx without a custom config), causing the pod to never become ready and thus never receive traffic from the Service.

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 practitioner preparing for the KCNA exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.

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.

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FAQ

Questions learners often ask

What does this KCNA question test?

Cloud Native Application Delivery — This question tests Cloud Native Application Delivery — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: The readiness probe endpoint /health does not exist in the nginx container — The correct answer is C because a readiness probe that fails (e.g., the /health endpoint does not exist in the nginx container) will cause the pod to be marked as not ready. Kubernetes removes pods with failing readiness probes from the Service's endpoints list, resulting in an empty endpoints list even though the Service selector matches the pod labels. This is a common misconfiguration where the probe endpoint is not actually served by the container.

What should I do if I get this KCNA 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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Last reviewed: Jun 30, 2026

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This KCNA practice question is part of Courseiva's free CNCF 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 KCNA exam.