KCNA Cloud Native Application Delivery Practice 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
```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?
⚠ Common exam trap
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).
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
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.
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.
- ✗
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.
Go deeper
Related to this question
About these practice questions
Courseiva writes every KCNA question from scratch — 833 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.