This KCNA practice question tests your understanding of container orchestration. 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.
```
$ kubectl describe pod web-pod
...
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 10m default-scheduler Successfully assigned default/web-pod to node-1
Normal Pulling 10m kubelet Pulling image "nginx:latest"
Warning Failed 9m58s kubelet Failed to pull image "nginx:latest": rpc error: code = NotFound desc = image not found
Warning BackOff 9m57s kubelet Back-off pulling image
```
Based on the exhibit, why is the pod web-pod not running?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The container image is not available in the registry.
Option B is correct because the pod's status indicates an ImagePullBackOff error, which occurs when the kubelet fails to pull the specified container image from the registry. This typically means the image name or tag is incorrect, the registry is unreachable, or the image does not exist in the registry. The exhibit shows the pod is stuck in a waiting state with the reason 'ErrImagePull' or 'ImagePullBackOff', directly pointing to a missing or inaccessible image.
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.
✗
A network policy is blocking the image pull.
Why it's wrong here
The error is 'image not found', not a network timeout or denial.
✓
The container image is not available in the registry.
Why this is correct
The error 'image not found' confirms the image is missing.
Related concept
Read the scenario before looking for a memorised answer.
✗
The node does not have enough memory.
Why it's wrong here
No resource shortage events are shown.
✗
The pod was not scheduled onto a node.
Why it's wrong here
The event 'Successfully assigned' indicates scheduling succeeded.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distinction between pod scheduling failures (e.g., resource constraints, taints/tolerations) and container runtime failures (e.g., image pull errors), so candidates may confuse a 'Pending' pod with an 'ImagePullBackOff' pod, both of which are not running but have different root causes.
Trap categories for this question
Command / output trap
No resource shortage events are shown.
Detailed technical explanation
How to think about this question
Under the hood, when a pod is scheduled, the kubelet on the assigned node instructs the container runtime to pull the image using the configured image pull policy (e.g., Always, IfNotPresent). The runtime contacts the registry (e.g., Docker Hub, private registry) over HTTPS, and if the image manifest is not found (HTTP 404) or authentication fails, the runtime returns an error that the kubelet surfaces as ImagePullBackOff, with an exponential backoff delay (starting at 300ms, doubling up to 5 minutes). In real-world scenarios, this often happens due to typos in the image tag, missing tags (e.g., using 'latest' when no tag exists), or expired registry credentials.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this KCNA question in full detail.
Container Orchestration — This question tests Container Orchestration — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The container image is not available in the registry. — Option B is correct because the pod's status indicates an ImagePullBackOff error, which occurs when the kubelet fails to pull the specified container image from the registry. This typically means the image name or tag is incorrect, the registry is unreachable, or the image does not exist in the registry. The exhibit shows the pod is stuck in a waiting state with the reason 'ErrImagePull' or 'ImagePullBackOff', directly pointing to a missing or inaccessible image.
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.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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