This KCNA practice question tests your understanding of kubernetes fundamentals. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 developer deploys a pod with the following resource specification:
```yaml
resources:
requests:
memory: "256Mi"
limits:
memory: "512Mi"
```
The pod is killed with OOMKilled. 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.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The container exceeded the memory limit of 512Mi
The OOMKilled exit code indicates the container was terminated by the Linux kernel's Out-Of-Memory (OOM) killer because it attempted to use more memory than its configured limit of 512Mi. Kubernetes enforces memory limits using cgroups; when the container exceeds the limit, the kernel kills the process, resulting in the OOMKilled status.
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 container exceeded the memory request of 256Mi
Why it's wrong here
Requests are used for scheduling; exceeding a request does not cause termination.
✗
The node ran out of memory
Why it's wrong here
The node may have memory pressure, but the direct cause is the container exceeding its limit.
✗
The CPU limit was too low
Why it's wrong here
CPU throttling does not cause OOMKilled; that is memory-related.
✓
The container exceeded the memory limit of 512Mi
Why this is correct
OOMKilled indicates the container exceeded its memory limit.
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.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CNCF often tests the distinction between requests and limits, trapping candidates who think exceeding a request causes termination, when in fact only exceeding the limit triggers OOMKilled.
Detailed technical explanation
How to think about this question
Under the hood, Kubernetes sets memory limits via cgroup memory.max (or memory.limit_in_bytes in older kernels). When the container's memory usage exceeds this value, the kernel triggers the OOM killer, which sends SIGKILL to the process. The pod's status. containerStatuses[].state.terminated.reason will be 'OOMKilled'. In real-world scenarios, memory limits should be set with headroom above expected usage to avoid unnecessary OOM kills, and monitoring tools like kubectl top pod or Prometheus can track actual memory consumption.
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 small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this KCNA question in full detail.
Kubernetes Fundamentals — This question tests Kubernetes Fundamentals — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The container exceeded the memory limit of 512Mi — The OOMKilled exit code indicates the container was terminated by the Linux kernel's Out-Of-Memory (OOM) killer because it attempted to use more memory than its configured limit of 512Mi. Kubernetes enforces memory limits using cgroups; when the container exceeds the limit, the kernel kills the process, resulting in the OOMKilled status.
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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Question Discussion
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