KCNA Container Orchestration Practice Question
A pod is running but its container exits with code 137. The pod logs show 'Killed'. What is the most likely cause?
⚠ Common exam trap
CNCF often tests the distinction between CPU throttling (which does not kill) and OOMKill (which does), and the trap here is that candidates confuse 'Killed' in logs with a generic failure, not recognizing exit code 137 as the specific OOMKill signal.
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 container was OOMKilled due to memory limit
Exit code 137 (128 + 9) indicates the container was terminated by SIGKILL. Combined with 'Killed' in logs, this is the definitive signature of an OOMKill event, where the Linux kernel's Out-Of-Memory (OOM) killer terminates the container process because it exceeded its memory limit (specified in the pod's resource limits). Kubernetes enforces memory limits via cgroups, and when the container's memory usage surpasses the limit, the OOM killer sends SIGKILL, resulting in exit code 137.
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's CPU limit was exceeded
Why it's wrong here
CPU limits throttle, they do not kill the container.
- ✗
The container's liveness probe failed
Why it's wrong here
A failed liveness probe would cause a restart, but exit code would be 1 or similar, not 137.
- ✓
The container was OOMKilled due to memory limit
Why this is correct
Exit code 137 is SIGKILL, often from OOM. The pod status would show OOMKilled.
- ✗
The node ran out of disk space
Why it's wrong here
Disk pressure may evict pods, but exit code would be different.
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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.