KCNA Kubernetes Fundamentals Practice Question
A pod has resource requests: cpu: 250m, memory: 512Mi and limits: cpu: 500m, memory: 1Gi. If the container tries to use 600m CPU and 700Mi memory, what will happen?
⚠ Common exam trap
Candidates often confuse compressible (CPU) and non-compressible (memory) resources, incorrectly assuming that exceeding any limit leads to termination, whereas CPU only causes throttling and memory causes termination.
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 will be throttled for CPU, but will not be killed because memory is within limits
CPU is a compressible resource: exceeding the CPU limit (500m) causes throttling, not termination. Memory is a non-compressible resource, and since the container's memory usage (700Mi) is below its limit (1Gi), it will not be killed. The container will be CPU-throttled but allowed to continue running.
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 will be allowed to use the extra resources because limits are only soft constraints
Why it's wrong here
Limits are hard ceilings enforced by the kubelet, not soft constraints, so 600m CPU is capped at 500m and 700Mi memory stays under the 1Gi limit. It is tempting because requests behave as scheduling hints, but limits are enforced, not advisory.
- ✗
The container will be throttled for CPU and may be terminated if it continues to exceed the limit
Why it's wrong here
CPU is compressible, so exceeding 500m causes throttling, but memory at 700Mi is below the 1Gi limit, so no termination occurs. It is tempting because throttling is genuinely the CPU behaviour, yet the termination clause misstates the memory position.
- ✓
The container will be throttled for CPU, but will not be killed because memory is within limits
Why this is correct
CPU is a compressible resource, so exceeding the 500m limit triggers CFS throttling rather than termination. Memory is incompressible, but 700Mi stays below the 1Gi limit, so no OOM kill occurs. The constraint satisfied is that only memory overage causes container termination.
- ✗
The container will be killed immediately because it exceeded its CPU limit
Why it's wrong here
CPU overuse triggers throttling via cgroup quota, not immediate killing; only memory limit breaches cause OOM termination. It is tempting because exceeding limits has consequences, but the CPU mechanism is throttling, and 700Mi sits below the 1Gi memory limit anyway.
Go deeper
Related to this question
About these practice questions
Courseiva writes every KCNA question from scratch — 930 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.