KCNA Kubernetes Fundamentals Practice Question
You run 'kubectl get pods' and see a pod in 'Pending' state for over 5 minutes. You describe the pod and see '0/1 nodes are available: 1 Insufficient memory'. What is the most likely cause?
⚠ Common exam trap
CNCF often tests the distinction between resource requests (used for scheduling) and resource limits (used for throttling/eviction), so candidates mistakenly think a large image or probe failure causes Pending state, but the scheduler only cares about resource requests and node availability.
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 pod's memory request is larger than any node's allocatable memory
The '0/1 nodes are available: 1 Insufficient memory' message indicates that the Kubernetes scheduler could not place the pod because no node has enough allocatable memory to satisfy the pod's memory request. Option B is correct because the pod's memory request exceeds the available memory on any node, causing the pod to remain in Pending state indefinitely until sufficient resources become available.
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 image is too large
Why it's wrong here
Image size affects pull duration, not scheduling; the scheduler reports Insufficient memory because no node has enough allocatable RAM for the pod's requests. Large images matter when pods stay in ContainerCreating or ImagePullBackOff, not Pending with a memory message.
- ✓
The pod's memory request is larger than any node's allocatable memory
Why this is correct
The scheduler's event shows insufficient memory on all nodes, meaning the pod's memory request exceeds every node's allocatable capacity. That unmet resource request is precisely why the scheduler cannot bind the pod, leaving it Pending.
- ✗
The pod has a liveness probe that is failing
Why it's wrong here
A failing liveness probe restarts an already-running container, producing CrashLoopBackOff or restarts, not Pending. The scheduler never placed the pod because no node had sufficient allocatable memory; probes only execute after scheduling and container start.
- ✗
The kubelet on the node is not running
Why it's wrong here
A stopped kubelet makes the node NotReady, so pods are not scheduled there at all; the message here names memory as the binding constraint. Kubelet failure is the diagnosis when nodes report NotReady or pods vanish from a healthy node.
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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.