KCNA Container Orchestration Practice Question
A pod is stuck in the 'Pending' state. You run 'kubectl describe pod mypod' and see the event: '0/3 nodes are available: 1 node had taint that the pod didn't tolerate, 2 Insufficient cpu.' What is the most likely cause?
⚠ Common exam trap
It's easy for candidates to confuse 'Pending' state with post-scheduling issues like probe failures or image pull errors, but the event message explicitly points to scheduling failures (resource insufficiency and taint intolerance), which are the only reasons a pod remains unscheduled.
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 resource requests exceed available node capacity and a node taint is not tolerated
The pod is in 'Pending' state because the scheduler cannot find a node that meets its requirements. The event '0/3 nodes are available: 1 node had taint that the pod didn't tolerate, 2 Insufficient cpu' directly indicates that the pod's resource requests exceed the available CPU on two nodes, and the remaining node has a taint that the pod does not tolerate. This matches option B: the pod's resource requests exceed available node capacity and a node taint is not tolerated.
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 pod's liveness probe is failing
Why it's wrong here
A failing liveness probe causes container restarts and a Running pod, not Pending; the scheduler's event cites taints and insufficient CPU, so no node was ever selected. Liveness probes are tempting because they are a common pod fault, but they act after scheduling, on an already-running container.
- ✓
The pod's resource requests exceed available node capacity and a node taint is not tolerated
Why this is correct
The scheduler events show two independent blockers: insufficient CPU on two nodes and an untolerated taint on the third. The pod's resource requests exceed schedulable capacity, and no node both satisfies those requests and tolerates the taint.
- ✗
The pod's container runtime is not installed
Why it's wrong here
A missing container runtime would leave nodes NotReady, so the scheduler would report no available nodes rather than citing taints and insufficient CPU on three Ready nodes. Container runtimes are tempting because they underpin pod execution, but the event's specific reasons point to scheduling predicates, not node health.
- ✗
The pod's image pull secret is missing
Why it's wrong here
A missing image pull secret produces ImagePullBackOff or ErrImagePull once a node has been selected and kubelet attempts the pull; the Pending event here shows the scheduler rejected every node for taints and CPU. Image pull secrets are tempting because they block container startup, but they never affect scheduling.
About these practice questions
This KCNA question is part of Courseiva's 930-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam 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.