KCNA Kubernetes Fundamentals Practice Question
A pod remains in 'Pending' state. Upon inspecting the pod with 'kubectl describe pod', you see the message '0/1 nodes are available: 1 node(s) had taint {node.kubernetes.io/disk-pressure: }, that the pod didn't tolerate'. What is the most likely cause?
⚠ Common exam trap
In the KCNA exam, it's important to distinguish between taint/toleration errors and resource insufficiency errors. Candidates often mistakenly choose 'resource requests exceed capacity' when the message explicitly mentions a taint, not resource limits.
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 node has a disk pressure condition and the pod lacks a toleration
The message '0/1 nodes are available: 1 node(s) had taint {node.kubernetes.io/disk-pressure: }, that the pod didn't tolerate' indicates the node has a taint of 'disk-pressure' which prevents pod scheduling unless the pod has a matching toleration. Since the pod lacks this toleration, it remains in 'Pending' state. Option B correctly identifies the node's disk pressure condition and the missing toleration as the cause.
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 is not using a ServiceAccount
Why it's wrong here
ServiceAccount absence does not block scheduling; pods run with the namespace default account, and admission would reject the pod outright. It is tempting because RBAC and identity misconfiguration cause many failures, and would be correct if the pod were Running but unable to reach the API server.
- ✓
The node has a disk pressure condition and the pod lacks a toleration
Why this is correct
The scheduler's message names the taint node.kubernetes.io/disk-pressure, meaning the node reports disk pressure. Because the pod defines no matching toleration, the scheduler refuses to bind it, leaving it Pending. This matches the stem's constraint exactly.
- ✗
The pod's resource requests exceed the node's capacity
Why it's wrong here
Exceeding node capacity produces 'Insufficient cpu/memory' events, not a disk-pressure taint rejection. Resource requests are tempting because they are the most common scheduling failure, and would be the answer if the message cited insufficient allocatable resources rather than an untolerated taint.
- ✗
The pod's container image does not exist
Why it's wrong here
A missing image surfaces as ImagePullBackOff or ErrImagePull after scheduling succeeds, never as a Pending pod with a taint message. It is tempting because image faults are frequent, and would be correct if the pod had already been assigned to a node and the kubelet reported pull failures.
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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.