This KCNA practice question tests your understanding of container orchestration. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A Kubernetes cluster has two nodes: control-plane and worker. The worker node runs several pods. The control-plane node becomes unreachable. What is the immediate impact on the pods running on the worker node?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Pods continue running, but new pods cannot be scheduled
When the control-plane node becomes unreachable, the kube-controller-manager cannot communicate with the kubelet on the worker node, so it stops performing scheduling and reconciliation. However, the kubelet on the worker node continues to run existing pods based on the last known desired state stored locally, and the pods themselves are managed by the container runtime (e.g., containerd) independently of the control-plane. Therefore, pods continue running normally, but no new pods can be scheduled because the scheduler, which runs on the control-plane, is unavailable.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
All pods are immediately terminated
Why it's wrong here
The kubelet continues running pods independently.
✓
Pods continue running, but new pods cannot be scheduled
Why this is correct
Existing pods keep running; scheduling requires the scheduler on the control plane.
Related concept
Read the scenario before looking for a memorised answer.
✗
Pods are rescheduled to the control-plane node
Why it's wrong here
The control-plane node is unreachable, so rescheduling is not possible.
✗
The worker node is automatically cordoned
Why it's wrong here
Cordoning requires interaction with the control plane.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume the control-plane is required for all pod operations, confusing the control-plane's role in scheduling and reconciliation with the kubelet's independent ability to maintain running workloads, leading them to choose immediate termination or automatic rescheduling.
Detailed technical explanation
How to think about this question
Under the hood, the kubelet on the worker node uses a local pod cache and continues to report status to the API server via heartbeats (node lease updates), but if the API server is unreachable, the kubelet cannot update pod status or receive new pod assignments. In a real-world scenario, if the control-plane is down for an extended period, the kubelet may eventually evict pods based on local resource pressure or if the pod's restart policy triggers, but it does not terminate them solely due to control-plane unavailability. The Kubernetes scheduler uses a scheduling queue and predicates (e.g., NodeResourcesFit, NodeName) to assign pods, and without the scheduler, no new pods can be placed on any node.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this KCNA question in full detail.
Container Orchestration — This question tests Container Orchestration — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Pods continue running, but new pods cannot be scheduled — When the control-plane node becomes unreachable, the kube-controller-manager cannot communicate with the kubelet on the worker node, so it stops performing scheduling and reconciliation. However, the kubelet on the worker node continues to run existing pods based on the last known desired state stored locally, and the pods themselves are managed by the container runtime (e.g., containerd) independently of the control-plane. Therefore, pods continue running normally, but no new pods can be scheduled because the scheduler, which runs on the control-plane, is unavailable.
What should I do if I get this KCNA question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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