This CKS practice question tests your understanding of cluster setup and hardening. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
An administrator wants to restrict which nodes a pod can be scheduled on using the NodeRestriction admission plugin. Which flag must be set on the kube-apiserver to enable this plugin?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
--enable-admission-plugins=NodeRestriction
The NodeRestriction admission plugin limits the labels and taints that a kubelet running on a node can modify on its own Node object. To enable it, the `--enable-admission-plugins=NodeRestriction` flag must be set on the kube-apiserver, as admission plugins are enabled via this flag. This plugin works in conjunction with the Node authorizer and the NodeRestriction admission controller to enforce node-level restrictions.
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.
✗
--admission-control=NodeRestriction
Why it's wrong here
The --admission-control flag is deprecated; use --enable-admission-plugins.
✗
--enable-admission-plugins=PodNodeSelector
Why it's wrong here
PodNodeSelector is not a standard admission plugin; the correct plugin is NodeRestriction.
✗
--authorization-mode=Node
Why it's wrong here
Node authorization mode is for kubelet authorization, not for restricting pod scheduling.
✓
--enable-admission-plugins=NodeRestriction
Why this is correct
This flag enables the NodeRestriction admission plugin, which enforces node restrictions on pods.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse the deprecated `--admission-control` flag with the current `--enable-admission-plugins` flag, or they mix up the NodeRestriction plugin with the Node authorizer or the PodNodeSelector plugin.
Detailed technical explanation
How to think about this question
The NodeRestriction admission plugin intercepts requests to create or update Node objects and ensures that a kubelet can only modify labels with the `node-restriction.kubernetes.io/` prefix and taints within its own node. It is a critical security control to prevent a compromised kubelet from impersonating other nodes or escalating privileges. In practice, it is often used alongside the Node authorizer and the `--kubelet-certificate-authority` flag to enforce a defense-in-depth approach for node identity.
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 junior network technician can log in to a core router but cannot reach the enable prompt or configuration mode. The AAA server is authenticating the login — but the authorisation policy only grants privilege level 1, not 15. Authentication (who you are) is working; authorisation (what you can do) is not.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CKS question in full detail.
Cluster Setup and Hardening — This question tests Cluster Setup and Hardening — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: --enable-admission-plugins=NodeRestriction — The NodeRestriction admission plugin limits the labels and taints that a kubelet running on a node can modify on its own Node object. To enable it, the `--enable-admission-plugins=NodeRestriction` flag must be set on the kube-apiserver, as admission plugins are enabled via this flag. This plugin works in conjunction with the Node authorizer and the NodeRestriction admission controller to enforce node-level restrictions.
What should I do if I get this CKS 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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