This CKS practice question tests your understanding of cluster setup. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 security audit reveals that the kube-apiserver is using the default insecure port 8080 on a production cluster. Which is the most secure and recommended remediation?
Why wrong: Setting to 0 disables the insecure port; however the question asks for the most secure remediation. This is correct but the option is misleading as it only changes port number.
B
Set --insecure-port=0 and ensure --secure-port=6443 is configured
Setting insecure-port to 0 disables it, and secure-port=6443 uses TLS.
C
Set --insecure-port=6443
Why wrong: This would run the insecure API on 6443, which is not recommended.
D
Set --secure-port=8080
Why wrong: This sets the secure port to 8080, but the insecure port may still be enabled.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Set --insecure-port=0 and ensure --secure-port=6443 is configured
Setting `--insecure-port=0` disables the unencrypted HTTP port (default 8080), which eliminates the risk of unauthenticated access to the API server. Ensuring `--secure-port=6443` is configured enforces TLS-encrypted communication on the standard secure port, which is the only recommended and secure method for production clusters.
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.
✗
Change the --insecure-port flag to 0
Why it's wrong here
Setting to 0 disables the insecure port; however the question asks for the most secure remediation. This is correct but the option is misleading as it only changes port number.
✓
Set --insecure-port=0 and ensure --secure-port=6443 is configured
Why this is correct
Setting insecure-port to 0 disables it, and secure-port=6443 uses TLS.
Related concept
Read the scenario before looking for a memorised answer.
✗
Set --insecure-port=6443
Why it's wrong here
This would run the insecure API on 6443, which is not recommended.
✗
Set --secure-port=8080
Why it's wrong here
This sets the secure port to 8080, but the insecure port may still be enabled.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CNCF often tests the misconception that simply changing the insecure port number or setting it to a non-default value is sufficient, whereas the only secure remediation is to disable it entirely with `--insecure-port=0` and explicitly enable the secure port.
Detailed technical explanation
How to think about this question
The kube-apiserver's `--insecure-port` flag (default 8080) binds to an HTTP listener that bypasses authentication and authorization, making it a severe security risk. The `--secure-port` flag (default 6443) uses TLS and requires valid client certificates or tokens. In production, the insecure port must be disabled entirely by setting `--insecure-port=0`, and the secure port must be explicitly configured to ensure the API server only listens on a TLS-protected endpoint. This aligns with CIS Kubernetes Benchmark recommendations and the principle of defense in depth.
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 CKS question in full detail.
Cluster Setup — This question tests Cluster Setup — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Set --insecure-port=0 and ensure --secure-port=6443 is configured — Setting `--insecure-port=0` disables the unencrypted HTTP port (default 8080), which eliminates the risk of unauthenticated access to the API server. Ensuring `--secure-port=6443` is configured enforces TLS-encrypted communication on the standard secure port, which is the only recommended and secure method for production clusters.
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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