CKAD Practice Question: Application Environment, Configuration and Security
This CKAD practice question tests your understanding of application environment, configuration and security. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 pod is in 'CrashLoopBackOff' state. 'kubectl logs pod' shows: 'Error: listen tcp :8080: bind: permission denied'. The container runs as user '1000'. Which securityContext setting is missing?
Why wrong: Read-only root filesystem would cause write errors, not bind errors.
B
runAsUser: 0 (root)
Why wrong: Running as root is not recommended and may not solve the issue; the error is on port 8080, not a privileged port.
C
capabilities.add: ["NET_BIND_SERVICE"]
Although port 8080 is non-privileged, some container runtimes may require this capability for binding. It's a common fix for permission denied errors on ports.
D
seccompProfile: type: RuntimeDefault
Why wrong: Seccomp profiles restrict system calls; they could cause permission denied, but the error is about bind, which is a specific syscall. However, the typical fix is adding NET_BIND_SERVICE capability.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
capabilities.add: ["NET_BIND_SERVICE"]
The error 'listen tcp :8080: bind: permission denied' indicates the container process (running as user 1000) lacks the CAP_NET_BIND_SERVICE capability, which is required to bind to a privileged port (ports below 1024). Adding this capability via `capabilities.add: ["NET_BIND_SERVICE"]` grants the non-root user permission to bind to port 8080 without running as root.
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.
✗
readOnlyRootFilesystem: false
Why it's wrong here
Read-only root filesystem would cause write errors, not bind errors.
✗
runAsUser: 0 (root)
Why it's wrong here
Running as root is not recommended and may not solve the issue; the error is on port 8080, not a privileged port.
✓
capabilities.add: ["NET_BIND_SERVICE"]
Why this is correct
Although port 8080 is non-privileged, some container runtimes may require this capability for binding. It's a common fix for permission denied errors on ports.
Related concept
Read the scenario before looking for a memorised answer.
✗
seccompProfile: type: RuntimeDefault
Why it's wrong here
Seccomp profiles restrict system calls; they could cause permission denied, but the error is about bind, which is a specific syscall. However, the typical fix is adding NET_BIND_SERVICE capability.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume the only fix for a 'permission denied' bind error is to run as root (runAsUser: 0), but the CKAD exam expects you to know that specific Linux capabilities can be added to non-root users to solve such issues without compromising security.
Detailed technical explanation
How to think about this question
Under the hood, Linux capabilities are a subset of root privileges that can be granted to non-root processes; `CAP_NET_BIND_SERVICE` specifically allows binding to ports below 1024 (privileged ports). In Kubernetes, the `securityContext.capabilities.add` field directly modifies the container's capability set via the `capabilities` system call, and this is the standard way to allow a non-root user to bind to a low port without escalating to full root. A real-world scenario is running a web server as a non-root user on port 443 or 80, where adding this capability avoids the need to run the entire container as root.
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 CKAD question in full detail.
Application Environment, Configuration and Security — This question tests Application Environment, Configuration and Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: capabilities.add: ["NET_BIND_SERVICE"] — The error 'listen tcp :8080: bind: permission denied' indicates the container process (running as user 1000) lacks the CAP_NET_BIND_SERVICE capability, which is required to bind to a privileged port (ports below 1024). Adding this capability via `capabilities.add: ["NET_BIND_SERVICE"]` grants the non-root user permission to bind to port 8080 without running as root.
What should I do if I get this CKAD 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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This CKAD 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 CKAD exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.