The answer is setting `securityContext.readOnlyRootFilesystem: true` and `securityContext.capabilities.drop: ["ALL"]`. These two actions enforce a defense-in-depth approach to container security to prevent compromise: making the root filesystem read-only blocks an attacker from modifying binaries or configuration files, while dropping all Linux capabilities strips the container of privileged system calls that could be used for escalation. On the CKAD exam, this tests your understanding of Pod security contexts as a core hardening technique, often appearing in multi-select questions where you must distinguish between runtime restrictions and network policies. A common trap is confusing `readOnlyRootFilesystem` with volume mounts—remember that temporary directories like `/tmp` can still be written to unless explicitly mounted. For a quick memory tip, think “Read-Only Roots and No Caps” to recall that locking down filesystem write access and removing all capabilities together create a minimal attack surface, making it far harder for an intruder to pivot or persist.
CKAD Practice Question: Application Environment, Configuration and Security
This CKAD practice question tests your understanding of application environment, configuration and security. 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.
Which TWO actions can help prevent a container from being compromised if an attacker gains access? (Select 2)
Setting `securityContext.readOnlyRootFilesystem: true` makes the container's root filesystem read-only, preventing an attacker who gains access from modifying system binaries, libraries, or configuration files. This is a key defense-in-depth measure that limits the impact of a compromise by restricting write access to only explicitly mounted volumes.
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.
Common exam trap: answer the scenario, not the keyword
CNCF often tests the misconception that running as a non-root user (e.g., `runAsUser: 1000`) is sufficient, but the trap here is that `runAsUser: 0` explicitly sets root, which is a common mistake when candidates confuse 'default' with 'secure'—always drop all capabilities and make the filesystem read-only for defense in depth.
Detailed technical explanation
How to think about this question
Under the hood, `readOnlyRootFilesystem` leverages Linux kernel mount flags (MS_RDONLY) to enforce a read-only overlay filesystem for the container's rootfs, while `capabilities.drop: ["ALL"]` removes all Linux capabilities (e.g., CAP_NET_RAW, CAP_SYS_ADMIN) from the container's bounding set, effectively running it as a non-privileged process. In a real-world scenario, even if an attacker exploits an application vulnerability, they cannot install malware, modify cron jobs, or use raw sockets without these capabilities.
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: Setting securityContext.readOnlyRootFilesystem: true — Setting `securityContext.readOnlyRootFilesystem: true` makes the container's root filesystem read-only, preventing an attacker who gains access from modifying system binaries, libraries, or configuration files. This is a key defense-in-depth measure that limits the impact of a compromise by restricting write access to only explicitly mounted volumes.
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.
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Question Discussion
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