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200-901 Practice Question: Which TWO are valid methods to secure a Docker…
Which TWO are valid methods to secure a Docker container?
⚠ Common exam trap
Cisco often tests the misconception that 'running as root inside a container is safe because the container is isolated,' but the trap here is that root inside a container is the same UID 0 on the host if the container is not run with a user namespace remapping or `--user` flag, making it a direct privilege escalation vector.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use read-only filesystem
Mounting the container's filesystem as read-only prevents any process inside the container from writing to the filesystem, which blocks malware persistence, log tampering, and unauthorized configuration changes. This is enforced by the Linux kernel's mount namespace and can be set with the `--read-only` flag in `docker run`. It is a key principle of immutable infrastructure for containers.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Use read-only filesystem
Why this is correct
Read-only filesystem prevents container from modifying files.
- ✗
Expose all ports
Why it's wrong here
Exposing all ports increases attack surface.
- ✓
Set resource limits
Why this is correct
Resource limits prevent container from consuming excessive resources.
- ✗
Run containers as root
Why it's wrong here
Running as root increases security risk.
- ✗
Disable network isolation
Why it's wrong here
Disabling network isolation reduces security.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-901 practice question is part of Courseiva's free Cisco 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 200-901 exam.