200-901 Application Deployment and Security Practice Question
A team deploys a containerized web application and wants to verify that the image running in production was built from the reviewed source and has not been altered since. Which practice directly provides this guarantee?
⚠ Common exam trap
The trap here is treating the latest tag or a shared repository as proof of provenance, when only an immutable digest plus signature verification actually binds the running image to reviewed code.
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
✓
Reference the image by an immutable digest and enable Docker Content Trust so only signed images are pulled.
Verifying that a running container corresponds to reviewed, unmodified source requires two properties: immutability and authenticity. Pinning by digest makes the image reference immutable, and content trust verifies the signature of the publisher. Mutable tags and build-hygiene practices cannot demonstrate either property, so only the combination of digest pinning and signing answers the question.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Store the Dockerfile in the same repository as the application source code.
Why it's wrong here
Keeping the Dockerfile with the source is good hygiene and aids reproducibility, but it does not prove that the image in production was built from that Dockerfile. Nothing prevents a different image from being pushed or pulled under the same tag. The practice is useful but does not deliver the verification the team needs.
- ✗
Tag the image with the string latest so every deployment uses the newest build.
Why it's wrong here
The latest tag is a mutable pointer that can be reassigned to any image at any time, so it provides no evidence about which source produced the running container. Two hosts pulling latest on different days can run entirely different code under the same tag. It offers no integrity or provenance guarantee whatsoever.
- ✗
Run docker image prune on the production host before each deployment.
Why it's wrong here
Pruning removes unused images to reclaim disk space. It has no relationship to verifying provenance or integrity and could even delete a cached image the team intended to reuse. It does not authenticate the image, pin its contents, or detect tampering in any way.
- ✓
Reference the image by an immutable digest and enable Docker Content Trust so only signed images are pulled.
Why this is correct
A digest is a cryptographic hash of the image manifest, so referencing it pins the exact bits that were reviewed. Docker Content Trust uses signing keys to verify that the publisher authorized the image before it is pulled. Together they prove the running container matches the approved artifact and that it was not tampered with in transit or in the registry.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
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.