EX188 Container Image Building Practice Question
Which THREE conditions or practices can cause layer cache invalidation during a 'podman build' operation? (Choose three.)
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
✓
Modifying the content or modification timestamp (mtime) of a file referenced by a COPY instruction.
Cache invalidation happens when instructions change, files change (checksum/mtime), or ARG values change.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Adding a comment line '#' at the very top of the Containerfile before the first FROM instruction.
Why it's wrong here
Comments generally do not invalidate subsequent layer cache unless parsed as special directives like syntax parsers.
- ✓
Modifying the content or modification timestamp (mtime) of a file referenced by a COPY instruction.
Why this is correct
File changes invalidate the cache for that instruction and all following ones.
- ✓
Changing the order of instructions within the Containerfile.
Why this is correct
Instruction order changes invalidate cache for altered steps.
- ✓
Passing a different value to an 'ARG' instruction via '--build-arg' compared to the previous build.
Why this is correct
Changing build arguments invalidates the cache for that ARG and subsequent instructions using it.
- ✗
Running 'podman build' on a different physical workstation while using the exact same build context and Containerfile.
Why it's wrong here
Content-addressable caching works independently of the host workstation as long as inputs are identical.
About these practice questions
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official Red Hat exam blueprint
This EX188 practice question is part of Courseiva's free Red Hat 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 EX188 exam.