Quick Answer
The answer is multi-stage builds, implemented by using multiple FROM statements in a single Dockerfile. This feature allows a DevOps engineer to reduce Docker image size by copying only the necessary runtime artifacts from intermediate build stages into the final image, leaving behind build-time dependencies, compilers, and temporary layers. On the CompTIA Linux+ XK0-005 exam, this concept tests your understanding of Dockerfile optimization and efficient containerization—a common trap is confusing multi-stage builds with simply chaining RUN commands or using smaller base images alone. The key distinction is that each FROM statement creates a new stage, and only the final stage becomes the image, so you can compile code in a heavy build stage and copy the binary to a lightweight runtime stage. A helpful memory tip: think of it as “build heavy, ship light”—use one stage to build, another to run, and the intermediate layers vanish.
This XK0-005 practice question tests your understanding of scripting, containers and automation. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 DevOps engineer wants to reduce the size of a Docker image by combining build stages. Which Dockerfile feature should be used?
RUN --mount=type=cache
Why wrong: Used for cache mounts, not multi-stage.
Layer caching
Why wrong: Helps build speed, not image size reduction.
Multi-stage builds (multiple FROM statements)
Copies only needed artifacts to final image.
Using a smaller base image like Alpine
Why wrong: Helps but not the feature for combining stages.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Multi-stage builds (multiple FROM statements)
Multi-stage builds, implemented by using multiple FROM statements in a single Dockerfile, allow a DevOps engineer to copy only the necessary artifacts from intermediate build stages into the final image. This eliminates build-time dependencies, tools, and intermediate layers from the final image, significantly reducing its size without sacrificing build functionality.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
RUN --mount=type=cache
Why it's wrong here
Used for cache mounts, not multi-stage.
Layer caching
Why it's wrong here
Helps build speed, not image size reduction.
Multi-stage builds (multiple FROM statements)
Why this is correct
Copies only needed artifacts to final image.
Related concept
Read the scenario before looking for a memorised answer.
Using a smaller base image like Alpine
Why it's wrong here
Helps but not the feature for combining stages.
Common exam traps
The trap here is that candidates confuse layer caching (a performance feature) with multi-stage builds (a size-reduction feature), or they assume using a smaller base image alone achieves the same result as eliminating entire build stages.
Detailed technical explanation
Under the hood, each FROM statement in a multi-stage build begins a new stage, and only the final stage (or a stage explicitly tagged) becomes the output image. The COPY --from=<stage_name> instruction copies files from a previous stage without carrying over its layers, meaning build tools like compilers or SDKs are excluded from the final image. In real-world CI/CD pipelines, this is critical for Go or Java applications where the build environment (e.g., golang:1.20 or maven:3.8) can be hundreds of megabytes, while the runtime image (e.g., alpine:3.18) is a fraction of that size.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Scripting, Containers and Automation — study guide chapter
Learn the concepts, then practise the questions
Scripting, Containers and Automation practice questions
Targeted practice on this topic area only
All XK0-005 questions
510 questions across all exam domains
CompTIA Linux+ XK0-005 study guide
Full concept coverage aligned to exam objectives
XK0-005 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise XK0-005 questions linked to Security.
Practise XK0-005 questions linked to Troubleshooting.
Practise XK0-005 questions linked to Scripting, Containers and Automation.
Practise XK0-005 questions linked to System Management.
Practise XK0-005 questions linked to XK0-005 fundamentals.
Practise XK0-005 questions linked to XK0-005 scenario.
Practise XK0-005 questions linked to XK0-005 troubleshooting.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Scripting, Containers and Automation — This question tests Scripting, Containers and Automation — Read the scenario before looking for a memorised answer..
The correct answer is: Multi-stage builds (multiple FROM statements) — Multi-stage builds, implemented by using multiple FROM statements in a single Dockerfile, allow a DevOps engineer to copy only the necessary artifacts from intermediate build stages into the final image. This eliminates build-time dependencies, tools, and intermediate layers from the final image, significantly reducing its size without sacrificing build functionality.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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 →
Last reviewed: Jun 25, 2026
This XK0-005 practice question is part of Courseiva's free CompTIA 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 XK0-005 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.