A team is debugging a Dockerfile that builds slowly. They notice that a `COPY` instruction for the application source is placed before a `RUN` instruction that installs dependencies. The team wants to improve build performance. Which change is most effective?

Use `ADD` instead of `COPY` for the source code

Move the `RUN` install command before the `FROM` instruction

Combine the `COPY` and `RUN` instructions into a single layer

Move the `COPY` instruction for the dependency manifest (e.g., `package.json`) before the `RUN` install command, and copy the rest of the source after

A team builds a single Dockerfile that is used to create images for both development and production environments. The development image needs debugging tools and a different entrypoint, while the production image should be minimal and not include those tools. The team wants to avoid maintaining two separate Dockerfiles. Which approach is most maintainable?

Use an `ARG` to conditionally include debugging tools in a single stage

Use `ENV` to set a variable that controls the entrypoint at runtime

Create two separate Dockerfiles: `Dockerfile.dev` and `Dockerfile.prod`

Use a multi-stage build with a `development` target and a `production` target, then build with `--target`

Which practice helps reduce the number of layers in an image?

Using multiple RUN instructions

A team is creating a Dockerfile for a small utility that runs a single binary. The binary is built on the host and placed in the build context. The team wants the image to be as small as possible and to include only the binary. Which Dockerfile is most appropriate?

`FROM scratch` then `COPY binary /binary` and `ENTRYPOINT ["/binary"]`

`FROM alpine` then `COPY binary /binary` and `ENTRYPOINT ["/binary"]`

`FROM ubuntu` then `COPY binary /binary` and `ENTRYPOINT ["/binary"]`

`FROM busybox` then `COPY binary /binary` and `ENTRYPOINT ["/binary"]`

LPI DevOps Tools Engineer

Domain 2Objective 3

702.3 Container Image Building (weight: 5) DEVOPS-TOOLS-ENGINEER Practice Questions (Page 4)

Part of the 702 Application Container domain, which makes up ~18% of our current practice bank. Linux Professional Institute does not publish an official question count, but from its 90-minute exam (~35–60 total, ~6–11 in this domain), expect 2–4 from this objective — we provide 28 practice questions to prepare you well beyond it. (estimate)

28questions here

6free pages

10concepts

Questions 16–20

16application · medium
A team is debugging a Dockerfile that builds slowly. They notice that a `COPY` instruction for the application source is placed before a `RUN` instruction that installs dependencies. The team wants to improve build performance. Which change is most effective?
Select an answer first
17foundation · easy
Which instruction in a Dockerfile is used to specify the user that runs the container process?
Select an answer first
18expert · hard
A team builds a single Dockerfile that is used to create images for both development and production environments. The development image needs debugging tools and a different entrypoint, while the production image should be minimal and not include those tools. The team wants to avoid maintaining two separate Dockerfiles. Which approach is most maintainable?
Select an answer first
19foundation · easy
Which practice helps reduce the number of layers in an image?
Select an answer first
20application · easy
A team is creating a Dockerfile for a small utility that runs a single binary. The binary is built on the host and placed in the build context. The team wants the image to be as small as possible and to include only the binary. Which Dockerfile is most appropriate?
Select an answer first

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702.3 Container Image Building (weight: 5) DEVOPS-TOOLS-ENGINEER Practice Questions (Page 4)

Questions 16–20

A team is debugging a Dockerfile that builds slowly. They notice that a `COPY` instruction for the application source is placed before a `RUN` instruction that installs dependencies. The team wants to improve build performance. Which change is most effective?

Which instruction in a Dockerfile is used to specify the user that runs the container process?

Which practice helps reduce the number of layers in an image?

A team is creating a Dockerfile for a small utility that runs a single binary. The binary is built on the host and placed in the build context. The team wants the image to be as small as possible and to include only the binary. Which Dockerfile is most appropriate?

Keep studying — 702 Application Container