A developer is building a Docker image for a web application. The build context contains a large node_modules directory and a .env file with production secrets. The developer wants to copy only the application source code into the image and avoid sending unnecessary files to the Docker daemon. Which approach is correct?

Use RUN cp -r . /app after setting WORKDIR

Use COPY node_modules /app and COPY .env /app

Use COPY . /app and add a .dockerignore file that excludes node_modules and .env

Use ADD . /app and rely on ADD's automatic exclusion of node_modules

A team is building a Docker image for a production application. They want to ensure that the image is reproducible and that builds do not break unexpectedly when new base image versions are released. Which Dockerfile practice best addresses this concern?

Use `FROM ubuntu:latest` to always get the newest updates

Use `FROM ubuntu` without a tag

Use `FROM scratch` and manually install all dependencies

Use a specific tag for the base image, such as `FROM ubuntu:20.04`

What is the purpose of a `.dockerignore` file?

To define environment variables for the container

To exclude files and directories from the build context

To list the ports that should be exposed

To specify the base image for the build

CiscoCertified Network Associate Automation (CCNA Automation)

Domain 4Objective 6

6. Interpret Contents of a Dockerfile 200-901 Practice Questions (Page 6)

Part of the 4.0 Application Deployment and Security domain, which accounts for 15% of the 200-901 exam. Cisco does not publish an official question count, but from its 120-minute exam (~50–80 total, ~8–12 in this domain), expect 1–1 from this objective — we provide 43 practice questions to prepare you well beyond it. (estimate)

43questions here

9free pages

12concepts

15%of the exam

Questions 26–30

26application · medium
A developer is building a Docker image for a web application. The build context contains a large node_modules directory and a .env file with production secrets. The developer wants to copy only the application source code into the image and avoid sending unnecessary files to the Docker daemon. Which approach is correct?
Select an answer first
27expert · hard
A team is building a Docker image for a production application. They want to ensure that the image is reproducible and that builds do not break unexpectedly when new base image versions are released. Which Dockerfile practice best addresses this concern?
Select an answer first
28foundation · easy
Which Dockerfile instruction is used to declare the base image for the build?
Select an answer first
29foundation · easy
What is the purpose of a `.dockerignore` file?
Select an answer first
30application · medium
A containerized web service listens on TCP port 8443. The Dockerfile should document this port so that other developers know which port to publish. Which instruction should be used?
Select an answer first

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6. Interpret Contents of a Dockerfile 200-901 Practice Questions (Page 6)

Questions 26–30

A team is building a Docker image for a production application. They want to ensure that the image is reproducible and that builds do not break unexpectedly when new base image versions are released. Which Dockerfile practice best addresses this concern?

Which Dockerfile instruction is used to declare the base image for the build?

What is the purpose of a `.dockerignore` file?

A containerized web service listens on TCP port 8443. The Dockerfile should document this port so that other developers know which port to publish. Which instruction should be used?

Keep studying — 4.0 Application Deployment and Security