Quiz: QZ-20251028-30315

Quiz Details

QZ-20251028-30315

Topics:

Dockerfile

Difficulty: Level 3 - Medium

Questions: 10

Generated: October 28, 2025 at 10:39 AM

Generated by: Elli Watson

Instructions: Select an answer for each question and click "Check Answer" to see if you're correct. Then view the explanation to learn more!

1 What is the purpose of a Dockerfile?

A) To manage container orchestration.

B) To monitor container performance.

C) To create a container from an existing image.

D) To define the environment and instructions for building a Docker image.

Correct Answer: D
Explanation: A Dockerfile contains a series of instructions that specify how to build a Docker image, including the base image, environment variables, and commands to run.

2 Which command is used to build a Docker image from a Dockerfile?

A) docker build

B) docker run

C) docker image

D) docker create

Correct Answer: A
Explanation: The 'docker build' command is used to create a Docker image from the instructions specified in a Dockerfile.

3 In a Dockerfile, which instruction is used to copy files from the host to the Docker image?

A) ADD

B) IMPORT

C) COPY

D) FETCH

Correct Answer: C
Explanation: The 'COPY' instruction is used to copy files and directories from the host file system into the Docker image.

4 What does the FROM instruction in a Dockerfile do?

A) Sets environment variables for the image.

B) Defines the command to run when the container starts.

C) Specifies the base image to use for the Docker image.

D) Installs software packages.

Correct Answer: C
Explanation: The 'FROM' instruction specifies the base image for the new image being built, which serves as the starting point.

5 Which instruction would you use to execute a command in a Dockerfile during the build process?

A) RUN

B) EXEC

C) EXECUTE

D) CMD

Correct Answer: A
Explanation: The 'RUN' instruction is used to execute commands in a Dockerfile during the image build process, allowing you to install packages or modify the file system.

6 What is the difference between CMD and ENTRYPOINT in a Dockerfile?

A) CMD is used to specify the image base.

B) CMD sets default arguments for ENTRYPOINT.

C) ENTRYPOINT can be overridden by CMD.

D) There is no difference; they are interchangeable.

Correct Answer: B
Explanation: The 'CMD' instruction provides default arguments for the 'ENTRYPOINT' instruction, and it can be overridden when the container is run.

7 What does the EXPOSE instruction do in a Dockerfile?

A) Defines the memory limits for the container.

B) Creates a network for the container.

C) Exposes a port for the container to communicate.

D) Removes a port from the container.

Correct Answer: C
Explanation: The 'EXPOSE' instruction informs Docker that the container will listen on the specified network ports at runtime, allowing for communication with other containers or services.

8 Which of the following is NOT a valid instruction in a Dockerfile?

A) COPY

B) BUILD

C) FROM

D) RUN

Correct Answer: B
Explanation: There is no 'BUILD' instruction in a Dockerfile. Valid instructions include 'COPY', 'RUN', and 'FROM'.

9 What is the purpose of the VOLUME instruction in a Dockerfile?

A) To create a persistent storage location for the container.

B) To increase the image size.

C) To specify build arguments.

D) To define a network interface.

Correct Answer: A
Explanation: The 'VOLUME' instruction is used to create a mount point with the specified path and to enable data persistence by allowing data to be stored outside the container.

10 How can you specify build arguments in a Dockerfile?

A) Using the ARG instruction.

B) Using the ENV instruction.

C) Using the OPTIONS instruction.

D) Using the SET instruction.

Correct Answer: A
Explanation: The 'ARG' instruction allows you to define variables that users can pass at build-time to the Dockerfile, enabling dynamic image builds.

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