Docker MCQ Questions with answers and solutions Page 36

Q. What command builds an image using a Dockerfile?

(A) docker run
(B) docker image create
(C) docker build
(D) docker make

💬 Discuss

✅ Correct Answer: (C) docker build

Explanation: `docker build` is used to create images from a Dockerfile.

Published by Mr. Dubey ⭐ 111.54K Points at 24-Jul-2025 07:07 am in Docker

Q. What does each line in a Dockerfile represent?

(A) A new container
(B) A new file
(C) A new layer
(D) A new variable

💬 Discuss

✅ Correct Answer: (C) A new layer

Explanation: Each instruction adds a new image layer.

Published by Mr. Dubey ⭐ 111.54K Points at 24-Jul-2025 07:07 am in Docker

Q. What flag skips the cache when building a Docker image?

(A) --skip-cache
(B) --no-cache
(C) --build-clean
(D) --ignore-cache

💬 Discuss

✅ Correct Answer: (B) --no-cache

Explanation: `--no-cache` ensures Docker doesn’t use any cached layers.

Published by Mr. Dubey ⭐ 111.54K Points at 24-Jul-2025 07:07 am in Docker

Q. What is the default shell used by `RUN` in a Dockerfile?

(A) bash
(B) zsh
(C) /bin/sh -c
(D) /bin/bash

💬 Discuss

✅ Correct Answer: (C) /bin/sh -c

Explanation: The default shell for `RUN` is `/bin/sh -c` unless overridden.

Published by Mr. Dubey ⭐ 111.54K Points at 24-Jul-2025 07:07 am in Docker

Q. Which instruction is used to configure the container at runtime?

(A) ENV
(B) RUN
(C) CMD
(D) LABEL

💬 Discuss

✅ Correct Answer: (C) CMD

Explanation: `CMD` configures the command to run at container runtime.

Published by Mr. Dubey ⭐ 111.54K Points at 24-Jul-2025 07:07 am in Docker

Q. What should you do to reduce image size?

(A) Use multiple RUN statements
(B) Use base image with GUI
(C) Use multi-stage builds
(D) Use MAINTAINER

💬 Discuss

✅ Correct Answer: (C) Use multi-stage builds

Explanation: Multi-stage builds help separate build tools from the final image.

Published by Mr. Dubey ⭐ 111.54K Points at 24-Jul-2025 07:07 am in Docker

Q. Can a Dockerfile contain comments?

(A) No
(B) Yes, using //
(C) Yes, using #
(D) Yes, using ;

💬 Discuss

✅ Correct Answer: (C) Yes, using #

Explanation: Comments in Dockerfiles begin with `#`.

Published by Mr. Dubey ⭐ 111.54K Points at 24-Jul-2025 07:07 am in Docker

Q. Which instruction should be placed at the beginning of a Dockerfile?

(A) CMD
(B) RUN
(C) COPY
(D) FROM

💬 Discuss

✅ Correct Answer: (D) FROM

Explanation: `FROM` must be the first instruction in any valid Dockerfile.

Published by Mr. Dubey ⭐ 111.54K Points at 24-Jul-2025 07:07 am in Docker

Q. What is a Docker volume primarily used for?

(A) Networking
(B) Data persistence
(C) Container orchestration
(D) Image optimization

💬 Discuss

✅ Correct Answer: (B) Data persistence

Explanation: Docker volumes are used to persist data generated and used by Docker containers.

Published by Mr. Dubey ⭐ 111.54K Points at 24-Jul-2025 07:12 am in Docker

Q. Which command is used to create a Docker volume?

(A) docker create volume
(B) docker volume new
(C) docker volume create
(D) docker volume init

💬 Discuss

✅ Correct Answer: (C) docker volume create

Explanation: The `docker volume create` command is used to create a new volume.

Published by Mr. Dubey ⭐ 111.54K Points at 24-Jul-2025 07:12 am in Docker

Docker MCQs with answers Page - 36

Q. What command builds an image using a Dockerfile?

Q. What does each line in a Dockerfile represent?

Q. What flag skips the cache when building a Docker image?

Q. What is the default shell used by `RUN` in a Dockerfile?

Q. Which instruction is used to configure the container at runtime?

Q. What should you do to reduce image size?

Q. Can a Dockerfile contain comments?

Q. Which instruction should be placed at the beginning of a Dockerfile?

Q. What is a Docker volume primarily used for?

Q. Which command is used to create a Docker volume?

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