Docker Questions and Exercises

Docker Questions and Exercises

The objective of all these questions is to bring docker commands into hands on practice.

Which of the following statements about VMs and Docker containers are not valid?

a. Virtual Machine contains the entire Operating System.

b. Docker containers use the resource of the host operating system.

c. Docker containers are used when multiple applications need to run on the same host.

d. Virtual Machines and Docker Containers are the same things.

Which of the following are true about Container creation from the docker image?

a. Each Docker container is assigned a universally unique identifier (UUID).

b. Container creation, Docker allows us to set container names using the name flag.

c. If you do not specify the Container name, docker supplies a randomly-generated name from two words, joined by an underscore.

Which of the following are the advantages of Container Orchestration?

a. Scaling up or removing containers to spread application load

b. Movement of containers from one resource to another

c. Load balancing of service discovery between containers

d. Health monitoring of containers and hosts

Choose the correct statements for the following command. — — — — —  “docker image prune”

a. command allows us to clean up unused images.

b. By default, the above command will only clean up dangling images.

c. Dangling Image is an Image without Tags and not referenced by any container

d. All of the above

Which of the following is not a valid docker CLI command?

a. docker image build

b. docker image history

c. docker image import

d. docker image inspect

e. docker image delete

What is the default Network Type in Docker?

a. bridge

b. host

c. overlay

d. macvlan

Which of the following is not a valid Docker Instruction?


b. RUN

c. CMD



Choose the incorrect statements from the following.

a. Multiple containers can be started using the same image.

b. Docker Image is immutable

c. Docker Container has a Top Layer which is writable

d. Docker Container and Docker Images are the same things

Which of the following flag is not valid while using HEALTHCHECK instruction?

a. interval=DURATION

b. timeout=DURATION

c. start-period=DURATION

d. retries=N (default: 3)

e. All are valid

Pick the default docker container restart policy.

a. none

b. always

c. on-failure

d. unless-stopped

Which of the following commands are correct?

a. docker exec -it service-a bash

b. docker run -it service-a sh

c. docker run — env VAR1=value1 — env VAR2=value2 ubuntu env

d. All of the above.

Which of the following namespace is not enabled by default?

a. volume

b. network

c. pid

d. user

Write the docker commands to perform the following:

  1. List all docker images

  2. List all running docker containers

  1. List all containers which are in exited state
  1. Tag a docker image
  1. Push an image to docker repository
  1. List all dangling images
  1. Delete all dangling images

What is the difference between the below commands?

A. docker rmi $(docker images -a — filter=dangling=true -q)

B.docker rmi $(docker images -f dangling=true -q)

Which of the following instructions will optimise the size of the image and why?

Instruction 1::

ADD /mnt/data

RUN tar -xJf /mnt/data/abc.tar /mnt/data

RUN make -C /mnt/data all

Instruction 2::

RUN mkdir -p /mnt/data \

&& curl -SL \

| tar -xJf /mnt/data \

&& make -C /mnt/data all

Which of the following are true about Docker Secrets?

a. Secret can be modified

b. Secret can only be excited on docker-swarm management console

c. Can’t renamed or update to docker secret

By default docker container is privileged or unprivileged?

What is the difference between docker save and docker export commands?

Which flag will be used for automatically removing a Container?

Write a docker command to run a container with volume mounted as /mnt/mydata?

What is the difference between COPY and ADD commands?

What is the difference between CMD and ENTRYPOINT instruction?

What is the difference between docker filter and format commands?

Which file can customise the DNS settings of the container?

What is the difference between Limit and Reservation?

I’ll be sharing the GitHub link with answers as well, feel free to reach out to me.