Practice docker Quizzes
Explore docker in depth with quizzes covering fundamentals to advanced concepts. DevBrainiac's structured quiz format helps you understand theory, apply logic and master problem-solving techniques. With continuous practice, you can track progress, fix mistakes and build strong command of docker.
Explore All docker Quizzes
Learn docker step by step with interactive quizzes designed for beginners and learners revising key concepts. Build a strong foundation with clear, structured practice in docker.
Question 1
What is the primary purpose of Docker?
1
To containerize applications for portability and efficiency
2
To create virtual machines
3
To compile code faster
4
To manage physical servers
Question 2
Which command is used to list all running Docker containers?
1
docker ps
2
docker run
3
docker images
4
docker list
Question 3
What is the default network driver used by Docker containers?
1
Overlay
2
None
3
Host
4
Bridge
Question 4
Which file is used to define multi-container Docker applications?
1
docker-compose.yml
2
Docker.yaml
3
Dockerfile
4
Containerfile
Question 5
What is the primary purpose of a Dockerfile?
1
To define system dependencies
2
To create and build Docker images
3
To store container logs
4
To run database services
Question 6
Which command is used to remove a stopped container?
1
docker rmi <container_id>
2
docker rm <container_id>
3
docker remove <container_id>
4
docker stop <container_id>
Question 7
How do you start an interactive shell inside a running container?
1
docker run -it <container_id>
2
docker attach <container_id>
3
docker exec -it <container_id> /bin/bash
4
docker shell <container_id>
Question 8
What is the difference between docker stop and docker kill?
1
docker stop sends a graceful termination signal, while docker kill forcefully stops the container
2
docker stop immediately kills the container, while docker kill sends a termination signal
3
docker kill can only be used on stopped containers
4
They are identical commands
Question 9
What is a Docker volume used for?
1
Storing persistent data outside of containers
2
Managing container logs
3
Automating deployments
4
Running multiple containers
Question 10
How do you remove an unused Docker image?
1
docker rmi <image_id>
2
docker remove image <image_id>
3
docker image prune
4
docker delete <image_id>
Question 11
What is a Docker image?
1
A template used to create Docker containers
2
A virtual machine
3
A running instance of a container
4
A backup file for Docker
Question 12
Which Dockerfile instruction sets the base image?
1
CMD
2
BASE
3
RUN
4
FROM
Question 13
What does the docker build command do?
1
Pushes an image to Docker Hub
2
Creates a container image from a Dockerfile
3
Starts a new container
4
Downloads an image
Question 14
What is Docker Hub?
1
An IDE for Docker
2
A local storage for containers
3
A dashboard tool
4
A cloud-based repository for Docker images
Question 15
What is the purpose of the EXPOSE instruction in a Dockerfile?
1
Maps container ports to the host
2
Runs a command on a specific port
3
Opens a port in the Docker host firewall
4
Documents the port the container listens on
Question 16
Which command is used to push a Docker image to Docker Hub?
1
docker export
2
docker upload
3
docker push
4
docker save
Question 17
What is the function of CMD in a Dockerfile?
1
Builds the image
2
Installs system packages
3
Specifies the command to run when a container starts
4
Declares environment variables
Question 18
What does docker logs <container> do?
1
Opens a shell inside the container
2
Lists running containers
3
Deletes all logs
4
Shows real-time logs from the container’s stdout and stderr
Question 19
Which of the following is true about Docker containers?
1
Containers are slower than virtual machines
2
Each container includes a full operating system
3
Containers cannot run on Windows
4
Containers share the host OS kernel
Question 20
What does docker-compose up do?
1
Removes all containers
2
Installs Docker
3
Pulls images from Docker Hub without starting them
4
Builds and starts all services defined in docker-compose.yml
Question 21
What happens if you run a container with a volume and the target folder inside the container already has data?
1
The host directory overwrites the container directory
2
Docker throws an error
3
Data is merged
4
The container's data is preserved
Question 22
Which networking mode allows Docker containers to share the host’s network stack?
1
bridge
2
host
3
overlay
4
macvlan
Question 23
What is the difference between COPY and ADD in a Dockerfile?
1
No difference
2
ADD can fetch remote URLs and unpack archives
3
ADD is faster than COPY
4
COPY is older than ADD
Question 24
Which of the following best describes a multi-stage Docker build?
1
Combining multiple base images in one build
2
Using one Dockerfile with multiple FROM instructions
3
Using multiple containers in parallel
4
Running multiple build commands at once
Question 25
You want to ensure a container restarts if it crashes. Which restart policy should you use?
1
no
2
on-failure
3
unless-stopped
4
always
Question 26
What’s the purpose of .dockerignore file?
1
It excludes files from image build context
2
It hides logs
3
It prevents files from being copied to the host
4
It disables Dockerfile execution
Question 27
What does the ENTRYPOINT instruction do differently from CMD?
1
It cannot be changed
2
It runs only once
3
It sets the main command that cannot be replaced by arguments
4
It is overridden by Docker run arguments
Question 28
How do you run a container in detached mode with an environment variable?
1
docker run --detach --env ENV=production image
2
docker start -e ENV=production image
3
docker run -e -d ENV=production image
4
docker run -d ENV=production image
Question 29
Which component is used for orchestrating multi-host Docker deployments?
1
Docker Machine
2
Docker Swarm
3
Docker Compose
4
Docker Network
Question 30
What does the --mount flag provide that -v (volume) does not?
1
Container restart on change
2
Named volumes
3
Clear syntax and extra options like consistency and caching
4
Read-only support