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