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 compile code faster
2
To containerize applications for portability and efficiency
3
To create virtual machines
4
To manage physical servers
Question 2
Which command is used to list all running Docker containers?
1
docker list
2
docker run
3
docker ps
4
docker images
Question 3
What is the default network driver used by Docker containers?
1
Host
2
Overlay
3
None
4
Bridge
Question 4
Which file is used to define multi-container Docker applications?
1
Docker.yaml
2
Dockerfile
3
Containerfile
4
docker-compose.yml
Question 5
What is the primary purpose of a Dockerfile?
1
To store container logs
2
To create and build Docker images
3
To run database services
4
To define system dependencies
Question 6
Which command is used to remove a stopped container?
1
docker remove <container_id>
2
docker rm <container_id>
3
docker rmi <container_id>
4
docker stop <container_id>
Question 7
How do you start an interactive shell inside a running container?
1
docker shell <container_id>
2
docker run -it <container_id>
3
docker exec -it <container_id> /bin/bash
4
docker attach <container_id>
Question 8
What is the difference between docker stop and docker kill?
1
docker stop immediately kills the container, while docker kill sends a termination signal
2
docker stop sends a graceful termination signal, while docker kill forcefully stops the container
3
They are identical commands
4
docker kill can only be used on stopped containers
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 delete <image_id>
2
docker image prune
3
docker remove image <image_id>
4
docker rmi <image_id>
Question 11
What is a Docker image?
1
A virtual machine
2
A running instance of a container
3
A backup file for Docker
4
A template used to create Docker containers
Question 12
Which Dockerfile instruction sets the base image?
1
CMD
2
FROM
3
BASE
4
RUN
Question 13
What does the docker build command do?
1
Downloads an image
2
Starts a new container
3
Pushes an image to Docker Hub
4
Creates a container image from a Dockerfile
Question 14
What is Docker Hub?
1
A dashboard tool
2
A local storage for containers
3
An IDE for Docker
4
A cloud-based repository for Docker images
Question 15
What is the purpose of the EXPOSE instruction in a Dockerfile?
1
Opens a port in the Docker host firewall
2
Runs a command on a specific port
3
Documents the port the container listens on
4
Maps container ports to the host
Question 16
Which command is used to push a Docker image to Docker Hub?
1
docker save
2
docker upload
3
docker push
4
docker export
Question 17
What is the function of CMD in a Dockerfile?
1
Installs system packages
2
Builds the image
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
Deletes all logs
3
Shows real-time logs from the container’s stdout and stderr
4
Lists running containers
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 cannot run on Windows
4
Containers are slower than virtual machines
Question 20
What does docker-compose up do?
1
Installs Docker
2
Removes all containers
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
The host directory overwrites the container directory
2
Data is merged
3
Docker throws an error
4
The container's data is preserved
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 is faster than COPY
2
COPY is older than ADD
3
ADD can fetch remote URLs and unpack archives
4
No difference
Question 24
Which of the following best describes a multi-stage Docker build?
1
Running multiple build commands at once
2
Combining multiple base images in one build
3
Using one Dockerfile with multiple FROM instructions
4
Using multiple containers in parallel
Question 25
You want to ensure a container restarts if it crashes. Which restart policy should you use?
1
always
2
no
3
unless-stopped
4
on-failure
Question 26
What’s the purpose of .dockerignore file?
1
It disables Dockerfile execution
2
It hides logs
3
It prevents files from being copied to the host
4
It excludes files from image build context
Question 27
What does the ENTRYPOINT instruction do differently from CMD?
1
It sets the main command that cannot be replaced by arguments
2
It is overridden by Docker run arguments
3
It cannot be changed
4
It runs only once
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 -e -d ENV=production image
3
docker start -e 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 Network
3
Docker Swarm
4
Docker Compose
Question 30
What does the --mount flag provide that -v (volume) does not?
1
Container restart on change
2
Named volumes
3
Read-only support
4
Clear syntax and extra options like consistency and caching