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 compile code faster
3
To containerize applications for portability and efficiency
4
To manage physical servers
Question 2
Which command is used to list all running Docker containers?
1
docker list
2
docker images
3
docker run
4
docker ps
Question 3
What is the default network driver used by Docker containers?
1
None
2
Bridge
3
Host
4
Overlay
Question 4
Which file is used to define multi-container Docker applications?
1
docker-compose.yml
2
Dockerfile
3
Containerfile
4
Docker.yaml
Question 5
What is the primary purpose of a Dockerfile?
1
To define system dependencies
2
To create and build Docker images
3
To run database services
4
To store container logs
Question 6
Which command is used to remove a stopped container?
1
docker stop <container_id>
2
docker rmi <container_id>
3
docker rm <container_id>
4
docker remove <container_id>
Question 7
How do you start an interactive shell inside a running container?
1
docker run -it <container_id>
2
docker shell <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
They are identical commands
2
docker kill can only be used on stopped containers
3
docker stop immediately kills the container, while docker kill sends a termination signal
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
Automating deployments
2
Running multiple containers
3
Managing container logs
4
Storing persistent data outside of containers
Question 10
How do you remove an unused Docker image?
1
docker delete <image_id>
2
docker rmi <image_id>
3
docker remove image <image_id>
4
docker image prune
Question 11
What is a Docker image?
1
A backup file for Docker
2
A running instance of a container
3
A virtual machine
4
A template used to create Docker containers
Question 12
Which Dockerfile instruction sets the base image?
1
BASE
2
RUN
3
FROM
4
CMD
Question 13
What does the docker build command do?
1
Creates a container image from a Dockerfile
2
Pushes an image to Docker Hub
3
Downloads an image
4
Starts a new container
Question 14
What is Docker Hub?
1
A cloud-based repository for Docker images
2
An IDE for Docker
3
A dashboard tool
4
A local storage for containers
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
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 push
2
docker upload
3
docker export
4
docker save
Question 17
What is the function of CMD in a Dockerfile?
1
Builds the image
2
Declares environment variables
3
Specifies the command to run when a container starts
4
Installs system packages
Question 18
What does docker logs <container> do?
1
Opens a shell inside the container
2
Deletes all logs
3
Lists running containers
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
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 container's data is preserved
2
Docker throws an error
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
host
3
bridge
4
macvlan
Question 23
What is the difference between COPY and ADD in a Dockerfile?
1
ADD is faster than COPY
2
No difference
3
ADD can fetch remote URLs and unpack archives
4
COPY is older than ADD
Question 24
Which of the following best describes a multi-stage Docker build?
1
Using one Dockerfile with multiple FROM instructions
2
Combining multiple base images in one build
3
Running multiple build commands at once
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
on-failure
3
unless-stopped
4
no
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 cannot be changed
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 -e -d ENV=production image
2
docker run -d ENV=production image
3
docker run --detach --env ENV=production image
4
docker start -e ENV=production image
Question 29
Which component is used for orchestrating multi-host Docker deployments?
1
Docker Compose
2
Docker Machine
3
Docker Swarm
4
Docker Network
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