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 manage physical servers
2
To create virtual machines
3
To compile code faster
4
To containerize applications for portability and efficiency
Question 2
Which command is used to list all running Docker containers?
1
docker ps
2
docker images
3
docker run
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
Containerfile
4
Dockerfile
Question 5
What is the primary purpose of a Dockerfile?
1
To define system dependencies
2
To store container logs
3
To run database services
4
To create and build Docker images
Question 6
Which command is used to remove a stopped container?
1
docker remove <container_id>
2
docker stop <container_id>
3
docker rm <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 shell <container_id>
4
docker exec -it <container_id> /bin/bash
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
Storing persistent data outside of containers
2
Running multiple containers
3
Automating deployments
4
Managing container logs
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 template used to create Docker containers
2
A virtual machine
3
A backup file for Docker
4
A running instance of a container
Question 12
Which Dockerfile instruction sets the base image?
1
RUN
2
FROM
3
CMD
4
BASE
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
Downloads an image
4
Starts a new container
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
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 upload
2
docker push
3
docker save
4
docker export
Question 17
What is the function of CMD in a Dockerfile?
1
Declares environment variables
2
Installs system packages
3
Builds the image
4
Specifies the command to run when a container starts
Question 18
What does docker logs <container> do?
1
Shows real-time logs from the container’s stdout and stderr
2
Deletes all logs
3
Opens a shell inside the container
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 cannot run on Windows
3
Containers are slower than virtual machines
4
Containers share the host OS kernel
Question 20
What does docker-compose up do?
1
Pulls images from Docker Hub without starting them
2
Builds and starts all services defined in docker-compose.yml
3
Removes all containers
4
Installs Docker
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
The container's data is preserved
4
Docker throws an error
Question 22
Which networking mode allows Docker containers to share the host’s network stack?
1
bridge
2
macvlan
3
overlay
4
host
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
No difference
4
ADD is faster than COPY
Question 24
Which of the following best describes a multi-stage Docker build?
1
Using multiple containers in parallel
2
Combining multiple base images in one build
3
Using one Dockerfile with multiple FROM instructions
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
on-failure
2
always
3
unless-stopped
4
no
Question 26
What’s the purpose of .dockerignore file?
1
It excludes files from image build context
2
It disables Dockerfile execution
3
It prevents files from being copied to the host
4
It hides logs
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 -d ENV=production image
2
docker run -e -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 Machine
2
Docker Swarm
3
Docker Network
4
Docker Compose
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