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 containerize applications for portability and efficiency
3
To manage physical servers
4
To compile code faster
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
Bridge
2
None
3
Overlay
4
Host
Question 4
Which file is used to define multi-container Docker applications?
1
Dockerfile
2
Docker.yaml
3
Containerfile
4
docker-compose.yml
Question 5
What is the primary purpose of a Dockerfile?
1
To run database services
2
To store container logs
3
To define system dependencies
4
To create and build Docker images
Question 6
Which command is used to remove a stopped container?
1
docker stop <container_id>
2
docker rm <container_id>
3
docker remove <container_id>
4
docker rmi <container_id>
Question 7
How do you start an interactive shell inside a running container?
1
docker attach <container_id>
2
docker run -it <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 kill can only be used on stopped containers
2
docker stop immediately kills the container, while docker kill sends a termination signal
3
docker stop sends a graceful termination signal, while docker kill forcefully stops the container
4
They are identical commands
Question 9
What is a Docker volume used for?
1
Running multiple containers
2
Managing container logs
3
Storing persistent data outside of containers
4
Automating deployments
Question 10
How do you remove an unused Docker image?
1
docker delete <image_id>
2
docker rmi <image_id>
3
docker image prune
4
docker remove image <image_id>
Question 11
What is a Docker image?
1
A backup file for Docker
2
A running instance of a container
3
A template used to create Docker containers
4
A virtual machine
Question 12
Which Dockerfile instruction sets the base image?
1
FROM
2
RUN
3
CMD
4
BASE
Question 13
What does the docker build command do?
1
Downloads an image
2
Creates a container image from a Dockerfile
3
Pushes an image to Docker Hub
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 local storage for containers
4
A dashboard tool
Question 15
What is the purpose of the EXPOSE instruction in a Dockerfile?
1
Maps container ports to the host
2
Documents the port the container listens on
3
Opens a port in the Docker host firewall
4
Runs a command on a specific port
Question 16
Which command is used to push a Docker image to Docker Hub?
1
docker upload
2
docker push
3
docker export
4
docker save
Question 17
What is the function of CMD in a Dockerfile?
1
Declares environment variables
2
Installs system packages
3
Specifies the command to run when a container starts
4
Builds the image
Question 18
What does docker logs <container> do?
1
Deletes all logs
2
Shows real-time logs from the container’s stdout and stderr
3
Opens a shell inside the container
4
Lists running containers
Question 19
Which of the following is true about Docker containers?
1
Containers cannot run on Windows
2
Each container includes a full operating system
3
Containers share the host OS kernel
4
Containers are slower than virtual machines
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
Installs Docker
4
Removes all containers
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
The container's data is preserved
3
Docker throws an error
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
No difference
2
ADD is faster than COPY
3
COPY is older than ADD
4
ADD can fetch remote URLs and unpack archives
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
no
3
on-failure
4
unless-stopped
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 is overridden by Docker run arguments
4
It runs only once
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 --detach --env 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 Network
2
Docker Swarm
3
Docker Machine
4
Docker Compose
Question 30
What does the --mount flag provide that -v (volume) does not?
1
Clear syntax and extra options like consistency and caching
2
Container restart on change
3
Named volumes
4
Read-only support