Docker Container Basics for DevOps

1. What is a Docker container?

A lightweight, portable executable package containing code and dependencies

A virtual machine running a full operating system

A cloud storage service for Docker images

A version control system for application code

2. What is the primary purpose of a Dockerfile?

To define instructions for building a Docker image

To manage container networking

To monitor container performance

To authenticate users to Docker Hub

3. What does the EXPOSE instruction in a Dockerfile do?

Documents which ports the container listens on

Opens ports to external traffic

Encrypts communication on specified ports

Binds the container to a host port

4. Which best practice reduces Docker image size and improves security?

Using a minimal base image and removing unnecessary files

Installing all possible packages upfront

Running containers as root user

Avoiding multi-stage builds

Submit

7. What is the difference between ENTRYPOINT and CMD in a Dockerfile?

ENTRYPOINT configures the container as executable; CMD provides default arguments

They are identical and interchangeable

ENTRYPOINT is deprecated in favor of CMD

CMD defines the base image; ENTRYPOINT defines the process

8. Which Docker networking driver is suitable for multi-host communication?

Bridge

Host

Overlay

None

9. What does Docker Compose allow you to do?

Define and run multi-container applications using a YAML file

Compile Docker source code

Compress Docker images

Communicate between Docker registries

Submit

11. What is a Docker layer?

A read-only filesystem snapshot created during image build

A network configuration setting

A security feature for access control

A backup copy of the container

12. What is the purpose of mounting a volume in Docker?

To persist data outside the container filesystem

To increase container CPU

To encrypt container communication

To reduce image size

Submit

14. Which component of Docker stores the blueprint for creating containers?

Docker Engine

Docker Image

Docker Registry

Docker Daemon

15. Which command lists all running containers?

Docker images

Docker ps

Docker logs

Docker stats

16. Which layer in a Docker image is writable?

The base layer

All layers are writable

The container layer

Docker images have no writable layers

17. Which registry is the default public repository for Docker images?

Docker Hub

Amazon ECR

Google Container Registry

GitLab Container Registry

18. Which command creates a new container from an image?

Docker build

Docker run

Docker pull

Docker push

19. What does the FROM instruction in a Dockerfile specify?

The base image to build upon

The port to expose

The working directory inside the container

The environment variables to set

Submit

General DevOps Intermediate Container Basics with Docker Quiz

1. What is a Docker container?

2.

What first name or nickname would you like us to use?

2. What is the primary purpose of a Dockerfile?

3. What does the EXPOSE instruction in a Dockerfile do?

4. Which best practice reduces Docker image size and improves security?

5. Docker containers are ______ in nature, meaning they can run consistently across different environments.

6. Docker uses ______ isolation to provide lightweight, secure separation between containers.

7. What is the difference between ENTRYPOINT and CMD in a Dockerfile?

8. Which Docker networking driver is suitable for multi-host communication?

9. What does Docker Compose allow you to do?

10. A Docker ______ is a running instance of an image with its own isolated filesystem and processes.

11. What is a Docker layer?

12. What is the purpose of mounting a volume in Docker?

13. The Docker ______ is responsible for managing images, containers, networks, and storage.

14. Which component of Docker stores the blueprint for creating containers?

15. Which command lists all running containers?

16. Which layer in a Docker image is writable?

17. Which registry is the default public repository for Docker images?

18. Which command creates a new container from an image?

19. What does the FROM instruction in a Dockerfile specify?

20. Container ______ allows you to define resource limits such as CPU and memory for containers.