Docker Container Basics for DevOps

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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

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6. 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

7. Which command lists all running containers?

Docker images

Docker ps

Docker logs

Docker stats

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9. 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

10. Which layer in a Docker image is writable?

The base layer

All layers are writable

The container layer

Docker images have no writable layers

11. 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

12. 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

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

Bridge

Host

Overlay

None

14. 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

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

Docker Hub

Amazon ECR

Google Container Registry

GitLab Container Registry

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17. 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

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

Docker build

Docker run

Docker pull

Docker push

19. 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

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

Docker Engine

Docker Image

Docker Registry

Docker Daemon

General DevOps Intermediate Container Basics with Docker Quiz

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

2.

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

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

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

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

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

6. What is a Docker layer?

7. Which command lists all running containers?

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

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

10. Which layer in a Docker image is writable?

11. What is a Docker container?

12. What does Docker Compose allow you to do?

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

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

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

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

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

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

19. What is the primary purpose of a Dockerfile?

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