DevOps Docker & Containerization

Question 1

What is a Docker image?

Accepted Answer

A read-only template used to create Docker containers

Answer

A running instance of a containerized application

Answer

A virtual machine snapshot for cloud deployments

Answer

A configuration file that defines container networking

Question 2

Which Dockerfile instruction sets the base image for a build?

Accepted Answer

FROM

Answer

BASE

Answer

IMAGE

Answer

ORIGIN

Question 3

What command builds a Docker image from a Dockerfile in the current directory?

Accepted Answer

docker build .

Answer

docker create .

Answer

docker run .

Answer

docker make .

Question 4

What is the difference between a Docker container and a Docker image?

Accepted Answer

A container is a running instance of an image; an image is a static template

Answer

A container is stored on disk while an image runs in memory

Answer

A container can be shared on Docker Hub but an image cannot

Answer

A container includes the OS kernel while an image does not

Question 5

Which Docker networking driver allows containers on the same host to communicate using container names?

Accepted Answer

bridge

Answer

host

Answer

none

Answer

overlay

Question 6

What does the EXPOSE instruction in a Dockerfile do?

Accepted Answer

Documents which port the container listens on at runtime

Answer

Automatically publishes the port to the host machine

Answer

Opens a firewall rule for the specified port

Answer

Maps the container port to a host port