Docker Questions

Vikas Vimal (Vikki)

Score: 🔥 175

Beginner

Took 2 months

Software Tool

Docker

86%

Questions Attempted

15 / 15

Correct Answers

Incorrect Answers

Points Earned

🔥 13

Question 1

If you launch a container with '--network none' and later need to give it network access, what should you do?

You cannot change the network mode once a container is created, you must recreate it
Use the 'docker network connect' command to attach the container to an existing network
Restart the container with the desired network mode specified
Modify the container's configuration files to add network settings

Explanation:

You can dynamically add or remove a container from a network using 'docker network connect' and 'docker network disconnect' even after the container is created.

Question 2

What is a Docker image?

A running instance of a container
A template for creating Docker containers
A repository for storing Docker containers
A command-line tool for managing Docker containers

Explanation:

A Docker image serves as a blueprint containing the application code, libraries, dependencies, and configurations needed to create a Docker container.

Question 3

What's the purpose of the -d flag when running a Docker container?

Delete the container automatically after it exits.
Run the container in detached mode (background).
Display detailed logs from the container.
Disable networking for the container.

Explanation:

-d stands for 'detached'. When you use this flag, the container runs in the background, freeing up your terminal.

Question 4

When should you consider using the 'host' network mode for a Docker container?

When you need to run a network monitoring tool inside the container
When you want to limit the container's network access for security reasons
When you need to expose multiple ports from the container
When you want to connect the container to a specific VLAN on the host

Explanation:

The 'host' mode allows the container to directly access the host's network interfaces and observe all network traffic, making it suitable for network monitoring tools.

Question 5

What is the core functionality of Docker?

Managing virtual machines
Automating software deployments
Building and running applications in isolated environments
Compiling code into executable programs

Explanation:

Docker specializes in creating lightweight, portable environments called containers. These containers encapsulate applications and their dependencies, making them runnable on various systems without compatibility issues.

Question 6

What is the primary purpose of Docker?

To manage hardware resources efficiently
To package and run applications in isolated environments
To provide a platform for running virtual machines
To automate software testing processes

Explanation:

Docker's core function is to package applications and their dependencies into containers, creating consistent and isolated environments for development, testing, and deployment.

Question 7

What is the primary purpose of Docker containers in software development?

To create virtual machines.
To package and isolate applications with their dependencies.
To manage network infrastructure.
To compile code faster.

Explanation:

Docker containers encapsulate applications and their dependencies, providing a consistent and isolated environment across different systems. This isolation and portability enhance development, testing, and deployment workflows.

Question 8

Which command is used to download a Docker image from a registry?

docker pull
docker push
docker run
docker build

Explanation:

The docker pull command retrieves an image from a registry, such as Docker Hub, and stores it locally for later use in creating containers.

Question 9

Which component of Docker's architecture is responsible for building and storing Docker images?

Docker Client
Docker Host
Docker Registry
Docker Container

Explanation:

Docker Registries, like Docker Hub, act as repositories for Docker images. They allow developers to store and share pre-built images, simplifying application deployment.

Question 10

Which file format does Docker Compose use for defining application services?

Dockerfile
docker-compose.yml
compose.json
config.yaml

Explanation:

Docker Compose relies on a YAML file named 'docker-compose.yml' to describe the services, networks, and volumes that make up your application. YAML's human-readable format makes it well-suited for this purpose.

Question 11

How do you list all running Docker containers?

docker ps -a
docker run -it
docker images
docker ps

Explanation:

The command 'docker ps' provides a list of all actively running containers on your system. The '-a' flag would show all containers, including stopped ones.

Question 12

Which command is used to create and start a Docker container?

docker build
docker run
docker start
docker create

Explanation:

The docker run command is a combined operation. It first creates a new container from a specified image and then starts that container.

Question 13

What does the '-d' flag do when running a Docker container?

Deletes the container after it stops.
Runs the container in detached mode (background).
Downloads the latest image from the repository.
Displays the container's logs in the terminal.

Explanation:

The -d flag stands for 'detached.' It instructs Docker to run the container in the background, keeping your terminal session free.

Question 14

In a 'docker-compose.yml' file, what is the keyword used to define a service?

container
image
service
app

Explanation:

The 'service' keyword is the fundamental building block in a 'docker-compose.yml' file. Each service you define represents a container or a set of containers that work together.

Question 15

After stopping a container, you want to remove it completely. What command should you use?

docker remove
docker delete
docker rm
docker erase

Explanation:

docker rm is used to remove a container. Note: The container must be stopped before it can be removed.