Docker Certified Associate (DCA) Practice Questions: Installation and Configuration Domain

Docker Certified Associate (DCA) Practice Questions

Master the Installation and Configuration Domain

Test your knowledge in the Installation and Configuration domain with these 10 practice questions. Each question is designed to help you prepare for the DCA certification exam with detailed explanations to reinforce your learning.

Question 1

How would you configure Docker to use a custom DNS server for container name resolution?

A) Add "dns": ["8.8.8.8"] to /etc/docker/daemon.json

B) Use the command 'docker dns set 8.8.8.8'

C) Modify the /etc/resolv.conf file

D) Set the DNS server in the Dockerfile with 'DNS 8.8.8.8'

Show Answer & Explanation

Correct Answer: A

Explanation: To configure Docker to use a custom DNS server, you add "dns": ["8.8.8.8"] to the '/etc/docker/daemon.json' file. This setting will apply to all containers started by the Docker daemon. Option B is incorrect as there is no such command as 'docker dns set'. Option C is incorrect because modifying '/etc/resolv.conf' affects the host DNS resolution, not Docker containers specifically. Option D is incorrect because DNS settings cannot be specified in a Dockerfile.

Question 2

After installing Docker on a Linux server, you want to allow a user to manage Docker without using 'sudo'. What is the recommended way to achieve this?

A) Add the user to the 'docker' group

B) Grant the user root privileges

C) Change Docker's socket permissions to be world-readable

D) Add the user to the 'sudo' group

Show Answer & Explanation

Correct Answer: A

Explanation: The recommended way to allow a user to manage Docker without using 'sudo' is to add the user to the 'docker' group. This grants the user permissions to interact with the Docker daemon. Option B is incorrect because granting root privileges is not necessary and poses a security risk. Option C is incorrect because changing the socket permissions to be world-readable can lead to security vulnerabilities. Option D is incorrect because adding the user to the 'sudo' group still requires using 'sudo' to execute Docker commands.

Question 3

How can you configure Docker to listen on a specific IP address and port for incoming connections?

A) Edit the /etc/docker/daemon.json file and set the 'hosts' key

B) Use the command 'docker configure --ip= --port='

C) Set environment variables DOCKER_HOST_IP and DOCKER_HOST_PORT

D) Modify the /etc/hosts file with the Docker IP and port

Show Answer & Explanation

Correct Answer: A

Explanation: To configure Docker to listen on a specific IP address and port, you should edit the '/etc/docker/daemon.json' file and set the 'hosts' key with the desired IP and port. Option B is incorrect because 'docker configure' is not a valid Docker command. Option C is incorrect as Docker does not use these environment variables for this purpose. Option D is incorrect because modifying '/etc/hosts' does not configure Docker daemon settings.

Question 4

You are tasked with installing Docker on a new Ubuntu server. Which of the following commands should you run first to ensure your package information is up to date before installing Docker?

A) sudo apt-get install docker-ce

B) sudo apt-get update

C) sudo apt-get upgrade

D) sudo apt-get install docker-ce docker-ce-cli containerd.io

Show Answer & Explanation

Correct Answer: B

Explanation: Before installing new packages on an Ubuntu system, it's best practice to run 'sudo apt-get update' to ensure that your package list is up to date. This command updates the list of available packages and their versions, but it does not install or upgrade any packages. Option A and D are commands for installing Docker, and C upgrades installed packages, which is not necessary before updating the package list.

Question 5

When installing Docker on a Linux system, which command is used to add the Docker repository to your package manager?

A) sudo apt-get install docker-repo

B) curl -fsSL https://get.docker.com/ | sh

C) sudo add-apt-repository 'deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable'

D) sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

Show Answer & Explanation

Correct Answer: C

Explanation: Option C is the correct command to add the Docker repository for Ubuntu systems to the package manager. Option A is incorrect because it is not a valid command for adding a repository. Option B is a script to install Docker directly, not just add the repository. Option D is for CentOS, not Ubuntu.

Question 6

Which command is used to reload the Docker daemon configuration without restarting the Docker service?

A) docker reload

B) systemctl reload docker

C) kill -SIGHUP $(pidof dockerd)

D) docker service reload

Show Answer & Explanation

Correct Answer: C

Explanation: The 'kill -SIGHUP $(pidof dockerd)' command sends a SIGHUP signal to the Docker daemon, prompting it to reload its configuration without restarting. Option A is incorrect because 'docker reload' is not a valid command. Option B is incorrect because 'systemctl reload docker' is not typically used for Docker. Option D is incorrect because 'docker service reload' is not a valid command.

Question 7

Which command is used to install Docker on a CentOS system using the yum package manager?

A) yum install docker

B) yum install docker-ce

C) yum install docker-ce-cli

D) yum install docker-engine

Show Answer & Explanation

Correct Answer: B

Explanation: The command 'yum install docker-ce' is used to install Docker CE on a CentOS system. Option A is incorrect because it refers to an outdated package. Option C installs only the Docker CLI, not the full Docker package. Option D is incorrect because 'docker-engine' is an older package no longer used.

Question 8

Which of the following is a valid method to configure Docker to listen on a specific network interface?

A) Modify the /etc/docker/interfaces file

B) Set the DOCKER_OPTS variable in /etc/default/docker

C) Use the 'docker network connect' command

D) Edit the ExecStart line in the systemd service file for Docker

Show Answer & Explanation

Correct Answer: D

Explanation: The correct answer is D. Editing the ExecStart line in the systemd service file for Docker allows you to specify options such as network interfaces for the Docker daemon. Option A is incorrect because there is no such file. Option B was used in older Docker setups but is not applicable for systemd-based systems. Option C is used to connect containers to networks, not to configure the Docker daemon.

Question 9

Which of the following commands will correctly install Docker on an Ubuntu system?

A) apt-get install docker

B) apt-get install docker-engine

C) apt-get install docker-ce

D) apt-get install docker.io

Show Answer & Explanation

Correct Answer: D

Explanation: On Ubuntu, the package 'docker.io' is used to install Docker. Option A is incorrect because 'docker' is not a package name. Option B, 'docker-engine', is an outdated package name. Option C, 'docker-ce', is used for installing Docker Community Edition via the Docker repository, not directly through 'apt-get'.

Question 10

What is the correct procedure to adjust the default logging driver for Docker containers globally?

A) Set the logging driver in the Dockerfile

B) Use the command 'docker logging set --driver json-file'

C) Add "log-driver": "json-file" to /etc/docker/daemon.json

D) Configure the logging driver in each container's run command

Show Answer & Explanation

Correct Answer: C

Explanation: To set the default logging driver for all Docker containers globally, you add "log-driver": "json-file" to the '/etc/docker/daemon.json' file. Option A is incorrect because logging drivers cannot be set in a Dockerfile. Option B is incorrect as there is no 'docker logging set' command. Option D is incorrect because configuring the logging driver in each container's run command does not change the global default.

Ready to Accelerate Your DCA Preparation?

Join thousands of professionals who are advancing their careers through expert certification preparation with FlashGenius.

• ✅ Unlimited practice questions across all DCA domains

• ✅ Full-length exam simulations with real-time scoring

• ✅ AI-powered performance tracking and weak area identification

• ✅ Personalized study plans with adaptive learning

• ✅ Mobile-friendly platform for studying anywhere, anytime

• ✅ Expert explanations and study resources

Start Free Practice Now

Already have an account? Sign in here

About DCA Certification

The DCA certification validates your expertise in installation and configuration and other critical domains. Our comprehensive practice questions are carefully crafted to mirror the actual exam experience and help you identify knowledge gaps before test day.

📚 More Docker Certified Associate (DCA) Practice Questions:

• DCA Storage and Volumes – Free Practice Questions (2025)
• DCA Security – Free Practice Questions (2025)
• DCA Networking – Free Practice Questions (2025)
• DCA Orchestration – Free Practice Questions (2025)