Docker certification

The Ultimate Docker Certification (DCA) Guide for 2023

One of the ways to stand out as a DevOps engineer is to gain certifications that attest to your expertise with DevOps tools. One of the most recognized and sought-after certifications is Docker Certified Associate (DCA).

This article analyzes the DCA exam curriculum and resources that can help you crack the certification test.

Why Get a Docker Certification?

Getting a Docker certification is a great way to demonstrate your knowledge and expertise in containerization. With Docker's increasing popularity, having a certification can set you apart from other candidates in the job market and open up new opportunities for career growth. Additionally, Docker certifications provide a strong foundation for learning related technologies and can help you become a more valuable asset to any organization.

Docker Certification Curriculum

The DCA Certification - awarded by Docker (proctored by Examity) - helps highlight your familiarity and expertise with application deployment using Docker. To pass the exam, you need to know container orchestration, service creation, and Docker Swarm.

Below are a few of the key concepts - and their weightage - that you should get hands-on experience with while preparing for a DCA certification:

Container Orchestration

This part essentially covers the basics of Docker and container orchestration; it carries about 25% of the total mark of your DCA exam. Additionally, you are also required to learn various container orchestration tools.

Below is a breakdown of the container orchestration part:

Setting up a swarm mode clusters
Locking a swarm cluster
Deploying applications into stack files
Running a service vs. Running a container
Manage a stack of running services
Replication of services
Replicated and global services
Troubleshoot a non-deploying service
Communication in Docker applications and legacy systems
Service templates.

Ensures you learn the basics of container orchestration, including containerized application deployment, managing release updates, and configuring failed containers. On successful completion of this part, it is expected that you’ll be able to create your first orchestrated, containerized application.

Docker Swarm and Kubernetes

Both Kubernetes and Docker Swarm are popular choices for container orchestration. Kubernetes focuses on open-source and modular orchestration, offering an efficient container orchestration solution for high-demand applications with complex configurations. On the other hand, Docker Swarm emphasizes ease of use, making it most suitable for simple applications that are quick to deploy and easy to manage. As you prepare for the DCA exam, you are required to have a working knowledge of both of these tools.

Try the Docker Compose Labs for free

Image Creation, Registry, and Management

This part carries about 20% of your overall mark in a DCA test. All Docker containers are based on images (static files containing everything needed to run an application). They are like a snapshot of a container that, when executed, creates a Docker container.

Below is a breakdown of this part:

Dockerfile options
Creating images using Dockerfile
Image management using CLI commands
Docker image layers
Deploying, configuring, and logging into the registry
Pushing, signing, and pulling images from the registry
Image deletion
Tagging images

Installation and Configuration

This is considered the most crucial part of the entire DCA learning. Though installation and configuration account for 15% of your total score, it should be noted that in the real world, a thorough knowledge of these concepts comes in handy almost regularly.

Content covered in installation and configuration includes:

Upgrading the Docker engine
Installing the Docker engine on various platforms
Logging drivers
User and team creation, user management
Sizing requirements
Client-server authentication for image registry access

This part familiarizes you with the Docker Universal Control Plane (UCP), Docker Daemon, and the Docker Trusted Registry (DTR).

Security & Networking

Networking and Security each carry 15% of the total score weightage. Networking in Docker involves connecting containers using Network Drivers. To fully grasp networking for the DCA exam, you’ll have to understand concepts such as:

Building Docker Bridge Networks for developer use
Troubleshooting logs
Publishing application ports
Identifying container ports and IP addresses
Describing the various types of network drivers
Configuring the Docker engine to use an external DNS
Performing HTTP and HTTPS load-balancing
Types of traffic on Docker Networks
Deploying services on Docker Networks

The DCA security chapter explores all authentication, encryption, and transport layer security content. This chapter will include:

Ensuring images pass security scans
The process of signing images
Docker Content Trust
Docker engine security
Swarm security
Distinguishing UCP workers from managers
Mutual Transport Layer Security (MTLS)
Using external certificates with the Docker universal control plane

Storage and Volumes

This chapter carries about 10% of your total exam score. Volumes offer a way to store information in Docker. For the DCA Associate exam, it is expected that you develop an understanding of the following:

How to quickly create volumes
The differences between volumes and bind mounts
Volume drivers and their most suitable use cases
Use of the device mapper
Object storage vs. block storage
Filesystem layers
Persistent storage in Docker
Cleanup of unused images
Storage in cluster nodes

Docker Enterprise Edition

The Docker Enterprise Edition (EE) is created for applications with mission-critical deployments. This gives you a managed solution with advanced container management, security scanning, and application logging & monitoring. This version can be deployed on all major Server operating systems, including Red Hat Enterprise Linux (RHEL), Ubuntu, Oracle Linux, Windows Server 2016, and SUSE Linux Enterprise Server (SLES). It is also available for major cloud providers, including Azure and AWS.

Exam Preparation

Certification Format Explanation

The Docker Certified Associate Exam takes one and a half hours and consists of 55 questions, including 44 Discrete Option Multiple-Choice (DOMC) and 11 Multiple-Choice (MCQ) questions. In DOMC, options are randomly shown so that the examinee can choose a YES or a NO. On the other hand, there are multiple correct answers for MCQ questions, all of which the examinee has to select.

Examity proctors this exam, and you can register by clicking this link. While there are no prerequisites, it is recommended that you have 6-12 months of experience with Docker to be fully prepared for the exam. The exam fee is $195, and there are no free retakes if you fail. You may, however, reschedule the exam before taking the test, so don’t feel pressured to take the exam unless you are completely ready.

Docker Certified Associate (DCA) Study Plan

As you prepare to study for your DCA exam, it is best to plan well to ensure that you do not miss any important topics and that you do not get overwhelmed with the amount of knowledge flowing in.

To plan well, you may divide the entire study into three parts –

The first is a lab setup that you can use for practice demos. This could either be a local Docker Command Line Interface (CLI), an on-cloud platform like AWS (if you have a subscription), or an Online Playground that emulates the Docker CLI.
The second consideration as part of your plan should include a set of practice exams that let you acquaint yourself with Discrete Option Multiple Choice (DOMC) and Multiple Choice Question (MCQ) exam formats used in the exam. To help with this, KodeKloud provides research questions, practice tests, and mock exams in both MCQ and DOMC format to familiarize you with the certification exam.
Look for helpful resources for meaningful research. Through KodeKloud’s practice lesson lectures, you can understand the DCA curriculum in a structured manner. Such lectures also act as great resources for understanding Docker commands and options, which come in handy during the exam. Ensure that your approach to learning is more practical than theoretical and that it helps solve real-world problems.

As the ultimate focus, your plan should be to gather knowledge that helps you gain a working knowledge of Docker in real world scenarios.

Study Schedule

Section	Total Learning Time (Hours)	Days (@ 2 Hrs/Day)	Days (@ 4 Hrs/Day)	Days (@ 6 Hrs/Day)
Docker Architecture	20	10	5	3
Images	20	10	5	3
Security	8	4	2	1
Networking	14	7	3.5	2
Storage	8	4	2	1
Docker Compose	12	6	3	2
Docker Swarm	26	13	6.5	4
Kubernetes	32	16	8	5
Docker Engine Enterprise	12	6	3	2
Docker Trusted Registry	6	3	1.5	1
Disaster Recovery	8	4	2	1
Mock Exams	28	14	7	5
Total	194	3 Months	1.5 Months	1 Month

The Study Schedule above indicates various subject areas you’ll need to cover, categorized into sections with estimated study times based on studying speeds.

The topics – Docker Architecture, Docker Swarm, Kubernetes, and Images, carry the bulk of the work, each taking over 20 hours to study. While topics on Security, Networking, and Disaster Recovery require roughly 8 hours for certification-level expertise. As part of the Study Schedule, you also need to take several mock exams covering each subject, requiring up to 28 hours of your time.

In total, to gain expert-level knowledge to help clear the DCA certification, we estimate that you’ll need to practice for three months if you’re learning for two hours a day, 1.5 months studying four hours a day, and one month studying 6 hours a day.

Sample Questions

Here is a quick quiz to help you assess your knowledge. Leave your answers in the comments below and tag us back.

Quick Tip – The questions below include a mix of DOMC and MCQ types.

Which statement best describes Quorum?

[A] Quorum is the minimum number of nodes that must be available for the cluster to function properly

[B] In the case of 3 manager nodes, the quorum is 3

[C] One of the best practices: maintain an odd number of managers in the swarm to support manager node failures

2. Which of the following is a recommended best practice while taking backups of a swarm cluster?

[A] Perform the backup operations from a swarm manager node that is a leader

[B] Perform the backup operations from a swarm worker node

[C] Perform the backup operations from a swarm manager node that is not a leader

3. Which of the following steps are required to add a worker node in the UCP cluster?

[A] Provision a node and Install the Docker enterprise engine on it

[B] Run the docker swarm join command to join the new node to the cluster

[C] Deploy an instance of the ucp-agent on the new node

[D] ucp-agent then installs the necessary components on the worker node

4. What will happen if the container consumes more memory than its limit?

[A] The container will not be killed

[B] the container will be killed with an Out of Memory exception

[C] the container’s memory usage will be throttled

5. How does docker map a port on a container to a port on the host?

[A] Using an internal load balancer

[B] FirewallD Rules

[C] Using an external load balancer

[D] IPTables Rules

6. Which of the following solutions supports network policies?

[A] kube-router

[B] Calico

[C] Flannel

[D] Weave-Net

7. Which command can be used to stop (only and not delete) the whole stack of containers created by the compose file?

[A] docker-compose down

[B] docker-compose stop

[C] docker-compose destroy

[D] docker-compose halt

8. What is the command to run 3 instances of httpd on a swarm cluster?

[A] docker swarm service create --instances=3 httpd

[B] docker swarm service create --replicas=3 httpd

[C] docker service create --instances=3 httpd

[D] docker service create --replicas=3 httpd

9. In which service does the DTR image scanning occur?

[A] A service known as the dtr-jobrunner container

[B] A service known as the dtr-registry container

[C] A service known as the dtr-api container

[D] A service known as the dtr-runner container

10. Assume that you have 3 managers in your cluster; what will happen if 2 managers fail at the same time? Select all the right answers.

[A] The services hosted on the available worker nodes will continue to run

[B] The services hosted on the available worker nodes will stop running

[C] New services/workers can be created or added

[D] New services/workers can’t be created or added

Study Resource

Enroll in our Docker Certified Associate Exam Course.

Mumshad Mannambeth

Oct 2, 2022 • 8 min read