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Mirantis Docker Certified Associate (DCA)

Practice Questions298 questions

Exam Review

Key Facts: DCA Exam

~55

Exam Questions

Mirantis

~65%

Passing Score

Approximate; Mirantis does not publish exact cut score

90 min

Exam Duration

Mirantis

$195

Exam Fee

Mirantis

Online

Delivery

Mirantis proctored

2 years

Validity

Recertification required

The DCA exam has approximately 55 multiple-choice scenario questions in 90 minutes, delivered online by Mirantis. Topic areas: Docker images and containers (~20%), Docker networking (~20%), Docker Swarm orchestration (~20%), storage and volumes (~15%), security (~15%), and image registries and troubleshooting (~10%). Exam fee is $195 USD. The certification is valid for two years.

Sample DCA Practice Questions

Try these sample questions to review concepts for the DCA exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Which Dockerfile instruction sets the base image for a build?

A.FROM

B.BASE

C.IMAGE

D.START

Explanation: FROM must be the first instruction in a Dockerfile (apart from ARG) and declares the base image from which the new image is built.

2What is the difference between the COPY and ADD instructions in a Dockerfile?

A.ADD supports URL sources and automatic tar extraction; COPY only copies local files and directories

B.COPY supports URL sources; ADD only copies local files

C.ADD is faster than COPY

D.COPY creates a new layer; ADD does not

Explanation: COPY is the preferred instruction for simple local file copying. ADD additionally supports fetching from URLs and automatically unpacking tar archives, but this extra behavior can be surprising.

3What is the purpose of the RUN instruction in a Dockerfile?

A.Executes a command in a new layer on top of the current image and commits the result

B.Sets the default command to run when a container starts

C.Defines environment variables

D.Exposes a port

Explanation: RUN executes commands (e.g., apt-get install, pip install) during the image build process and commits the resulting file system changes as a new layer.

4What is the difference between CMD and ENTRYPOINT in a Dockerfile?

A.ENTRYPOINT defines the fixed executable; CMD provides default arguments that can be overridden at runtime

B.CMD defines the fixed executable; ENTRYPOINT provides overridable defaults

C.They are interchangeable

D.ENTRYPOINT is only used in multi-stage builds

Explanation: ENTRYPOINT sets the main process (not easily overridden at runtime without --entrypoint flag). CMD provides default arguments to ENTRYPOINT or a default command, easily overridden by passing arguments to 'docker run'.

5What does the EXPOSE instruction in a Dockerfile do?

A.Documents which port the container listens on at runtime but does NOT publish it to the host

B.Publishes the port to the host automatically

C.Opens the port in the host firewall

D.Maps the container port to a random host port

Explanation: EXPOSE is documentation only. It informs Docker and developers which port the container expects to use. Actual port publishing requires -p or -P flags with 'docker run'.

6What command builds a Docker image from a Dockerfile in the current directory and tags it as 'myapp:1.0'?

A.docker build -t myapp:1.0 .

B.docker create -t myapp:1.0 .

C.docker image build --name myapp:1.0

D.docker make myapp:1.0

Explanation: 'docker build -t myapp:1.0 .' builds an image using the Dockerfile in the current directory (.) and tags it with the name myapp and tag 1.0.

7What is a multi-stage Dockerfile build and what is its primary benefit?

A.Using multiple FROM instructions in one Dockerfile to separate build and runtime stages, producing a smaller final image

B.Building the same image for multiple platforms simultaneously

C.Running multiple Dockerfiles in sequence

D.A way to cache build layers across multiple builders

Explanation: Multi-stage builds use multiple FROM instructions. Build tools and source code stay in intermediate stages; only the compiled artifacts are copied into the final minimal stage, dramatically reducing image size.

8Which Docker command removes all stopped containers, unused networks, dangling images, and build cache?

A.docker system prune

B.docker clean all

C.docker rm --all

D.docker purge

Explanation: 'docker system prune' reclaims disk space by removing all stopped containers, networks not used by any container, dangling images, and build cache. Adding -a also removes unused images.

9What is the default network driver used when you create a container without specifying a network?

A.bridge

B.host

C.overlay

D.none

Explanation: By default, containers connect to the 'bridge' network (docker0 on Linux). Each container gets a private IP on the bridge and can communicate with others on the same bridge.

10What is the key difference between the 'host' network driver and the 'bridge' network driver?

A.Host network shares the host's network namespace directly (no isolation); bridge creates a virtual network with NAT isolation

B.Host network is for overlay; bridge is for single-host

C.Host network requires extra plugins; bridge is built-in

D.Host network is faster because it skips the Docker daemon

Explanation: With 'host' networking, the container uses the host's IP and ports directly without NAT. With 'bridge', containers get their own virtual network with NAT between container and host.

About the DCA Exam

The Docker Certified Associate (DCA) exam validates practical container skills across the Docker platform. It tests Dockerfile authoring and image lifecycle, Docker networking (bridge, host, overlay), storage (volumes, bind mounts, tmpfs), Swarm orchestration (services, stacks, rolling updates), security (Docker Content Trust, capabilities, seccomp), and image registry operations.

Exam sponsor: Mirantis (online proctored). The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Questions

55 questions

Time Limit

90 minutes

Passing Score

65% (approximate)

Exam / Certification Fees

$195

Exam sponsor website

Reported exam pass rate: ~65%. for well-prepared candidates (industry estimate) This describes exam candidates, not OpenExamPrep users or results from using our resources. Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Official sources

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

20%

Docker Image and Container Lifecycle

Dockerfile instructions (FROM, RUN, COPY, ADD, CMD, ENTRYPOINT, EXPOSE, ENV, ARG, VOLUME, WORKDIR), image layers and caching, multi-stage builds, container lifecycle (create/start/stop/rm), docker build flags

20%

Docker Networking

Bridge, host, overlay, macvlan, and none network drivers; user-defined bridge networks; port publishing (-p / --publish); DNS resolution in user-defined networks; container-to-container communication; Swarm overlay scope; network inspection

20%

Docker Swarm Orchestration

docker swarm init/join, manager and worker roles, service create/update/scale/rollback, replicated vs global services, rolling updates (--update-delay, --update-parallelism), stack deploy with Compose v3+, Swarm secrets and configs

15%

Storage and Volumes

Named volumes, bind mounts, tmpfs mounts; differences and use cases; volume drivers; volume lifecycle (create/inspect/prune); --mount vs -v flag syntax; volume sharing between containers

15%

Docker Security

Docker Content Trust (DCT) and image signing with Notary; Linux capabilities and --cap-add/--cap-drop; seccomp security profiles; AppArmor profiles; user namespaces; read-only containers; secret management; TLS certificates for daemon

10%

Image Registries and Troubleshooting

Docker Hub, private registries, docker login/push/pull/tag, digest pinning, registry authentication; docker inspect, docker logs, docker stats, docker events, docker system df, container troubleshooting patterns

Preparing for the DCA Exam

What You Need to Know

Passing score: 65% (approximate)
Exam length: 55 questions
Time limit: 90 minutes
Exam / certification fees: $195 Official sources

Using Our Practice Resources

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DCA: Suggested Study Strategy

1Know every Dockerfile instruction and its effect on layers: RUN creates a layer, COPY/ADD copies files, CMD/ENTRYPOINT set defaults — and know the difference between CMD and ENTRYPOINT

2Master the network driver decision: bridge (default, single host), host (no network isolation), overlay (multi-host Swarm), macvlan (physical network MAC addresses), none (no networking)

3Understand volume vs bind mount vs tmpfs: volumes are managed by Docker and persist; bind mounts reference host paths; tmpfs is in-memory only

4Practice the full Swarm lifecycle: swarm init → service create → service scale → service update → rollback — know the --update-delay and --update-parallelism flags

5Know Docker Content Trust: set DOCKER_CONTENT_TRUST=1 to enforce signed images; understand that unsigned images are rejected when DCT is enabled

6Study --mount vs -v syntax: --mount is explicit and preferred; -v is legacy shorthand — both appear on exam questions

7Practice docker inspect output: know how to extract IP addresses, mounts, network settings, and image layers from JSON output

Frequently Asked Questions

What is the Docker Certified Associate exam?

The DCA (Docker Certified Associate) is a vendor certification now offered by Mirantis (which acquired Docker Enterprise) that validates practical Docker skills. It tests Dockerfile authoring, container networking, storage, Swarm orchestration, security, and registry operations. Targeted at engineers with hands-on container experience.

How many questions are on the DCA exam?

The DCA has approximately 55 multiple-choice scenario-based questions and a 90-minute time limit, delivered online by Mirantis. Many questions present a Docker command or scenario and ask which option or configuration achieves the desired outcome.

How much does the DCA exam cost?

The DCA exam costs $195 USD. The fee covers a single attempt; retakes require an additional fee.

What are the largest topic areas on the DCA exam?

Docker images/containers, networking, and Swarm orchestration are each weighted at roughly 20%. Storage and volumes (~15%) and security (~15%) follow. Image registries and troubleshooting (~10%) rounds out the exam.

Does the DCA certification expire?

Yes — the Docker Certified Associate credential is valid for two years. To maintain certification, retake and pass the current exam version before expiration.

How should I prepare for the DCA exam?

Plan for 40-60 hours of study over 6-8 weeks. Install Docker locally; write multi-stage Dockerfiles; set up Swarm with managers and workers; practice service creation, updates, and rollbacks; configure networking with multiple drivers; and manage volumes. Take 100+ practice questions targeting 80%+ before scheduling.

What jobs benefit from DCA certification?

DCA aligns with roles such as DevOps Engineer, Platform Engineer, Site Reliability Engineer, Container Engineer, and Infrastructure Engineer. It is commonly cited in job postings for organizations using Docker in development and production environments.