I was a beta test taker for the DCA Exam in the fall of 2017. At the time it was 100% Docker CLI and Engine features.
However, in 2022, it's not a sought-after certification and isn't even controlled by Docker Inc. anymore. I don't recommend you bother with the DCA unless you use the Mirantis Kubernetes cluster solution. The DCA is now as much about Kubernetes as it is about Docker CLI, and I think it's a much better use of your time to get more recognized industry certs. It'll serve your career to "fill in the gaps" if you don't already have a certification in the below areas (Assuming you're going for a DevOps or Cloud admin type job). In order of priority:
Linux
Linux Foundation: LFCE, LFCS, LFCA, etc.
CompTIA Linux+
Cloud (of your choice, ideally the one your company or ideal job is using)
DevOps fundamentals
DevOps Institute (many cert options)
AWS specific: AWS Certified DevOps Engineer
Azure specific: Microsoft Certified: DevOps Engineer Expert (multiple certs)
GCP specific: Professional Cloud DevOps Engineer
Kubernetes
KCNA: Kubernetes and Cloud Native Associate (beginner in Cloud Native tools like K8s)
CKA: Certified Kubernetes Administrator (cluster admin)
CKAD: Certified Kubernetes Application Developer (dev building apps on top of Kubernetes)
From there you can get more specific into the security, development, or operations expertise and certs.
Note that the Linux Foundation also has an excellent visual roadmap for certification.
Background info on the DCA if you're still interested:
Back in 2019, Mirantis bought a majority of Dockers employees and enterprise software, including "Docker Enterprise". They updated the DCA test and it now includes Kubernetes basics like pods, services, and manifests in addition to the docker CLI. Be careful of other guides you see (including DCA courses here on Udemy) because they may be outdated as of 2021, when it was last updated (as far as I know). The updated study guide can be found here: