Docker Certified Associate study guide
DCA · Work through your exam, one topic at a time.
The Docker Certified Associate (DCA) is a vendor certification aimed at practitioners who build, ship, and run containerized applications using Docker tooling. Candidates typically come from DevOps, platform, and application-development roles, and are expected to be comfortable with the Docker CLI, image workflows, and multi-container deployments rather than with a single product feature. The published blueprint is organized around six areas: orchestration; image creation, management, and registry; installation and configuration; networking; security; and storage and volumes. Exact domain weightings could not be confirmed from the vendor page at the time of retrieval, so treat any percentage you see quoted elsewhere as unconfirmed. The DCA study guide has 6 sections and about 1,816 words.
01Orchestration
Swarm mode turns a set of Docker hosts into a cluster of managers (Raft consensus) and workers . Objects nest: a service declares desired state, the orchestrator creates tasks , and each task runs exactly one container .
311 words, about 2 min02Image Creation, Management, and Registry
Every Dockerfile instruction that changes the filesystem makes a layer; RUN , COPY , and ADD are the big three. Order them least-volatile to most-volatile so the build cache survives: base OS packages, then dependency manifests, then source code.
305 words, about 2 min03Installation and Configuration
Docker is a CLI client ( docker ) talking to a daemon ( dockerd ). The daemon reads /etc/docker/daemon.json at startup.
288 words, about 1 min04Networking
Bridge is the default. A user-defined bridge network gives containers embedded DNS, so they reach each other by container name or network alias.
296 words, about 1 min05Security
Containers share the host kernel. Isolation comes from namespaces, resource limits from cgroups, and filtering from capabilities, seccomp, and AppArmor/SELinux.
305 words, about 2 min06Storage and Volumes
An image is read-only layers; a container adds a thin writable layer managed by the storage driver (overlay2). That layer is deleted with the container, so anything you must keep belongs on a volume or bind mount.
311 words, about 2 min