DCA Technology & Digital Tools 4

Question 1

Which command exports a Docker container's filesystem as a tar archive (not an image)?

Accepted Answer

docker export

Answer

`docker export` streams the container's filesystem as a flat tar; unlike `docker save`, it does not preserve image layers or metadata.

Question 2

What networking mode allows a container to share the host machine's network stack directly?

Accepted Answer

host

Answer

In `host` network mode, the container bypasses network namespacing and uses the host's interfaces and ports directly.

Question 3

In Docker Compose, which key under a service definition maps to `docker run --restart`?

Accepted Answer

restart

Answer

The `restart` key in a Compose service definition (e.g., `restart: always`) maps directly to Docker's restart policy.

Question 4

Which Docker object stores sensitive data like passwords and TLS certificates, injecting them into containers without embedding in images?

Accepted Answer

Secret

Answer

Docker Secrets are encrypted at rest in the Swarm Raft log and mounted into authorized containers as in-memory tmpfs files.

Question 5

What is the effect of running `docker system prune -a`?

Accepted Answer

Removes all unused containers, networks, images (including tagged), and build cache

Answer

`docker system prune -a` reclaims space by removing all unused resources including tagged images not referenced by any container.

DCA - Docker Certified Associate Exam Practice Test