DCA Data Analysis & Reporting 5

Question 1

Which log driver is the default for Docker containers when no driver is explicitly configured?

Accepted Answer

json-file

Answer

By default, Docker uses the `json-file` log driver, storing logs as JSON on the host filesystem.

Question 2

You want `docker logs` to follow output in real time, similar to `tail -f`. Which flag do you use?

Accepted Answer

--follow

Answer

`docker logs --follow` (or `-f`) continuously streams new log output as the container produces it.

Question 3

A Swarm service is running 5 replicas. Which command retrieves aggregated logs from all replicas?

Accepted Answer

docker service logs <service_name>

Answer

`docker service logs` aggregates log output from all replicas of a Swarm service.

Question 4

When the `json-file` log driver is configured with `max-size=10m` and `max-file=3`, what happens when logs exceed 10MB?

Accepted Answer

The log file rotates and old files are deleted when count exceeds 3

Answer

Docker rotates the log file at `max-size` and keeps only `max-file` rotated files, deleting the oldest.

Question 5

Which command would report the total number of images, containers, and volumes on a Docker host?

Accepted Answer

docker info

Answer

`docker info` provides a comprehensive summary including counts of images, containers, and volumes.

DCA - Docker Certified Associate Exam Practice Test