DCA Technology & Digital Tools 5

Question 1

Which `docker inspect` format filter extracts only the container's IP address from the default bridge network?

Accepted Answer

--format '{{.NetworkSettings.IPAddress}}'

Answer

`{{.NetworkSettings.IPAddress}}` is the correct Go template path to extract the container IP from bridge network settings.

Question 2

What does the `HEALTHCHECK` instruction in a Dockerfile do?

Accepted Answer

Defines a command Docker periodically runs to assess if the container is healthy

Answer

`HEALTHCHECK` tells Docker how to test a container's health; a failing check marks the container as `unhealthy` in `docker ps`.

Question 3

In Docker Swarm, which placement constraint syntax pins service tasks to nodes labeled `env=production`?

Accepted Answer

--constraint 'node.labels.env == production'

Answer

The correct syntax references `node.labels.<key>` in a constraint expression to target nodes by their custom labels.

Question 4

Which log driver sends Docker container logs directly to a syslog endpoint?

Accepted Answer

syslog

Answer

The `syslog` log driver forwards container logs to a syslog server using RFC 5424 format over UDP, TCP, or TLS.

Question 5

What is the role of the Notary service in Docker Trusted Registry?

Accepted Answer

Provides cryptographic signing and verification of image content

Answer

Notary implements The Update Framework (TUF) to sign image manifests, enabling Docker Content Trust verification.

DCA - Docker Certified Associate Exam Practice Test