DCA Docker Swarm & Orchestration 3

Question 1

What is the name of the default overlay network created automatically when a Docker Swarm is initialized?

Accepted Answer

ingress

Answer

Docker Swarm creates the `ingress` overlay network during `docker swarm init` to support the routing mesh for published service ports.

Question 2

What does the Docker Swarm routing mesh (ingress network) enable?

Accepted Answer

Any Swarm node to accept connections on a published port and route them to an active task, regardless of where that task runs

Answer

The routing mesh allows every Swarm node to receive external connections on a published service port and forward them to a running task, even if no task is scheduled on that particular node.

Question 3

Which command updates the image of a running service named 'api' to use the tag '2.0'?

Accepted Answer

docker service update --image api:2.0 api

Answer

`docker service update --image api:2.0 api` triggers a rolling update of the service's tasks to use the new image.

Question 4

What does the `--update-failure-action rollback` flag do when used with `docker service update`?

Accepted Answer

Automatically reverts the service to its previous configuration when the update encounters task failures

Answer

`--update-failure-action rollback` instructs Swarm to automatically restore the service to the last known-good configuration if tasks fail during the update.

Question 5

How are Docker secrets stored and accessed in Swarm mode?

Accepted Answer

Encrypted in the Raft log at rest, transmitted over mutual TLS, and mounted as files under /run/secrets/ inside authorized containers

Answer

Secrets are encrypted at rest in the Swarm's Raft store, sent to worker nodes only over TLS, and exposed to containers as in-memory files at `/run/secrets/<secret_name>`.

DCA - Docker Certified Associate Exam Practice Test

DCA - Docker Certified Associate Exam Practice Test

DCA Docker Swarm & Orchestration 3