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_gwbridge

Answer

host

Answer

swarm_default

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

DNS-based service discovery between containers

Answer

A dedicated hardware load balancer on manager nodes

Answer

Encrypted container-to-container communication within a service

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 upgrade api --image api:2.0

Answer

docker service redeploy --tag 2.0 api

Answer

docker update service api:2.0

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

Prevents the update from starting if any existing task is unhealthy

Answer

Stops the rolling update and waits for manual operator intervention

Answer

Retries failed tasks indefinitely until they succeed

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

As plain-text environment variables injected into containers at runtime

Answer

As base64-encoded values embedded in docker-compose.yml files

Answer

As encrypted environment variables passed through the Docker daemon socket

Question 6

Which command rolls back a service named 'db' to its previous deployed configuration?

Accepted Answer

docker service rollback db

Answer

docker service undo db

Answer

docker service revert db

Answer

docker service update --previous db

Question 7

What is the maximum number of manager nodes Docker officially recommends for a production Swarm cluster?

Accepted Answer

7

Answer

3

Answer

5

Answer

11