Docker Containerization Docker Swarm and Orchestration 4

Question 1

What command displays the live log output from all tasks of a Swarm service?

Accepted Answer

docker service logs <service>

Answer

The 'docker service logs' command aggregates and streams log output from all running tasks of the specified service.

Question 2

Which flag limits the CPU resources available to each task in a Swarm service?

Accepted Answer

--limit-cpu

Answer

The --limit-cpu flag sets a hard CPU limit (in fractions of a core) that each task in the service is not allowed to exceed.

Question 3

In Docker Swarm, what is the role of the 'ingress' network?

Accepted Answer

It implements the routing mesh that distributes external traffic to service tasks

Answer

The ingress overlay network powers the Swarm routing mesh, allowing any node to accept traffic on a published port and route it to an available task.

Question 4

What happens when you run 'docker stack deploy' with an updated compose file?

Accepted Answer

It performs a rolling update on changed services and leaves unchanged services running

Answer

Re-running 'docker stack deploy' with an updated file applies changes incrementally — it updates modified services via rolling updates without restarting unchanged ones.

Question 5

Which Swarm service constraint targets only nodes that are Swarm manager nodes?

Accepted Answer

--constraint 'node.role==manager'

Answer

The built-in 'node.role' constraint can be set to 'manager' or 'worker' to restrict where a service's tasks are scheduled.

Docker Practice Test

Docker Practice Test

Docker Containerization Docker Swarm and Orchestration 4