Docker Containerization Docker Swarm and Orchestration

Question 1

What command initializes a Docker Swarm on the current node?

Accepted Answer

docker swarm init

Answer

docker swarm init initializes the current Docker Engine as a swarm manager node.

Question 2

In Docker Swarm, what is the difference between a manager node and a worker node?

Accepted Answer

Managers orchestrate services and maintain cluster state; workers only execute tasks

Answer

Manager nodes maintain the swarm state using the Raft consensus algorithm and schedule tasks, while worker nodes only execute the assigned containers.

Question 3

Which command creates a new service in a Docker Swarm?

Accepted Answer

docker service create

Answer

docker service create is used to create and deploy a new service within a Docker Swarm cluster.

Question 4

What is the purpose of the --replicas flag when creating a Docker Swarm service?

Accepted Answer

Specifies how many task instances of the service should run

Answer

The --replicas flag sets the desired number of running task instances (containers) for the service across the swarm.

Question 5

How do you scale an existing Docker Swarm service to 5 replicas?

Accepted Answer

Both A and B are correct

Answer

Both 'docker service scale my-service=5' and 'docker service update --replicas 5 my-service' achieve the same result of scaling the service to 5 replicas.

Docker Practice Test

Docker Practice Test

Docker Containerization Docker Swarm and Orchestration