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 start

Answer

docker swarm create

Answer

docker cluster init

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

Managers handle networking; workers handle storage

Answer

Managers run only one container; workers run many

Answer

There is no functional difference

Question 3

Which command creates a new service in a Docker Swarm?

Accepted Answer

docker service create

Answer

docker run --swarm

Answer

docker deploy service

Answer

docker swarm service add

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

Sets the number of manager nodes

Answer

Defines how many volumes to create

Answer

Controls how many networks the service joins

Question 5

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

Accepted Answer

Both A and B are correct

Answer

docker service scale my-service=5

Answer

docker service update --replicas 5 my-service

Answer

docker swarm scale my-service 5

Question 6

What is an overlay network in Docker Swarm?

Accepted Answer

A distributed network that spans multiple Docker hosts in a swarm

Answer

A network that only exists on a single host

Answer

A network used exclusively for management traffic

Answer

A read-only network for container inspection

Question 7

What does the docker stack deploy command do?

Accepted Answer

Deploys a multi-service application defined in a Compose file to a swarm

Answer

Builds Docker images from source code

Answer

Pushes images to a registry

Answer

Updates a single service

Question 8

Which consensus algorithm does Docker Swarm use to maintain cluster state?

Accepted Answer

Raft

Answer

Paxos

Answer

Zab

Answer

PBFT

Question 9

What is a Docker Swarm task?

Accepted Answer

A single container instance running as part of a service

Answer

A scheduled cron job

Answer

A background health check

Answer

A Dockerfile build step

Question 10

How do you retrieve the join token for worker nodes in a Docker Swarm?

Accepted Answer

docker swarm join-token worker

Answer

docker swarm get-token worker

Answer

docker swarm token --worker

Answer

docker swarm info --token