Docker Swarm Orchestration Concepts

1. In Docker Swarm, what is the default scheduling mode for services?

Spread (distribute across nodes)

Binpack (consolidate on fewer nodes)

Random (arbitrary placement)

Pinned (fixed node assignment)

2. What is the purpose of rolling updates in Docker Swarm?

Backup service configurations

Update tasks gradually while maintaining availability

Distribute load across all nodes

Encrypt service communication

3. How do you update a running service with a new image in Docker Swarm?

Docker service update --image newimage:tag myservice

Docker service restart myservice

Docker service recreate myservice

Docker swarm update myservice

4. Which port does Docker Swarm use for node communication by default?

2375

2376

2377

7946

5. What happens when a manager node loses quorum in a Swarm?

Services continue running; no new changes allowed

All tasks are immediately stopped

Worker nodes become managers automatically

The swarm is destroyed

6. Which Docker Swarm feature ensures a service always has the desired number of replicas?

Reconciliation

Replication

Desired state reconciliation

Auto-healing

7. In Docker Swarm, what is a stack?

A collection of related services defined in a Compose file

A backup of the cluster state

A group of worker nodes

A persistent storage volume

8. How do you join an existing Docker Swarm as a worker node?

Docker swarm init --token

Docker swarm join --token TOKEN MANAGER_IP:2377

Docker node join MANAGER_IP

Docker cluster add

9. What is the purpose of Docker Swarm's internal DNS?

Resolve external domain names

Enable service discovery within the swarm

Manage node IP addresses

Encrypt network traffic

10. Which command scales a service to a specific number of replicas?

Docker service scale myservice=5

Docker service update --replicas=5 myservice

Both A and B

Docker swarm scale myservice 5

11. What command initializes a Docker Swarm?

Docker swarm init

Docker swarm start

Docker swarm create

Docker cluster init

12. What does the --global flag do when creating a Docker Swarm service?

Deploys one task per node in the swarm

Makes the service accessible globally

Enables cross-swarm communication

Sets global resource limits

13. Which placement constraint restricts services to nodes with specific labels?

Node.hostname

Node.labels

Service.constraint

Engine.labels

14. How do you drain a node in Docker Swarm without losing running tasks?

Docker node drain

Docker node update --availability drain

Docker swarm leave --force

Docker service drain

15. What is the purpose of the Raft consensus algorithm in Docker Swarm?

Route traffic between containers

Maintain consistent cluster state across managers

Encrypt communication between nodes

Allocate CPU resources to tasks

16. Which Docker Swarm networking driver provides automatic load balancing?

Bridge

Host

Overlay

Macvlan

17. What is the primary difference between a service and a task in Docker Swarm?

Services are blueprints; tasks are running instances

Tasks are blueprints; services are running instances

Services only run on managers; tasks run on workers

There is no difference

18. Which command promotes a worker node to manager?

Docker node promote

Docker swarm promote

Docker node update --role manager

Docker promote worker

19. How many manager nodes are recommended in a production Swarm cluster?

Exactly 1

Odd number (1, 3, 5, 7)

Even number (2, 4, 6)

Minimum 5

20. In Docker Swarm, what is the primary role of a manager node?

Execute containerized workloads only

Maintain cluster state and orchestrate services

Monitor logs from worker nodes

Provide persistent storage for containers

Docker Associate Docker Swarm Orchestration Quiz