Question

What's the command to scale the number of instances in your swarm cluster, once the service is already running/deployed?

a) docker service scale =
b) docker swarm scale =
c) docker deploy --scale =
d) docker stack scale =

Answer 1

The correct command to scale the number of instances in a Docker swarm cluster for a running service is 'docker service scale SERVICE=REPLICAS'. For example, to scale a service to four instances, you would use 'docker service scale webapp=4'.

Step-by-step explanation:

The command to scale the number of instances for a service in Docker swarm after it has already been deployed is docker service scale. This command allows you to adjust the number of replica tasks running for a service, which is particularly useful for accommodating changes in demand or workload. The syntax follows this pattern: docker service scale SERVICE=REPLICAS, where SERVICE is the name or ID of the service you intend to scale, and REPLICAS is the desired number of instances. For example, if you want to scale a service named 'webapp' to run 4 instances, you would use: docker service scale webapp=4.