Service brokers compliant with the Open Service Broker API specification allow platforms to provision a new instance of a service. And the service broker provides all the information that your application or container needs to connect to the service instance. Then, you simply connect to the service instance, regardless of how or where the service is running.
Provisioning a new service instance doesn’t necessarily mean that the service broker has to spin up a new virtual machine. For example, provisioning could also mean reserving some space in database which has previously been created. The specification purposefully provides a high-level abstraction, and is not opinionated on what should happen behind the API.