You use the Orchestrator client to run and create workflows and access the plug-in API. You can use either the embedded vCenter Orchestrator instance in your vCloud Automation Center installation, or an external vCenter Orchestrator server.
vCenter Orchestrator powers the vCloud Automation Center plug-in. Orchestrator is a development and process-automation platform that provides a library of extensible workflows to manage the vCenter infrastructure and other technologies.
Orchestrator allows integration with management and administration solutions through its open plug-in architecture.