Orchestrator contains a workflow library and a workflow engine to allow you to create and run workflows that automate orchestration processes. You run workflows on the objects of different technologies that Orchestrator accesses through a series of plug-ins.

Orchestrator provides a standard set of plug-ins, including a plug-in for vCenter Server, to allow you to orchestrate tasks in the different environments that the plug-ins expose.

Orchestrator also presents an open architecture to allow you to plug in external third-party applications to the orchestration platform. You can run workflows on the objects of the plugged-in technologies that you define yourself. Orchestrator connects to a directory services server to manage user accounts, and to a database to store information from the workflows that it runs. You can access Orchestrator, the Orchestrator workflows, and the objects it exposes through the Orchestrator client interface, through a Web browser, or through Web services.

VMware vCenter Orchestrator Architecture
The VMware vCenter Orchestrator Architecture consists of a workflow engine and a client application. The graphical representation of the architecture includes some of the default Orchestrator plug-ins (vCenter Server, XML, SSH, SQL, SMTP) and database. It also includes the directory services or vCenter Single Sign On, which Orchestrator requires for managing user permissions. The database and Directory services or vCenter Single Sign On are connected to the workflow engine. A vCenter Server instance is connected to the platform through the vCenter Server plug-in.