vCenter Server runs on a Photon OS™ guest operating system.
vCenter Server is a collection of services designed for managing and monitoring vSphere installations. vCenter Server responds to CLI commands, requests from the vSphere Client, and API requests from custom clients. API clients can be written in a choice of several software languages.
vCenter Server is managed by CLI, Web interfaces, or API requests. These requests help you manage vCenter Server configuration, monitor resource usage, or back up and restore the vCenter Server instance. You can also use API requests to check the health of vCenter Server. This programming guide explains how to use the vSphere Automation APIs that are available to manage and monitor vCenter Server.
For more information about the capabilities of vCenter Server, see vCenter Server Configuration.