You can manage virtual machines directly through the ESX/ESXi host or through a vCenter Server system.

If you manage your virtual machines directly through an ESX/ESXi host (a single or standalone system), you can manage only those virtual machines and their resources installed on that host.

If you manage your virtual machines through a vCenter Server system, you can manage multiple virtual machines and their resources distributed over many ESX/ESXi hosts. Multiple vCenter Server systems can be joined together in a vCenter Server Connected Group to allow them to be managed with a single vSphere Client connection.

The vSphere Client is a flexible, configurable interface for managing your virtual machines through an ESX/ESXi host or through vCenter Server.

vSphere Components with an ESX/ESXi Host illustrates the components in an ESX/ESXi Virtual Infrastructure.

vSphere Components with an ESX/ESXi Host
vSphere components with an ESX/ESXi host

vSphere Components with a vCenter Server System illustrates the components in a vCenter Server Virtual Infrastructure.

vSphere Components with a vCenter Server System
vSphere Components with a vCenter Server system