With the vSphere Auto Deploy ESXi Installation, you can provision and reprovision large numbers of ESXi hosts efficiently with vCenter Server.

Using the Auto Deploy feature, vCenter Server loads the ESXi image directly into the host memory. Auto Deploy does not store the ESXi state on the host disk. vCenter Server stores and manages ESXi updates and patching through an image profile, and, optionally, the host configuration through a host profile. You can create image profiles with ESXi Image Builder CLI, and host profiles using the vSphere Client. See Using vSphere ESXi Image Builder CLI and vSphere Host ProfilesvSphere Host Profiles.

The first time you install a host with Auto Deploy, the host PXE boots and establishes contact with the Auto Deploy server, which streams the image profile and any host profile to the host. The host starts, using the image profile, and Auto Deploy assigns the host to the appropriate vCenter Server system.

When you restart the host, vCenter Server uses the Auto Deploy feature to provision the host with the appropriate image and host profile. If the image profile changes, for example, for an update or patch, the administrator can propagate the change to all hosts that are provisioned with Auto Deploy and managed by a vCenter Server system. This ability makes Auto Deploy an efficient way to provision and reprovision large numbers of hosts, and to enforce compliance to a master ESXi image.

See Understanding vSphere Auto Deploy.