ESXi 5.x provides many options for PXE booting the installer and using an installation or upgrade script.
For information about setting up a PXE infrastructure, see PXE Booting the ESXi Installer.
For information about creating and locating an installation script, see About Installation and Upgrade Scripts.
For specific procedures to PXE boot the ESXi installer and use an installation script, see one of the following topics:
For information about using Auto Deploy to perform a scripted upgrade by PXE booting, see Using vSphere Auto Deploy to Reprovision Hosts.