To auto-deploy an ESXi server, we need to have the ESXi offline bundle ready. The vanilla version of the offline bundle can be downloaded from VMware's website. Customized offline bundles from the server vendors are available for download from the vendor's website. They are also available at VMware's download page, under the Drivers & Tools tab and listed under the category OEM Customized Installer CDs.
You can download the ESXi 5.5 offline bundle from the VMware downloads page, under the VMware vSphere product category. Perform the following steps: