You can install, upgrade, or migrate ESXi from a CD/DVD drive using a script that specifies the installation or upgrade options.

You can start the installation or upgrade script by entering a boot option when you start the host. You can also create an installer ISO image that includes the installation script. With an installer ISO image, you can perform a scripted, unattended installation when you boot the resulting installer ISO image. See Create an Installer ISO Image with a Custom Installation or Upgrade Script.

Before you run the scripted installation, upgrade, or migration, verify that the following prerequisites are met:

The system on which you are installing, upgrading, or migrating meets the hardware requirements. See ESXi Hardware Requirements.

You have the ESXi installer ISO on an installation CD/DVD. See Download and Burn the ESXi Installer ISO Image to a CD or DVD.

The default installation or upgrade script (ks.cfg) or a custom installation or upgrade script is accessible to the system. See About Installation and Upgrade Scripts.

You have selected a boot command to run the scripted installation, upgrade or migration. See Enter Boot Options to Start an Installation or Upgrade Script. For a complete list of boot commands, see Boot Options.


Boot the ESXi installer from the CD or DVD using the local CD/DVD-ROM drive.


When the ESXi installer window appears, press Shift+O to edit boot options.

ESXi Installer screen


Type a boot option that calls the default installation or upgrade script or an installation or upgrade script file that you created.

The boot option has the form ks=.


Press Enter.

The installation, upgrade, or migration runs, using the options that you specified.