You can customize the standard ESXi installer ISO image with your own installation or upgrade script. This customization enables you to perform a scripted, unattended installation or upgrade when you boot the resulting installer ISO image.

Linux machine

The ESXi ISO image VMware-VMvisor-Installer-6.x.x-XXXXXX.x86_64.iso,where 6.x.x is the version of ESXi you are installing, and XXXXXX is the build number of the installer ISO image

Your custom installation or upgrade script, the ks_cust.cfg kickstart file


Download the ESXi ISO image from the VMware Web site.


Mount the ISO image in a folder:

mount -o loop VMware-VMvisor-Installer-6.x.x-XXXXXX.x86_64.iso /esxi_cdrom_mount

XXXXXX is the ESXi build number for the version that you are installing or upgrading to.


Copy the contents of cdrom to another folder:

cp -r /esxi_cdrom_mount /esxi_cdrom


Copy the kickstart file to /esxi_cdrom.

cp ks_cust.cfg /esxi_cdrom


(Optional) Modify the boot.cfg file to specify the location of the installation or upgrade script by using the kernelopt option.

You must use uppercase characters to provide the path of the script, for example,

kernelopt=runweasel ks=cdrom:/KS_CUST.CFG

The installation or upgrade becomes completely automatic, without the need to specify the kickstart file during the installation or upgrade.


Recreate the ISO image:

mkisofs -relaxed-filenames -J -R -o custom_esxi.iso -b isolinux.bin -c -no-emul-boot -boot-load-size 4 -boot-info-table /esxi_cdrom

The ISO image includes your custom installation or upgrade script.

Install ESXi from the ISO image.