ESXi Install or Upgrade Over PXE

I have been using this technique since version 4 and at this point I find it to be a time tested method of deploying or upgrading ESXi. With that said, I figure it is time to share. If you have a site with more than one ESXi box and a PXE system, then this tutorial may be for you. The process is much easier then you might think, first you need to head over to VMware and download the latest version of ESXi. Once you have downloaded the ESXi installer, you will want to extract the .iso to a folder called “esx”. In the folder esx we will be looking for a file called BOOT.CFG. This file tells the ESXi kernel where all the packages are to load at boot. This file will need to be modified in order to use it over PXE. Open the BOOT.CFG file with Notepad++ and find an replace (CTRL+ H) the “/” with “” as pictured below. Click “Replace All”.

Once replaced, save the file and then copy the “esx” folder over to the “TFTProot” of your “PXEServer”. Now open your pxelinux configuration file which will be called “default” if you followed my tutorial here. Inside this file, add an entry for ESXi as seen below.

LABEL esx
#SET PASSWORD FOR THIS OPTION
MENU PASSWD In$t@llM3
MENU LABEL ESXi 5.5 Install/Upgrade Image
kernel images/esx/mboot.c32
append -c images/esx/boot.cfg

Once that is complete you should be able to boot to ESXi using your PXE Server. Note that in the past when using tftpd-hpa (Linux PXE Server) there have been case-sensitivity issues booting ESXi. I have used the method described here under the heading “The TFTP Remap File” with a 100% success rate.