Install VMware ESXi to a USB Flash Drive on a Hetzner PX121 Root Server without a Virtual CD/Mounted ISO

09 Feb 2018

I recently had a problem with a new Hetzner Root Server from the PX121 product line, where I tried to install VMware ESXi from a mounted ISO on the Hetzner Lantronix KVM console.

Everytime I mounted the ISO, the keyboard stopped working inside of the KVM console session. So I contacted Hetzner Support, which claimed that “installing from a mounted ISO is not officially supported, so there is nothing they could do about it”, also, “mounting an ISO on the KVM console has a known bug, where it’s disabling all other USB devices on the KVM device” :( …Which basically means that installing ESXi from a mounted ISO is off the table.

My initial plan was to install ESXi to a USB drive I ordered with the server, so I would have a clean system on the USB drive and a full RAID-10 as a datastore, separated from it. Of cause I could’ve just dd the ESXi ISO on the USB drive and boot from that, but than I would’ve been forced to install ESXi on the RAID directly, which I wanted to avoid by any means.

So the only option left was this trick: Make the RAID the bootable ESXi installer, boot from it and install ESXi on the USB drive from there.

This is how made the RAID a bootable ESXi installer disk:

1. Boot the Server into Rescue mode and login via SSH.
2. Install required packages:

   apt-get install dosfstools mtools syslinux
   

3. Download the ESXi ISO:

   curl --progress-bar -o VMware-VMvisor-Installer-6.5.0-4564106.x86_64.iso https://mirror.hetzner.de/bootimages/vmware/VMware-VMvisor-Installer-6.5.0-4564106.x86_64.iso
   

4. Create partition Table with fdisk /dev/sda:

   d
   o
   n
   p
   2048
   +2G
   w
   

5. Reload partition table:

   partprobe && sync
   

6. Format partition as FAT:

   mkfs.vfat -F 32 /dev/sda1
   

7. Install Syslinux Bootloader on partition /dev/sda1:

   syslinux /dev/sda1
   

8. Write MBR to RAID disk:

   dd if=/usr/lib/syslinux/mbr/mbr.bin of=/dev/sda
   

9. Create mount points:

   mkdir -p /mnt/{iso,raid}
   

10. Mount ESXi ISO:

    mount -o loop VMware-VMvisor-Installer-6.5.0-4564106.x86_64.iso /mnt/iso
    

11. Mount /dev/sda1:

    mount /dev/sda1 /mnt/raid
    

12. Copy files from ESXi ISO to RAID disk:

    cp -r /mnt/iso/* /mnt/raid/
    

13. Copy Sylinux files:

    cp /mnt/raid/isolinux.cfg /mnt/raid/syslinux.cfg
    cp /usr/lib/syslinux/modules/bios/*.c32 /mnt/raid/
    

14. Unmount RAID:

    umount /mnt/raid
    sync
    

15. reboot
16. Boot from RAID drive.
17. Install ESXi to the USB drive.
18. After ESXi is installed successfully, boot into Rescue mode again to wipe the RAID drive’s partition table (so it can be initialized as datastore in ESXi, like it was supposed to):

    dd if=/dev/zero of=/dev/sda bs=16 count=16 && sync
    

19. Reboot
20. Run ESXi from USB drive & have fun!

1. https://raymii.org/s/tutorials/VMWare-ESXi-5-USB-installer.html