ESXi 7.0 Update 2 enhancement for USB NIC only installations

The USB Network Native Driver for ESXi Fling has been an extremely popular Fling that has allowed customers to easily add additional networking capabilities by using a supported USB-based network adapter even though ESXi traffic over USB networking is not officially supported.

In most deployments, the USB network adapter is usually a supplement to the existing onboard network adapter of a system. However, there have been scenarios where the onboard network adapter is either not available or functional and customers would still like to be able to install ESXi and have it running over just the USB network adapter.

Although installing ESXi using just a USB network adapter is possible today, one downside is that an additional workflow is needed to fix the network binding after installing ESXi.

During the interactive ESXi installation, you will see the following error at 81% which will cause installer to get stuck

Exception: No vmknic tagged for management was found.

At this point, the installer has completed and you need to switch to the console (Alt+F1) and perform a reboot. Once ESXi reboots, you will need to go into the DCUI and manually bind the vusb0 interface for ESXi management for connectivity. To persist this USB NIC binding, you will need to add small snippet of code as outlined here.

Obviously, this was not an ideal user experience and I personally had to use this workaround on several occasions, especially for newer hardware platforms where the onboard network adapter may not be recognized by ESXi and being able to use the USB Network Fling definitely came in handy.

With the release of ESXi 7.0 Update 2, we have improved the user experience for installing ESXi with just a single USB NIC. This enhancement was added by Songtao after mentioning the undesirable behavior. A new ESXi kernel boot option called usbBusFullScanOnBootEnabled can be added which removes the need for the workaround mentioned above. This new kernel option forces a full bus scan to claim all USB NICs that are attached since USB device claiming is slow compared to PCIe devices.

This ESXi kernel option must be added during start up and there are two options.

Option 1 - During ESXi Installer boot up, hit Shift + O and then append the following kernel option usbBusFullScanOnBootEnabled=1

Option 2 (recommended) - After creating a bootable USB key with ESXi 7.0 Update 2 installer, mount the USB device and directly edit efi/boot/boot.cfg and simply append usbBusFullScanOnBootEnabled=1 to kernelopt line. This option is great for both scripted and interactive installation, especially since you do not have to manually type it at the console as you could potentially fat finger the longer parameter.