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 just perform a reboot to actually complete the installation.

After ESXi boots up for the first time after the install, 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 to /etc/rc.local.d/local.sh

Standard Virtual Switch (VSS):

vusb0_status=$(esxcli network nic get -n vusb0 | grep 'Link Status' | awk '{print $NF}')
count=0
while [[ $count -lt 20 && "${vusb0_status}" != "Up" ]]
do
    sleep 10
    count=$(( $count + 1 ))
    vusb0_status=$(esxcli network nic get -n vusb0 | grep 'Link Status' | awk '{print $NF}')
done

esxcfg-vswitch -R

Distributed Virtual Switch (VDS):

VDS_0_NAME=vDS
VDS_0_PORT_ID=10
VDS_1_NAME=vDS-NSX
VDS_1_PORT_ID=2

vusb0_status=$(esxcli network nic get -n vusb0 | grep 'Link Status' | awk '{print "v0:" $NF}') && vusb1_status=$(esxcli network nic get -n vusb1 | grep 'Link Status' | awk '{print "v1:" $NF}')
count=0
while [[ $count -lt 40 ]] && [[ "${vusb0_status}" != "v0:Up" || "${vusb1_status}" != "v1:Up" ]]
do
    sleep 5
    count=$(( $count + 1 ))
    vusb0_status=$(esxcli network nic get -n vusb0 | grep 'Link Status' | awk '{print "v0:" $NF}') && vusb1_status=$(esxcli network nic get -n vusb1 | grep 'Link Status' | awk '{print "v1:" $NF}')
done

if [ "${vusb0_status}" = "v0:Up" ]; then
    esxcfg-vswitch -P vusb0 -V ${VDS_0_PORT_ID} ${VDS_0_NAME}
fi

if [ "${vusb1_status}" = "v1:Up" ]; then
    esxcfg-vswitch -P vusb1 -V ${VDS_1_PORT_ID} ${VDS_1_NAME}
fi

Note: The vusbX vmkernel interface may not show up in either ESXi Embedded Host Client and/or vSphere HTML5 UI, this does not mean there is an issue. ESXi was never designed to support USB-based NICs for Management Network and the UI may not properly detect these devices when using the UI. It is recommended to use the ESXi Shell for any operations requiring configuration of vusbX devices.

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 driver parameter called usbBusFullScanOnBootEnabled has been introduced and can added after the initial installation which removes the need for the workaround mentioned above by editing the local.sh file. This new parameter instructs ESXi to perform a full bus scan to claim all USB NICs that are attached since USB device claiming is slow compared to PCIe devices.

To configure the the parameter for the USB Network Fling, run the following ESXCLI command:

esxcli system module parameters set -p "usbBusFullScanOnBootEnabled=1" -m vmkusb_nic_fling

You can confirm the setting has been successfully applied, by running the following command:

esxcli system module parameters list -m vmkusb_nic_fling