Client Passthrough

KubeVirt included support for redirecting devices from the client’s machine to the VMI with the support of virtctl command.

USB Redirection

Support for redirection of client’s USB device was introduced in release v0.44. This feature is not enabled by default. To enable it, add an empty clientPassthrough under devices, as such:

  1. spec:
  2.   domain:
  3.     devices:
  4.       clientPassthrough: {}

This configuration currently adds 4 USB slots to the VMI that can only be used with virtctl.

There are two ways of redirecting the same USB devices: Either using its device’s vendor and product information or the actual bus and device address information. In Linux, you can gather this info with lsusb, a redacted example below:

  1. > lsusb
  2. Bus 002 Device 008: ID 0951:1666 Kingston Technology DataTraveler 100 G3/G4/SE9 G2/50
  3. Bus 001 Device 003: ID 13d3:5406 IMC Networks Integrated Camera
  4. Bus 001 Device 010: ID 0781:55ae SanDisk Corp. Extreme 55AE

Using Vendor and Product

Redirecting the Kingston storage device.

  1. virtctl usbredir 0951:1666 vmi-name

Using Bus and Device address

Redirecting the integrated camera

  1. virtctl usbredir 01-03 vmi-name

Requirements for virtctl usbredir

The virtctl command uses an application called usbredirect to handle client’s USB device by unplugging the device from the Client OS and channeling the communication between the device and the VMI.

usbredirect

The usbredirect binary comes from the usbredir project and is supported by most Linux distros. You can either fetch the latest release or MSI installer for Windows support.

Permissions

Managing USB devices requires privileged access in most Operation Systems. The user running virtctl usbredir would need to be privileged or run it in a privileged manner (e.g: with sudo)

Windows support

  • Redirecting USB devices on Windows requires the installation of UsbDk.
  • Be sure to have usbredirect included in the PATH Enviroment Variable.