Firmware support

Kernel modules sometimes need to load firmware files from the filesystem. KMM supports copying firmware files from the kmod image to the node's filesystem.
The contents of .spec.moduleLoader.container.modprobe.firmwarePath are copied on the node into the path specified in the kmm-operator-manager-config configMap at worker.setFirmwareClassPath before modprobe is called to insert the kernel module. All files and empty directories are removed from that location before modprobe -r is called to unload the kernel module, when the pod is terminated.

Building a kmod image

In addition to building the kernel module itself, include the binary firmware in the builder image.

FROM ubuntu as builder

# Build the kmod

RUN ["mkdir", "/firmware"]
RUN ["curl", "-o", "/firmware/firmware.bin", "https://artifacts.example.com/firmware.bin"]

FROM ubuntu

# Copy the kmod, install modprobe, run depmod

COPY --from=builder /firmware /firmware

Tuning the Module resource

Set .spec.moduleLoader.container.modprobe.firmwarePath in the Module CR:

apiVersion: kmm.sigs.x-k8s.io/v1beta1
kind: Module
metadata:
  name: my-kmod
spec:
  moduleLoader:
    container:
      modprobe:
        moduleName: my-kmod  # Required

        # Optional. Will copy /firmware/* on the node into the path specified
        # in the `kmm-operator-manager-config` at `worker.setFirmwareClassPath`
        # before `modprobe` is called to insert the kernel module..
        firmwarePath: /firmware

        # Add kernel mappings
  selector:
    node-role.kubernetes.io/worker: ""

Setting the kernel's firmware search path

The Linux kernel accepts the firmware_class.path parameter as a search path for firmwares. Since version 2.0.0, KMM workers can set that value on nodes by writing to sysfs, before attempting to load kmods.
To enable that feature, set worker.setFirmwareClassPath in the operator configuration.
The default value is /lib/firmware