Chapter 9. Using the Generic Device Plugin

Procedure

1. From your CLI using sudo privileges, open /etc/microshift/config.yaml in a text editor.
2. Locate the genericDevicePlugin section. If it is not present, add it.

3. Set the status parameter to Enabled and define the devices that should be exposed. Each device definition needs a name and one or more groups. Each group can specify devices using paths, for file-based devices, including glob patterns, or usbs, for USB devices using Vendor/Product IDs. You cannot mix paths and usbs within the same device group.

   GDP fields with default values

   apiServer:
   # ...
   genericDevicePlugin:
     devices:
     - groups:
       - paths:
         - path: /dev/ttyUSB* 

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         - path: /dev/ttyACM* 

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       name: serial
     - groups:
       - paths:
         - path: /dev/fuse 

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       name: fuse 

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     - groups:
       - usbs: 

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         - product: "0x7523" 

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           serial: ""
           vendor: "0x1a86" 

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       name: converter
     domain: device.microshift.io 

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     status: Enabled

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   Exposes all the USB serial devices that are matched by this glob.

   2

   Exposes all the ACM serial devices that are matched by this glob.

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   For example, the file path for a fuse device.

   4

   For example, the name of the device.

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   Exposes a specific USB device by Vendor ID and Product ID.

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   For example, the Product ID for a CH340 serial converter

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   For example, the Vendor ID for a CH340 serial converter.

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   Default domain for the GDP.

   Important
   • The output of the microshift show-config parameter might include pre-configured default paths for serial devices even if you have not explicitly configured them in config.yaml. These paths represent the default discovery settings if the Generic Device Plugin is enabled without specific user configuration.
   • For consistency and precise device targeting, especially when dealing with multiple similar devices, consider using stable device paths like /dev/serial/by-id/ or specific USB Vendor, Product, or Serial IDs instead of broad glob patterns like /dev/ttyUSB*.
   • The count parameter in a device group allows a single device, or a set of devices matched by a glob, to be allocated multiple times concurrently to different pods. If omitted, count defaults to 1.
4. Save the config.yaml file.

5. Restart the MicroShift service to apply the changes:

   $ sudo systemctl restart microshift

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   Allow some time for MicroShift to restart and for the GDP to register its devices with the Kubelet.

Procedure

1. Define the device request in your Pod specification:

   apiVersion: v1
   kind: Pod
   metadata:
     name: device-app
   spec:
     containers:
     - name: container
       image: <your_application_image> 

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       command: ["/path/to/your/app"] 

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       args: ["--device_path=/dev/video0"] 

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       resources:
         limits: 

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           device.microshift.io/video: 1 

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       securityContext: 

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         allowPrivilegeEscalation: false
         capabilities:
           drop: ["ALL"]
         runAsNonRoot: true
         seccompProfile:
           type: "RuntimeDefault"

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   Replace with your container image.

   2

   Replace with the command for your application.

   3

   For example, how your application might use the device.

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   The resource name must follow the pattern device.microshift.io/<device_name>, where <device_name> matches the name that you specified in your configuration file.

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   A request for one instance of the video device.

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   Define and configure with the least privilege value to ensure that the container has only required permissions, such as access to the device file, and to restrict other capabilities for the container.

2. Deploy the Kubernetes workload by applying the manifest to the MicroShift node by running the following command:

   $ oc apply -f <your-workload-manifest.yaml> 

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   Replace <your_workload_manifest> with the name of your workload manifest.