Chapter 2. Driver Toolkit
Chapter 2. Driver Toolkit Learn about the Driver Toolkit and how you can use it as a base image for driver containers for enabling special software and hardware devices on OpenShift Container Platform deployments. 2.1. About the Driver Toolkit Background The Driver Toolkit is a container image in the OpenShift Container Platform payload used as a base image on which you can build driver containers. The Driver Toolkit image includes the kernel packages commonly required as dependencies to build or install kernel modules, as well as a few tools needed in driver containers. The version of these packages will match the kernel version running on the Red Hat Enterprise Linux CoreOS (RHCOS) nodes in the corresponding OpenShift Container Platform release. Driver containers are container images used for building and deploying out-of-tree kernel modules and drivers on container operating systems like RHCOS. Kernel modules and drivers are software libraries running with a high level of privilege in the operating system kernel. They extend the kernel functionalities or provide the hardware-specific code required to control new devices. Examples include hardware devices like Field Programmable Gate Arrays (FPGA) or GPUs, and software-defined storage (SDS) solutions, such as Lustre parallel file systems, which require kernel modules on client machines. Driver containers are the first layer of the software stack used to enable these technologies on Kubernetes. The list of kernel packages in the Driver Toolkit includes the following and their dependencies: kernel-core kernel-devel kernel-headers kernel-modules kernel-modules-extra In addition, the Driver Toolkit also includes the corresponding real-time kernel packages: kernel-rt-core kernel-rt-devel kernel-rt-modules kernel-rt-modules-extra The Driver Toolkit also has several tools that are commonly needed to build and install kernel modules, including: elfutils-libelf-devel kmod binutilskabi-dw kernel-abi-whitelists dependencies for the above Purpose Prior to the Driver Toolkit's existence, users would install kernel packages in a pod or build config on OpenShift Container Platform using entitled builds or by installing from the kernel RPMs in the hosts machine-os-content . The Driver Toolkit simplifies the process by removing the entitlement step, and avoids the privileged operation of accessing the machine-os-content in a pod. The Driver Toolkit can also be used by partners who have access to pre-released OpenShift Container Platform versions to prebuild driver-containers for their hardware devices for future OpenShift Container Platform releases. The Driver Toolkit is also used by the Kernel Module Management (KMM), which is currently available as a community Operator on OperatorHub. KMM supports out-of-tree and third-party kernel drivers and the support software for the underlying operating system. Users can create modules for KMM to build and deploy a driver container, as well as support software like a device plugin, or metrics. Modules can include a build config to build a driver container-based on the Driver Toolkit, or KMM can deploy a prebuilt driver container. 2.2. Pulling the Driver Toolkit container image The driver-toolkit image is available from the Container images section of the Red Hat Ecosystem Catalog and in the OpenShift Container Platform release payload. The image corresponding to the most recent minor release of OpenShift Container Platform will be tagged with the version number in the catalog. The image URL for a specific release can be found using the oc adm CLI command. 2.2.1. Pulling the Driver Toolkit container image from registry.redhat.io Instructions for pulling the driver-toolkit image from registry.redhat.io with podman or in OpenShift Container Platform can be found on the Red Hat Ecosystem Catalog . The driver-toolkit image for the latest minor release are tagged with the minor release version on registry.redhat.io , for example: registry.redhat.io/openshift4/driver-toolkit-rhel8:v4.17 . 2.2.2. Finding the Driver Toolkit image URL in the payload Prerequisites You obtained the image pull secret from Red Hat OpenShift Cluster Manager . You installed the OpenShift CLI ( oc ). Procedure Use the oc adm command to extract the image URL of the driver-toolkit corresponding to a certain release: For an x86 image, the command is as follows: USD oc adm release info quay.io/openshift-release-dev/ocp-release:4.17.z-x86_64 --image-for=driver-toolkit For an ARM image, the command is as follows: USD oc adm release info quay.io/openshift-release-dev/ocp-release:4.17.z-aarch64 --image-for=driver-toolkit Example output quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:b53883ca2bac5925857148c4a1abc300ced96c222498e3bc134fe7ce3a1dd404 Obtain this image using a valid pull secret, such as the pull secret required to install OpenShift Container Platform: USD podman pull --authfile=path/to/pullsecret.json quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:<SHA> 2.3. Using the Driver Toolkit As an example, the Driver Toolkit can be used as the base image for building a very simple kernel module called simple-kmod . Note The Driver Toolkit includes the necessary dependencies, openssl , mokutil , and keyutils , needed to sign a kernel module. However, in this example, the simple-kmod kernel module is not signed and therefore cannot be loaded on systems with Secure Boot enabled. 2.3.1. Build and run the simple-kmod driver container on a cluster Prerequisites You have a running OpenShift Container Platform cluster. You set the Image Registry Operator state to Managed for your cluster. You installed the OpenShift CLI ( oc ). You are logged into the OpenShift CLI as a user with cluster-admin privileges. Procedure Create a namespace. For example: USD oc new-project simple-kmod-demo The YAML defines an ImageStream for storing the simple-kmod driver container image, and a BuildConfig for building the container. Save this YAML as 0000-buildconfig.yaml.template . apiVersion: image.openshift.io/v1 kind: ImageStream metadata: labels: app: simple-kmod-driver-container name: simple-kmod-driver-container namespace: simple-kmod-demo spec: {} --- apiVersion: build.openshift.io/v1 kind: BuildConfig metadata: labels: app: simple-kmod-driver-build name: simple-kmod-driver-build namespace: simple-kmod-demo spec: nodeSelector: node-role.kubernetes.io/worker: "" runPolicy: "Serial" triggers: - type: "ConfigChange" - type: "ImageChange" source: dockerfile: | ARG DTK FROM USD{DTK} as builder ARG KVER WORKDIR /build/ RUN git clone https://github.com/openshift-psap/simple-kmod.git WORKDIR /build/simple-kmod RUN make all install KVER=USD{KVER} FROM registry.redhat.io/ubi8/ubi-minimal ARG KVER # Required for installing `modprobe` RUN microdnf install kmod COPY --from=builder /lib/modules/USD{KVER}/simple-kmod.ko /lib/modules/USD{KVER}/ COPY --from=builder /lib/modules/USD{KVER}/simple-procfs-kmod.ko /lib/modules/USD{KVER}/ RUN depmod USD{KVER} strategy: dockerStrategy: buildArgs: - name: KMODVER value: DEMO # USD oc adm release info quay.io/openshift-release-dev/ocp-release:<cluster version>-x86_64 --image-for=driver-toolkit - name: DTK value: quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:34864ccd2f4b6e385705a730864c04a40908e57acede44457a783d739e377cae - name: KVER value: 4.18.0-372.26.1.el8_6.x86_64 output: to: kind: ImageStreamTag name: simple-kmod-driver-container:demo Substitute the correct driver toolkit image for the OpenShift Container Platform version you are running in place of "DRIVER_TOOLKIT_IMAGE" with the following commands. USD OCP_VERSION=USD(oc get clusterversion/version -ojsonpath={.status.desired.version}) USD DRIVER_TOOLKIT_IMAGE=USD(oc adm release info USDOCP_VERSION --image-for=driver-toolkit) USD sed "s#DRIVER_TOOLKIT_IMAGE#USD{DRIVER_TOOLKIT_IMAGE}#" 0000-buildconfig.yaml.template > 0000-buildconfig.yaml Create the image stream and build config with USD oc create -f 0000-buildconfig.yaml After the builder pod completes successfully, deploy the driver container image as a DaemonSet . The driver container must run with the privileged security context in order to load the kernel modules on the host. The following YAML file contains the RBAC rules and the DaemonSet for running the driver container. Save this YAML as 1000-drivercontainer.yaml . apiVersion: v1 kind: ServiceAccount metadata: name: simple-kmod-driver-container --- apiVersion: rbac.authorization.k8s.io/v1 kind: Role metadata: name: simple-kmod-driver-container rules: - apiGroups: - security.openshift.io resources: - securitycontextconstraints verbs: - use resourceNames: - privileged --- apiVersion: rbac.authorization.k8s.io/v1 kind: RoleBinding metadata: name: simple-kmod-driver-container roleRef: apiGroup: rbac.authorization.k8s.io kind: Role name: simple-kmod-driver-container subjects: - kind: ServiceAccount name: simple-kmod-driver-container userNames: - system:serviceaccount:simple-kmod-demo:simple-kmod-driver-container --- apiVersion: apps/v1 kind: DaemonSet metadata: name: simple-kmod-driver-container spec: selector: matchLabels: app: simple-kmod-driver-container template: metadata: labels: app: simple-kmod-driver-container spec: serviceAccount: simple-kmod-driver-container serviceAccountName: simple-kmod-driver-container containers: - image: image-registry.openshift-image-registry.svc:5000/simple-kmod-demo/simple-kmod-driver-container:demo name: simple-kmod-driver-container imagePullPolicy: Always command: [sleep, infinity] lifecycle: postStart: exec: command: ["modprobe", "-v", "-a" , "simple-kmod", "simple-procfs-kmod"] preStop: exec: command: ["modprobe", "-r", "-a" , "simple-kmod", "simple-procfs-kmod"] securityContext: privileged: true nodeSelector: node-role.kubernetes.io/worker: "" Create the RBAC rules and daemon set: USD oc create -f 1000-drivercontainer.yaml After the pods are running on the worker nodes, verify that the simple_kmod kernel module is loaded successfully on the host machines with lsmod . Verify that the pods are running: USD oc get pod -n simple-kmod-demo Example output NAME READY STATUS RESTARTS AGE simple-kmod-driver-build-1-build 0/1 Completed 0 6m simple-kmod-driver-container-b22fd 1/1 Running 0 40s simple-kmod-driver-container-jz9vn 1/1 Running 0 40s simple-kmod-driver-container-p45cc 1/1 Running 0 40s Execute the lsmod command in the driver container pod: USD oc exec -it pod/simple-kmod-driver-container-p45cc -- lsmod | grep simple Example output simple_procfs_kmod 16384 0 simple_kmod 16384 0 2.4. Additional resources For more information about configuring registry storage for your cluster, see Image Registry Operator in OpenShift Container Platform .
oc adm release info quay.io/openshift-release-dev/ocp-release:4.17.z-x86_64 --image-for=driver-toolkit oc adm release info quay.io/openshift-release-dev/ocp-release:4.17.z-aarch64 --image-for=driver-toolkit quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:b53883ca2bac5925857148c4a1abc300ced96c222498e3bc134fe7ce3a1dd404 podman pull --authfile=path/to/pullsecret.json quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:<SHA> oc new-project simple-kmod-demo apiVersion: image.openshift.io/v1 kind: ImageStream metadata: labels: app: simple-kmod-driver-container name: simple-kmod-driver-container namespace: simple-kmod-demo spec: {} --- apiVersion: build.openshift.io/v1 kind: BuildConfig metadata: labels: app: simple-kmod-driver-build name: simple-kmod-driver-build namespace: simple-kmod-demo spec: nodeSelector: node-role.kubernetes.io/worker: "" runPolicy: "Serial" triggers: - type: "ConfigChange" - type: "ImageChange" source: dockerfile: | ARG DTK FROM USD{DTK} as builder ARG KVER WORKDIR /build/ RUN git clone https://github.com/openshift-psap/simple-kmod.git WORKDIR /build/simple-kmod RUN make all install KVER=USD{KVER} FROM registry.redhat.io/ubi8/ubi-minimal ARG KVER # Required for installing `modprobe` RUN microdnf install kmod COPY --from=builder /lib/modules/USD{KVER}/simple-kmod.ko /lib/modules/USD{KVER}/ COPY --from=builder /lib/modules/USD{KVER}/simple-procfs-kmod.ko /lib/modules/USD{KVER}/ RUN depmod USD{KVER} strategy: dockerStrategy: buildArgs: - name: KMODVER value: DEMO # USD oc adm release info quay.io/openshift-release-dev/ocp-release:<cluster version>-x86_64 --image-for=driver-toolkit - name: DTK value: quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:34864ccd2f4b6e385705a730864c04a40908e57acede44457a783d739e377cae - name: KVER value: 4.18.0-372.26.1.el8_6.x86_64 output: to: kind: ImageStreamTag name: simple-kmod-driver-container:demo OCP_VERSION=USD(oc get clusterversion/version -ojsonpath={.status.desired.version}) DRIVER_TOOLKIT_IMAGE=USD(oc adm release info USDOCP_VERSION --image-for=driver-toolkit) sed "s#DRIVER_TOOLKIT_IMAGE#USD{DRIVER_TOOLKIT_IMAGE}#" 0000-buildconfig.yaml.template > 0000-buildconfig.yaml oc create -f 0000-buildconfig.yaml apiVersion: v1 kind: ServiceAccount metadata: name: simple-kmod-driver-container --- apiVersion: rbac.authorization.k8s.io/v1 kind: Role metadata: name: simple-kmod-driver-container rules: - apiGroups: - security.openshift.io resources: - securitycontextconstraints verbs: - use resourceNames: - privileged --- apiVersion: rbac.authorization.k8s.io/v1 kind: RoleBinding metadata: name: simple-kmod-driver-container roleRef: apiGroup: rbac.authorization.k8s.io kind: Role name: simple-kmod-driver-container subjects: - kind: ServiceAccount name: simple-kmod-driver-container userNames: - system:serviceaccount:simple-kmod-demo:simple-kmod-driver-container --- apiVersion: apps/v1 kind: DaemonSet metadata: name: simple-kmod-driver-container spec: selector: matchLabels: app: simple-kmod-driver-container template: metadata: labels: app: simple-kmod-driver-container spec: serviceAccount: simple-kmod-driver-container serviceAccountName: simple-kmod-driver-container containers: - image: image-registry.openshift-image-registry.svc:5000/simple-kmod-demo/simple-kmod-driver-container:demo name: simple-kmod-driver-container imagePullPolicy: Always command: [sleep, infinity] lifecycle: postStart: exec: command: ["modprobe", "-v", "-a" , "simple-kmod", "simple-procfs-kmod"] preStop: exec: command: ["modprobe", "-r", "-a" , "simple-kmod", "simple-procfs-kmod"] securityContext: privileged: true nodeSelector: node-role.kubernetes.io/worker: "" oc create -f 1000-drivercontainer.yaml oc get pod -n simple-kmod-demo NAME READY STATUS RESTARTS AGE simple-kmod-driver-build-1-build 0/1 Completed 0 6m simple-kmod-driver-container-b22fd 1/1 Running 0 40s simple-kmod-driver-container-jz9vn 1/1 Running 0 40s simple-kmod-driver-container-p45cc 1/1 Running 0 40s oc exec -it pod/simple-kmod-driver-container-p45cc -- lsmod | grep simple simple_procfs_kmod 16384 0 simple_kmod 16384 0