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Special Resource Operator

Learn about the Special Resource Operator (SRO) and how you can use it to build and manage driver containers for loading kernel modules and device drivers on nodes in an OKD cluster.

The Special Resource Operator is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.

For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope.

About the Special Resource Operator

The Special Resource Operator (SRO) helps you manage the deployment of kernel modules and drivers on an existing OKD cluster. The SRO can be used for a case as simple as building and loading a single kernel module, or as complex as deploying the driver, device plugin, and monitoring stack for a hardware accelerator.

For loading kernel modules, the SRO is designed around the use of driver containers. Driver containers are increasingly being used in cloud-native environments, especially when run on pure container operating systems, to deliver hardware drivers to the host. Driver containers extend the kernel stack beyond the out-of-the-box software and hardware features of a specific kernel. Driver containers work on various container-capable Linux distributions. With driver containers, the host operating system stays clean and there is no clash between different library versions or binaries on the host.

Installing the Special Resource Operator

As a cluster administrator, you can install the Special Resource Operator (SRO) by using the OpenShift CLI or the web console.

Installing the Special Resource Operator by using the CLI

As a cluster administrator, you can install the Special Resource Operator (SRO) by using the OpenShift CLI.

Prerequisites

  • You have a running OKD cluster.

  • You installed the OpenShift CLI (oc).

  • You are logged into the OpenShift CLI as a user with cluster-admin privileges.

  • You installed the Node Feature Discovery (NFD) Operator.

Procedure

  1. Install the SRO in the openshift-operators namespace:

    1. Create the following Subscription CR and save the YAML in the sro-sub.yaml file:

      Example Subscription CR
      apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
  name: openshift-special-resource-operator
  namespace: openshift-operators
spec:
  channel: "stable"
  installPlanApproval: Automatic
  name: openshift-special-resource-operator
  source: redhat-operators
  sourceNamespace: openshift-marketplace

    2. Create the subscription object by running the following command:

      $ oc create -f sro-sub.yaml

    3. Switch to the openshift-operators project:

      $ oc project openshift-operators
Verification

  • To verify that the Operator deployment is successful, run:

    $ oc get pods
    Example output
    NAME                                                   READY   STATUS    RESTARTS   AGE
nfd-controller-manager-7f4c5f5778-4lvvk                2/2     Running   0          89s
special-resource-controller-manager-6dbf7d4f6f-9kl8h   2/2     Running   0          81s

    A successful deployment shows a Running status.

Installing the Special Resource Operator by using the web console

As a cluster administrator, you can install the Special Resource Operator (SRO) by using the OKD web console.

Prerequisites

  • You installed the Node Feature Discovery (NFD) Operator.

Procedure

  1. Log in to the OKD web console.

  2. Install the Special Resource Operator:

    1. In the OKD web console, click Operators → OperatorHub.

    2. Choose Special Resource Operator from the list of available Operators, and then click Install.

    3. On the Install Operator page, select a specific namespace on the cluster, select the namespace created in the previous section, and then click Install.

Verification

To verify that the Special Resource Operator installed successfully:

  1. Navigate to the Operators → Installed Operators page.

  2. Ensure that Special Resource Operator is listed in the openshift-operators project with a Status of InstallSucceeded.

    During installation, an Operator might display a Failed status. If the installation later succeeds with an InstallSucceeded message, you can ignore the Failed message.

  3. If the Operator does not appear as installed, to troubleshoot further:

    1. Navigate to the Operators → Installed Operators page and inspect the Operator Subscriptions and Install Plans tabs for any failure or errors under Status.

    2. Navigate to the Workloads → Pods page and check the logs for pods in the openshift-operators project.

    The Node Feature Discovery (NFD) Operator is a dependency of the Special Resource Operator (SRO). If the NFD Operator is not installed before installing the SRO, the Operator Lifecycle Manager will automatically install the NFD Operator. However, the required Node Feature Discovery operand will not be deployed automatically. The Node Feature Discovery Operator documentation provides details about how to deploy NFD by using the NFD Operator.

Using the Special Resource Operator

The Special Resource Operator (SRO) is used to manage the build and deployment of a driver container. The objects required to build and deploy the container can be defined in a Helm chart.

The example in this section uses the simple-kmod SpecialResource object to point to a ConfigMap object that is created to store the Helm charts.

Building and running the simple-kmod SpecialResource by using a config map

In this example, the simple-kmod kernel module shows how the Special Resource Operator (SRO) manages a driver container. The container is defined in the Helm chart templates that are stored in a config map.

Prerequisites

  • You have a running OKD 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.

  • You installed the Node Feature Discovery (NFD) Operator.

  • You installed the SRO.

  • You installed the Helm CLI (helm).

Procedure

  1. To create a simple-kmod SpecialResource object, define an image stream and build config to build the image, and a service account, role, role binding, and daemon set to run the container. The service account, role, and role binding are required to run the daemon set with the privileged security context so that the kernel module can be loaded.

    1. Create a templates directory, and change into it:

      $ mkdir -p chart/simple-kmod-0.0.1/templates
      $ cd chart/simple-kmod-0.0.1/templates

    2. Save this YAML template for the image stream and build config in the templates directory as 0000-buildconfig.yaml:

      apiVersion: image.openshift.io/v1
kind: ImageStream
metadata:
  labels:
    app: {{.Values.specialresource.metadata.name}}-{{.Values.groupName.driverContainer}} (1)
  name: {{.Values.specialresource.metadata.name}}-{{.Values.groupName.driverContainer}} (1)
spec: {}
---
apiVersion: build.openshift.io/v1
kind: BuildConfig
metadata:
  labels:
    app: {{.Values.specialresource.metadata.name}}-{{.Values.groupName.driverBuild}}  (1)
  name: {{.Values.specialresource.metadata.name}}-{{.Values.groupName.driverBuild}} (1)
  annotations:
    specialresource.openshift.io/wait: "true"
    specialresource.openshift.io/driver-container-vendor: simple-kmod
    specialresource.openshift.io/kernel-affine: "true"
spec:
  nodeSelector:
    node-role.kubernetes.io/worker: ""
  runPolicy: "Serial"
  triggers:
    - type: "ConfigChange"
    - type: "ImageChange"
  source:
    git:
      ref: {{.Values.specialresource.spec.driverContainer.source.git.ref}}
      uri: {{.Values.specialresource.spec.driverContainer.source.git.uri}}
    type: Git
  strategy:
    dockerStrategy:
      dockerfilePath: Dockerfile.SRO
      buildArgs:
        - name: "IMAGE"
          value: {{ .Values.driverToolkitImage  }}
        {{- range $arg := .Values.buildArgs }}
        - name: {{ $arg.name }}
          value: {{ $arg.value }}
        {{- end }}
        - name: KVER
          value: {{ .Values.kernelFullVersion }}
  output:
    to:
      kind: ImageStreamTag
      name: {{.Values.specialresource.metadata.name}}-{{.Values.groupName.driverContainer}}:v{{.Values.kernelFullVersion}} (1)
      1 The templates such as {{.Values.specialresource.metadata.name}} are filled in by the SRO, based on fields in the SpecialResource CR and variables known to the Operator such as {{.Values.KernelFullVersion}}.

    3. Save the following YAML template for the RBAC resources and daemon set in the templates directory as 1000-driver-container.yaml:

      apiVersion: v1
kind: ServiceAccount
metadata:
  name: {{.Values.specialresource.metadata.name}}-{{.Values.groupName.driverContainer}}
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: {{.Values.specialresource.metadata.name}}-{{.Values.groupName.driverContainer}}
rules:
- apiGroups:
  - security.openshift.io
  resources:
  - securitycontextconstraints
  verbs:
  - use
  resourceNames:
  - privileged
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: {{.Values.specialresource.metadata.name}}-{{.Values.groupName.driverContainer}}
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: {{.Values.specialresource.metadata.name}}-{{.Values.groupName.driverContainer}}
subjects:
- kind: ServiceAccount
  name: {{.Values.specialresource.metadata.name}}-{{.Values.groupName.driverContainer}}
  namespace: {{.Values.specialresource.spec.namespace}}
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
  labels:
    app: {{.Values.specialresource.metadata.name}}-{{.Values.groupName.driverContainer}}
  name: {{.Values.specialresource.metadata.name}}-{{.Values.groupName.driverContainer}}
  annotations:
    specialresource.openshift.io/wait: "true"
    specialresource.openshift.io/state: "driver-container"
    specialresource.openshift.io/driver-container-vendor: simple-kmod
    specialresource.openshift.io/kernel-affine: "true"
    specialresource.openshift.io/from-configmap: "true"
spec:
  updateStrategy:
    type: OnDelete
  selector:
    matchLabels:
      app: {{.Values.specialresource.metadata.name}}-{{.Values.groupName.driverContainer}}
  template:
    metadata:
      labels:
        app: {{.Values.specialresource.metadata.name}}-{{.Values.groupName.driverContainer}}
    spec:
      priorityClassName: system-node-critical
      serviceAccount: {{.Values.specialresource.metadata.name}}-{{.Values.groupName.driverContainer}}
      serviceAccountName: {{.Values.specialresource.metadata.name}}-{{.Values.groupName.driverContainer}}
      containers:
      - image: image-registry.openshift-image-registry.svc:5000/{{.Values.specialresource.spec.namespace}}/{{.Values.specialresource.metadata.name}}-{{.Values.groupName.driverContainer}}:v{{.Values.kernelFullVersion}}
        name: {{.Values.specialresource.metadata.name}}-{{.Values.groupName.driverContainer}}
        imagePullPolicy: Always
        command: ["/sbin/init"]
        lifecycle:
          preStop:
            exec:
              command: ["/bin/sh", "-c", "systemctl stop kmods-via-containers@{{.Values.specialresource.metadata.name}}"]
        securityContext:
          privileged: true
      nodeSelector:
        node-role.kubernetes.io/worker: ""
        feature.node.kubernetes.io/kernel-version.full: "{{.Values.KernelFullVersion}}"

    4. Change into the chart/simple-kmod-0.0.1 directory:

      $ cd ..

    5. Save the following YAML for the chart as Chart.yaml in the chart/simple-kmod-0.0.1 directory:

      apiVersion: v2
name: simple-kmod
description: Simple kmod will deploy a simple kmod driver-container
icon: https://avatars.githubusercontent.com/u/55542927
type: application
version: 0.0.1
appVersion: 1.0.0

  2. From the chart directory, create the chart using the helm package command:

    $ helm package simple-kmod-0.0.1/
    Example output
    Successfully packaged chart and saved it to: /data/<username>/git/<github_username>/special-resource-operator/yaml-for-docs/chart/simple-kmod-0.0.1/simple-kmod-0.0.1.tgz

  3. Create a config map to store the chart files:

    1. Create a directory for the config map files:

      $ mkdir cm

    2. Copy the Helm chart into the cm directory:

      $ cp simple-kmod-0.0.1.tgz cm/simple-kmod-0.0.1.tgz

    3. Create an index file specifying the Helm repo that contains the Helm chart:

      $ helm repo index cm --url=cm://simple-kmod/simple-kmod-chart

    4. Create a namespace for the objects defined in the Helm chart:

      $ oc create namespace simple-kmod

    5. Create the config map object:

      $ oc create cm simple-kmod-chart --from-file=cm/index.yaml --from-file=cm/simple-kmod-0.0.1.tgz -n simple-kmod

  4. Use the following SpecialResource manifest to deploy the simple-kmod object using the Helm chart that you created in the config map. Save this YAML as simple-kmod-configmap.yaml:

    apiVersion: sro.openshift.io/v1beta1
kind: SpecialResource
metadata:
  name: simple-kmod
spec:
  #debug: true (1)
  namespace: simple-kmod
  chart:
    name: simple-kmod
    version: 0.0.1
    repository:
      name: example
      url: cm://simple-kmod/simple-kmod-chart (2)
  set:
    kind: Values
    apiVersion: sro.openshift.io/v1beta1
    kmodNames: ["simple-kmod", "simple-procfs-kmod"]
    buildArgs:
    - name: "KMODVER"
      value: "SRO"
  driverContainer:
    source:
      git:
        ref: "master"
        uri: "https://github.com/openshift-psap/kvc-simple-kmod.git"
    1 Optional: Uncomment the #debug: true line to have the YAML files in the chart printed in full in the Operator logs and to verify that the logs are created and templated properly.
    2 The spec.chart.repository.url field tells the SRO to look for the chart in a config map.

  5. From a command line, create the SpecialResource file:

    $ oc create -f simple-kmod-configmap.yaml

To remove the simple-kmod kernel module from the node, delete the simple-kmod SpecialResource API object using the oc delete command. The kernel module is unloaded when the driver container pod is deleted.
Verification

The simple-kmod resources are deployed in the simple-kmod namespace as specified in the object manifest. After a short time, the build pod for the simple-kmod driver container starts running. The build completes after a few minutes, and then the driver container pods start running.

  1. Use oc get pods command to display the status of the build pods:

    $ oc get pods -n simple-kmod
    Example output
    NAME                                                  READY   STATUS      RESTARTS   AGE
simple-kmod-driver-build-12813789169ac0ee-1-build     0/1     Completed   0          7m12s
simple-kmod-driver-container-12813789169ac0ee-mjsnh   1/1     Running     0          8m2s
simple-kmod-driver-container-12813789169ac0ee-qtkff   1/1     Running     0          8m2s

  2. Use the oc logs command, along with the build pod name obtained from the oc get pods command above, to display the logs of the simple-kmod driver container image build:

    $ oc logs pod/simple-kmod-driver-build-12813789169ac0ee-1-build -n simple-kmod

  3. To verify that the simple-kmod kernel modules are loaded, execute the lsmod command in one of the driver container pods that was returned from the oc get pods command above:

    $ oc exec -n simple-kmod -it pod/simple-kmod-driver-container-12813789169ac0ee-mjsnh -- lsmod | grep simple
    Example output
    simple_procfs_kmod     16384  0
simple_kmod            16384  0

The sro_kind_completed_info SRO Prometheus metric provides information about the status of the different objects being deployed, which can be useful to troubleshoot SRO CR installations. The SRO also provides other types of metrics that you can use to watch the health of your environment.

Prometheus Special Resource Operator metrics

The Special Resource Operator (SRO) exposes the following Prometheus metrics through the metrics service:

Metric Name Description

sro_used_nodes

Returns the nodes that are running pods created by a SRO custom resource (CR). This metric is available for DaemonSet and Deployment objects only.

sro_kind_completed_info

Represents whether a kind of an object defined by the Helm Charts in a SRO CR has been successfully uploaded in the cluster (value 1) or not (value 0). Examples of objects are DaemonSet, Deployment or BuildConfig.

sro_states_completed_info

Represents whether the SRO has finished processing a CR successfully (value 1) or the SRO has not processed the CR yet (value 0).

sro_managed_resources_total

Returns the number of SRO CRs in the cluster, regardless of their state.

Additional resources