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Kernel Module Management Operator

The Kernel Module Management (KMM) Operator deploys out-of-tree kernel modules and device plugins on OpenShift Container Platform clusters. You can use KMM to build, load, and manage kernel modules across cluster lifecycle stages.

About the Kernel Module Management Operator​

The Kernel Module Management (KMM) Operator on OpenShift Container Platform manages the full lifecycle of out-of-tree kernel modules and device plugins, from build and signing through deployment.

You can use Module custom resources (CRs)to define module loaders, device plugins, and version-specific build instructions across kernel upgrades.

Install the Kernel Module Management Operator​

As a cluster administrator, you can install the Kernel Module Management (KMM) Operator on OpenShift Container Platform by using the OpenShift CLI or web console.

The KMM Operator is supported on OpenShift Container Platform 4.12 and later. Installing KMM on version 4.11 does not require specific additional steps. For details on installing KMM on version 4.10 and earlier, see the section "Installing the Kernel Module Management Operator on earlier versions of OpenShift Container Platform".

Installing the Kernel Module Management Operator using the web console​

To install the Kernel Module Management (KMM)Operator on OpenShift Container Platform, you can use the web console Software Catalog to deploy it into the openshift-kmm namespace.

Procedure

  1. Log in to the OpenShift Container Platform web console.
  2. Install the Kernel Module Management Operator:
    1. In the OpenShift Container Platform web console, click Ecosystem → Software Catalog.
    2. Select Kernel Module Management Operator from the list of available Operators, and then click Install.
    3. From the Installed Namespace list, select the openshift-kmm namespace.
    4. Click Install.

Verification

To verify that KMM Operator installed successfully:

  1. Navigate to the Ecosystem → Installed Operators page.

  2. Ensure that Kernel Module Management Operator is listed in the openshift-kmm project with a Status of InstallSucceeded.

    note

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

Troubleshooting

  1. To troubleshoot issues with Operator installation:
    1. Navigate to the Ecosystem → 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-kmm project.

Installing the Kernel Module Management Operator by using the CLI​

To install the Kernel Module Management (KMM) Operator on OpenShift Container Platform, you can create Namespace, OperatorGroup, and Subscription resources by using the OpenShift CLI (oc).

Prerequisites

  • You have a running OpenShift Container Platform cluster.
  • You installed the OpenShift CLI (oc).
  • You are logged into the OpenShift CLI as a user with cluster-admin privileges.

Procedure

  1. Install KMM in the openshift-kmm namespace:
    1. Create the following Namespace CR and save the YAML file, for example, kmm-namespace.yaml: 
      apiVersion: v1
      kind: Namespace
      metadata:
        name: openshift-kmm
    2. Create the following OperatorGroup CR and save the YAML file, for example, kmm-op-group.yaml: 
      apiVersion: operators.coreos.com/v1
      kind: OperatorGroup
      metadata:
        name: kernel-module-management
        namespace: openshift-kmm
    3. Create the following Subscription CR and save the YAML file, for example, kmm-sub.yaml: 
      apiVersion: operators.coreos.com/v1alpha1
      kind: Subscription
      metadata:
        name: kernel-module-management
        namespace: openshift-kmm
      spec:
        channel: stable
        installPlanApproval: Automatic
        name: kernel-module-management
        source: redhat-operators
        sourceNamespace: openshift-marketplace
    4. Create the subscription object by running the following command: 
      $ oc create -f kmm-sub.yaml

Verification

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

    $ oc get -n openshift-kmm deployments.apps kmm-operator-controller

    Example output:

    NAME                              READY UP-TO-DATE  AVAILABLE AGE
    kmm-operator-controller           1/1   1           1         97s

    The Operator is available.

Install the Kernel Module Management Operator on earlier versions of OpenShift Container Platform​

As a cluster administrator, you can install the Kernel Module Management (KMM) Operator by using the OpenShift CLI.

The KMM Operator is supported on OpenShift Container Platform 4.12 and later. For version 4.10 and earlier, you must create a new SecurityContextConstraint object and bind it to the Operator’s ServiceAccount.

Prerequisites

  • You have a running OpenShift Container Platform cluster.
  • You installed the OpenShift CLI (oc).
  • You are logged into the OpenShift CLI as a user with cluster-admin privileges.

Procedure

  1. Install KMM in the openshift-kmm namespace:

    1. Create the following Namespace CR and save the YAML file, for example, kmm-namespace.yaml file:

      apiVersion: v1
      kind: Namespace
      metadata:
        name: openshift-kmm

    2. Create the following SecurityContextConstraint object and save the YAML file, for example, kmm-security-constraint.yaml:

      allowHostDirVolumePlugin: false
      allowHostIPC: false
      allowHostNetwork: false
      allowHostPID: false
      allowHostPorts: false
      allowPrivilegeEscalation: false
      allowPrivilegedContainer: false
      allowedCapabilities:
        - NET_BIND_SERVICE
      apiVersion: security.openshift.io/v1
      defaultAddCapabilities: null
      fsGroup:
        type: MustRunAs
      groups: []
      kind: SecurityContextConstraints
      metadata:
        name: restricted-v2
      priority: null
      readOnlyRootFilesystem: false
      requiredDropCapabilities:
        - ALL
      runAsUser:
        type: MustRunAsRange
      seLinuxContext:
        type: MustRunAs
      seccompProfiles:
        - runtime/default
      supplementalGroups:
        type: RunAsAny
      users: []
      volumes:
        - configMap
        - downwardAPI
        - emptyDir
        - persistentVolumeClaim
        - projected
        - secret

    3. Bind the SecurityContextConstraint object to the Operator’s ServiceAccount by running the following commands:

      $ oc apply -f kmm-security-constraint.yaml
      $ oc adm policy add-scc-to-user kmm-security-constraint -z kmm-operator-controller -n openshift-kmm

    4. Create the following OperatorGroup CR and save the YAML file, for example, kmm-op-group.yaml:

      apiVersion: operators.coreos.com/v1
      kind: OperatorGroup
      metadata:
        name: kernel-module-management
        namespace: openshift-kmm

    5. Create the following Subscription CR and save the YAML file, for example, kmm-sub.yaml:

      apiVersion: operators.coreos.com/v1alpha1
      kind: Subscription
      metadata:
        name: kernel-module-management
        namespace: openshift-kmm
      spec:
        channel: stable
        installPlanApproval: Automatic
        name: kernel-module-management
        source: redhat-operators
        sourceNamespace: openshift-marketplace

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

      $ oc create -f kmm-sub.yaml

Verification

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

    $ oc get -n openshift-kmm deployments.apps kmm-operator-controller

    Example output:

    NAME                              READY UP-TO-DATE  AVAILABLE AGE
    kmm-operator-controller           1/1   1           1         97s

    The Operator is available.

Configuring the Kernel Module Management Operator​

To adapt the Kernel Module Management (KMM) Operator to your OpenShift Container Platform environment, you can create a ConfigMap with custom settings and restart the controller.

Procedure

  • To modify any setting, create a ConfigMap with the name kmm-operator-manager-config in the Operator namespace with the relevant data and restart the controller using the following command:

    $ oc rollout restart -n "$namespace" deployment/kmm-operator-controller

    The value of $namespace depends on your installation method. For example:

    apiVersion: v1
    data:
      controller_config.yaml: |
        worker:
          firmwareHostPath: /example/different/firmware/path
    kind: ConfigMap
    metadata:
      name: kmm-operator-manager-config
      namespace: openshift-kmm
    note

    If you want to configure KMM Hub, create the ConfigMap using the name kmm-operator-hub-manager-config in the KMM Hub controller’s namespace.

    Operator configuration parameters

Parameter Description
healthProbeBindAddress Defines the address on which the Operator monitors for kubelet health probes. The recommended value is :8081.
job.gcDelay Defines the duration for which successful build pods should be preserved before they are deleted. For information about the valid values for this setting, see ParseDuration. The default value is 0s.
leaderElection.enabled Determines whether leader election is used to ensure that only one replica of the KMM Operator is running at any time. For more information, see Leases. The default value is true.
leaderElection.resourceID Determines the name of the resource that leader election uses for holding the leader lock. The default value for KMM is kmm.sigs.x-k8s.io. The default value for KMM-hub is kmm-hub.sigs.x-k8s.io.
metrics.bindAddress Determines the bind address for the metrics server. Set this to "0" to disable the metrics server. The default value is 0.0.0.0:8443.
metrics.disableHTTP2 If true, disables HTTP/2 for the metrics server as a mitigation for CVE-2023-44487. The default value is true.
metrics.enableAuthnAuthz Determines if metrics are authenticated using TokenReviews and authorized using SubjectAccessReviews with the kube-apiserver.

For authentication and authorization, the controller needs a ClusterRole with the following rules:

  • apiGroups: authentication.k8s.io, resources: tokenreviews, verbs: create
  • apiGroups: authorization.k8s.io, resources: subjectaccessreviews, verbs: create
To scrape metrics, for example, using Prometheus, the client needs a ClusterRole with the following rule:

  • nonResourceURLs: "/metrics", verbs: get
The default value is true.
metrics.secureServing Determines whether the metrics are served over HTTPS instead of HTTP. The default value is true.
webhook.disableHTTP2 If true, disables HTTP/2 for the webhook server, as a mitigation for CVE-2023-44487. The default value is true.
webhook.port Defines the port on which the Operator monitors webhook requests. The default value is 9443.
worker.runAsUser Determines the value of the runAsUser field of the worker container's security context. For more information, see SecurityContext. The default value is 9443.
worker.seLinuxType Determines the value of the seLinuxOptions.type field of the worker container's security context. For more information, see SecurityContext. The default value is spc_t.
worker.firmwareHostPath If set, the value of this field is written by the worker container into the /sys/module/firmware_class/parameters/path file on the node. For more information see Setting the kernel's firmware search path. The default value is /var/lib/firmware.

Additional resources

Unloading the kernel module​

To unload a kernel module deployed with KMM on OpenShift Container Platform, you can delete the corresponding Module resource. KMM creates worker pods that run modprobe -r on eligible nodes.

You must unload the kernel modules when moving to a newer version or if they introduce some undesirable side effect on the node.

Procedure

  • To unload a module loaded with KMM from nodes, delete the corresponding Module resource. KMM then creates worker pods, where required, to run modprobe -r and unload the kernel module from the nodes.

    warning

    When unloading worker pods, KMM needs all the resources it uses when loading the kernel module. This includes the ServiceAccount referenced in the Module as well as any RBAC defined to allow privileged KMM worker Pods to run. It also includes any pull secret referenced in .spec.imageRepoSecret.

    To avoid situations where KMM is unable to unload the kernel module from nodes, make sure those resources are not deleted while the Module resource is still present in the cluster in any state, including Terminating. KMM includes a validating admission webhook that rejects the deletion of namespaces that contain at least one Module resource.

Setting the kernel firmware search path​

To configure where KMM worker pods search for firmware on OpenShift Container Platform nodes, you can set the worker.setFirmwareClassPath parameter in the Operator configuration.

The Linux kernel accepts the firmware_class.path parameter as a search path for firmware, as explained in Firmware search paths.

Procedure

  • To define a firmware search path, set worker.setFirmwareClassPath to /var/lib/firmware in the Operator configuration.

Additional resources

Uninstalling the Kernel Module Management Operator​

You can uninstall the Kernel Module Management (KMM) Operator from OpenShift Container Platform by using CLI or uninstalling the Operator.

Uninstalling a Red Hat catalog installation​

To uninstall a Kernel Module Management (KMM) Operator installation from the Red Hat catalog on OpenShift Container Platform, you can remove the Operator from Installed Operators in the web console.

Procedure

  • Use the OpenShift console under Operators --> Installed Operators to locate and uninstall the Operator.

    note

    Alternatively, you can delete the Subscription resource in the KMM namespace.

Uninstalling a CLI installation​

To uninstall a Kernel Module Management (KMM) Operator CLI installation from OpenShift Container Platform, you can run oc delete -k against the upstream configuration manifest.

Procedure

  • Run the following command to uninstall the KMM Operator:

    $ oc delete -k https://github.com/rh-ecosystem-edge/kernel-module-management/config/default
    note

    Using this command deletes the Module CRD and all Module instances in the cluster.

Kernel module deployment​

Kernel Module Management (KMM) monitors Node and Module resources on OpenShift Container Platform to load or unload kernel modules on eligible nodes. KMM creates worker pods on target nodes to reconcile the desired module state.

To be eligible for a module, a node must contain the following:

  • Labels that match the module’s .spec.selector field.
  • A kernel version matching one of the items in the module’s .spec.moduleLoader.container.kernelMappings field.
  • If ordered upgrade (ordered_upgrade.md) is configured in the module, a label that matches its .spec.moduleLoader.container.version field.

When KMM reconciles nodes with the desired state as configured in the Module resource, it creates worker pods on the target nodes to run the necessary action. The KMM Operator monitors the outcome of the pods and records the information. The Operator uses this information to label the Node objects when the module is successfully loaded, and to run the device plugin, if configured.

Worker pods run the KMM worker binary that performs the following tasks:

  • Pulls the kmod image configured in the Module resource. Kmod images are standard OCI images that contain .ko files.
  • Extracts the image in the pod’s filesystem.
  • Runs modprobe with the specified arguments to perform the necessary action.

The Module custom resource definition​

The Module custom resource (CR) in OpenShift Container Platform represents a kernel module that can be loaded on all or select nodes in the cluster, through a kmod image. A Module CR specifies one or more kernel versions with which it is compatible, and a node selector.

The compatible versions for a Module resource are listed under .spec.moduleLoader.container.kernelMappings. A kernel mapping can either match a literal version, or use regexp to match many of them at the same time.

The reconciliation loop for the Module resource runs the following steps:

  1. List all nodes matching .spec.selector.
  2. Build a set of all kernel versions running on those nodes.
  3. For each kernel version:
    1. Go through .spec.moduleLoader.container.kernelMappings and find the appropriate container image name. If the kernel mapping has build or sign defined and the container image does not already exist, run the build, the signing pod, or both, as needed.
    2. Create a worker pod to pull the container image determined in the previous step and run modprobe.
    3. If .spec.devicePlugin is defined, create a device plugin daemon set using the configuration specified under .spec.devicePlugin.container.
  4. Run garbage-collect on:
    1. Obsolete device plugin DaemonSets that do not target any node.
    2. Successful build pods.
    3. Successful signing pods.

Set soft dependencies between kernel modules​

Soft dependencies require kernel modules to load in a specific order even when they do not share symbols. You can declare these dependencies in the Module CR with the modulesLoadingOrder field.

The depmod utility does not recognize soft dependencies, and soft dependencies do not appear in the files it produces. For example, if mod_a has a soft dependency on mod_b, modprobe mod_a will not load mod_b.

# ...
spec:
  moduleLoader:
    container:
      modprobe:
        moduleName: mod_a
        dirName: /opt
        firmwarePath: /firmware
        parameters:
          - param=1
        modulesLoadingOrder:
          - mod_a
          - mod_b

In the configuration above, the worker pod will first try to unload the in-tree mod_b before loading mod_a from the kmod image. When the worker pod is terminated and mod_a is unloaded, mod_b will not be loaded again.

note

The first value in the list, to be loaded last, must be equivalent to the moduleName.

Security and permissions​

KMM security and permissions govern how privileged workloads load kernel modules on OpenShift Container Platform nodes. Review ServiceAccount, SecurityContextConstraint, and pod security requirements before deploying Module resources.

warning

Loading kernel modules is a highly sensitive operation. After they are loaded, kernel modules have all possible permissions to do any kind of operation on the node.

ServiceAccounts and SecurityContextConstraints​

Kernel Module Management (KMM) creates a privileged workload to load the kernel modules on nodes. That workload needs ServiceAccounts allowed to use the privileged SecurityContextConstraint (SCC) resource.

The authorization model for that workload depends on the namespace of the Module resource, as well as its spec.

  • If the .spec.moduleLoader.serviceAccountName or .spec.devicePlugin.serviceAccountName fields are set, they are always used.

  • If those fields are not set, then:

    • If the Module resource is created in the Operator’s namespace (openshift-kmm by default), then KMM uses its default, powerful ServiceAccounts to run the worker and device plugin pods.
    • If the Module resource is created in any other namespace, then KMM runs the pods with the namespace’s default ServiceAccount. The Module resource cannot run a privileged workload unless you manually enable it to use the privileged SCC.
    warning

    openshift-kmm is a trusted namespace.

    When setting up RBAC permissions, remember that any user or ServiceAccount creating a Module resource in the openshift-kmm namespace results in KMM automatically running privileged workloads on potentially all nodes in the cluster.

To allow any ServiceAccount to use the privileged SCC and run worker or device plugin pods, you can use the oc adm policy command, as in the following example:

$ oc adm policy add-scc-to-user privileged -z "${serviceAccountName}" [ -n "${namespace}" ]

Pod security standards​

OpenShift runs a synchronization mechanism that sets the namespace Pod Security level automatically based on the security contexts in use. No action is needed.

Additional resources

Replacing in-tree modules with out-of-tree modules​

You can use Kernel Module Management (KMM) to build kernel modules that can be loaded or unloaded into the kernel on demand. These modules extend the functionality of the kernel without the need to reboot the system. Modules can be configured as built-in or dynamically loaded.

Dynamically loaded modules include in-tree modules and out-of-tree (OOT) modules. In-tree modules are internal to the Linux kernel tree, that is, they are already part of the kernel. Out-of-tree modules are external to the Linux kernel tree. They are generally written for development and testing purposes, such as testing the new version of a kernel module that is shipped in-tree, or to deal with incompatibilities.

Some modules that are loaded by KMM could replace in-tree modules that are already loaded on the node. To unload in-tree modules before loading your module, set the value of the .spec.moduleLoader.container.inTreeModulesToRemove field to the modules that you want to unload. The following example demonstrates module replacement for all kernel mappings:

# ...
spec:
  moduleLoader:
    container:
      modprobe:
        moduleName: mod_a

      inTreeModulesToRemove: [mod_a, mod_b]

In this example, the moduleLoader pod uses inTreeModulesToRemove to unload the in-tree mod_a and mod_b before loading mod_a from the moduleLoader image. When the moduleLoaderpod is terminated and mod_a is unloaded, mod_b is not loaded again.

The following is an example for module replacement for specific kernel mappings:

# ...
spec:
  moduleLoader:
    container:
      kernelMappings:
        - literal: 6.0.15-300.fc37.x86_64
          containerImage: "some.registry/org/my-kmod:${KERNEL_FULL_VERSION}"
          inTreeModulesToRemove: [<module_name>, <module_name>]

Additional resources

Example Module CR​

Use this annotated Module custom resource example as a reference when you configure kernel module loading, device plugins, builds, and signing in OpenShift Container Platform.

apiVersion: kmm.sigs.x-k8s.io/v1beta1
kind: Module
metadata:
  name: <my_kmod>
spec:
  moduleLoader:
    container:
      modprobe:
        moduleName: <my_kmod>
        dirName: /opt
        firmwarePath: /firmware
        parameters:
          - param=1
      kernelMappings:
        - literal: 6.0.15-300.fc37.x86_64
          containerImage: some.registry/org/my-kmod:6.0.15-300.fc37.x86_64
        - regexp: '^.+\fc37\.x86_64$'
          containerImage: "some.other.registry/org/<my_kmod>:${KERNEL_FULL_VERSION}"
        - regexp: '^.+$'
          containerImage: "some.registry/org/<my_kmod>:${KERNEL_FULL_VERSION}"
          build:
            buildArgs:
              - name: ARG_NAME
                value: <some_value>
            secrets:
              - name: <some_kubernetes_secret>
            baseImageRegistryTLS:
              insecure: false
              insecureSkipTLSVerify: false
            dockerfileConfigMap:
              name: <my_kmod_dockerfile>
          sign:
            certSecret:
              name: <cert_secret>
            keySecret:
              name: <key_secret>
            filesToSign:
              - /opt/lib/modules/${KERNEL_FULL_VERSION}/<my_kmod>.ko
          registryTLS:
            insecure: false
            insecureSkipTLSVerify: false
    serviceAccountName: <sa_module_loader>
  devicePlugin:
    container:
      image: some.registry/org/device-plugin:latest
      env:
        - name: MY_DEVICE_PLUGIN_ENV_VAR
          value: SOME_VALUE
      volumeMounts:
        - mountPath: /some/mountPath
          name: <device_plugin_volume>
    volumes:
      - name: <device_plugin_volume>
        configMap:
          name: <some_configmap>
    serviceAccountName: <sa_device_plugin>
  imageRepoSecret:
    name: <secret_name>
  selector:
    node-role.kubernetes.io/worker: ""

where:

spec.moduleLoader.container.modprobe.moduleName
Specifies the name of the module to load. This parameter is required.
spec.moduleLoader.container.modprobe.dirName
Specifies the directory name to use for the module. This parameter is optional.
spec.moduleLoader.container.modprobe.firmwarePath
Specifies the path to the firmware to use for the module. This field is optional. Copies the contents of this path into the path specified in worker.setFirmwareClassPath (which is preset to /var/lib/firmware) of the kmm-operator-manager-config config map. This action occurs before modprobe is called to insert the kernel module.
spec.moduleLoader.container.modprobe.parameters
Specifies the parameters to pass to the module. This parameter is optional.
spec.moduleLoader.container.kernelMappings
Specifies at least one kernel item. This parameter is required.
spec.moduleLoader.container.kernelMappings.regexp
Specifies a tag or digest. Foreach node running a kernel matching the regular expression, KMM checks if you have included a tag or a digest. If you have not specified a tag or digest in the container image, then the validation webhook returns an error and does not apply the module.
spec.moduleLoader.container.kernelMappings.regexp
Specifies that for any other kernel, build the image using the Dockerfile in the my-kmod ConfigMap.
spec.moduleLoader.container.kernelMappings.containerImage
Specifies the container image that holds the customer’s kmods. This container should contain the cp binary.
spec.moduleLoader.container.kernelMappings.build.buildArgs
Specifies an optional field.
spec.moduleLoader.container.kernelMappings.build.secrets
Specifies that a value for some-kubernetes-secret can be obtained from the build environment at /run/secrets/some-kubernetes-secret. This field is optional.
spec.moduleLoader.container.kernelMappings.build.baseImageRegistryTLS
This fied has no effect. When building kmod images or signing kmods within a kmod image, you might sometimes need to pull base images from a registry that serves a certificate signed by an untrusted Certificate Authority (CA). In order for KMM to trust that CA, it must also trust the new CA by replacing the cluster’s CA bundle. See "Replacing the CA Bundle certificate" to learn how to replace the cluster’s CA bundle.
spec.moduleLoader.container.kernelMappings.build.baseImageRegistryTLS.insecureSkipTLSVerify
Specifies to an optional parameter; avoid using it. If set to true, the build skips any TLS server certificate validation when pulling the image in the Dockerfile FROM instruction using plain HTTP. This parameter is optional.
spec.moduleLoader.container.kernelMappings.build.dockerfileConfigMap
Specifies the dockerfileConfigMap parameter. This parameter is required.
spec.moduleLoader.container.kernelMappings.sign.certSecret
Specifies the certSecret parameter. This parameter is required.
spec.moduleLoader.container.kernelMappings.sign.keySecret
Specifies the keySecret parameter. This parameter is required.
spec.moduleLoader.container.kernelMappings.registryTLS
Specifies an optional parameter; avoid using it. If set to true, KMM is allowed to check if the container image already exists using plain HTTP.
spec.moduleLoader.container.kernelMappings.registryTLS.insecure
Specifies a optional parameter; avoid using it. If set to true, KMM skips any TLS server certificate validation when checking if the container image already exists.
spec.moduleLoader.serviceAccountName
Specifies the serviceAccountName parameter. This parameter is optional.
spec.devicePlugin
Specifies the devicePlugin parameter. This parameter is optional.
spec.devicePlugin.container.image
Specifies the image parameter. This parameter is required if the device plugin section is present.
spec.devicePlugin.container.volumeMounts
Specifies the volumeMounts parameter. This parameter is optional.
spec.devicePlugin.volumes
Specifies the volumes parameter. This parameter is optional.
spec.devicePlugin.serviceAccountName
Specifies the serviceAccountName parameter. This parameter is optional.
spec.imageRepoSecret
Specifies the imageRepoSecret parameter. This parameter is used to pull module loader and device plugin images.

Additional resources

Using in-tree modules with the device plugin​

You can configure a KMM Module custom resource on OpenShift Container Platform to use an in-tree kernel module and run only the device plugin. Omit the moduleLoader section and specify only devicePlugin in the CR.

Example Module CR

apiVersion: kmm.sigs.x-k8s.io/v1beta1
kind: Module
metadata:
  name: my-kmod
spec:
  selector:
    node-role.kubernetes.io/worker: ""
  devicePlugin:
    container:
      image: some.registry/org/my-device-plugin:latest

Symbolic links let kmod images reference in-tree kernel module dependencies on OpenShift Container Platform without copying them. KMM mounts /usr/lib/modules so depmod and modprobe can resolve those dependencies at build and runtime.

By creating a symlink from /opt/usr/lib/modules/<kernel_version>/<symlink_name> to /usr/lib/modules/<kernel_version>, depmod can use the in-tree kmods on the building node’s filesystem to resolve dependencies.

At runtime, the worker pod extracts the entire image, including the <symlink_name> symbolic link. That symbolic link points to /usr/lib/modules/<kernel_version> in the worker pod, which is mounted from the node’s filesystem. modprobe can then follow that link and load the in-tree dependencies as needed.

In the following example, host is the symbolic link name under /opt/usr/lib/modules/<kernel_version>:

ARG DTK_AUTO

FROM ${DTK_AUTO} as builder

#
# Build steps
#

FROM ubi9/ubi

ARG KERNEL_FULL_VERSION

RUN dnf update && dnf install -y kmod

COPY --from=builder /usr/src/kernel-module-management/ci/kmm-kmod/kmm_ci_a.ko /opt/lib/modules/${KERNEL_FULL_VERSION}/
COPY --from=builder /usr/src/kernel-module-management/ci/kmm-kmod/kmm_ci_b.ko /opt/lib/modules/${KERNEL_FULL_VERSION}/

# Create the symbolic link
RUN ln -s /lib/modules/${KERNEL_FULL_VERSION} /opt/lib/modules/${KERNEL_FULL_VERSION}/host

RUN depmod -b /opt ${KERNEL_FULL_VERSION}
note

depmod generates dependency files based on the kernel modules present on the node that runs the kmod image build.

On the node on which KMM loads the kernel modules, modprobe expects the files to be present under /usr/lib/modules/<kernel_version>, and the same filesystem layout. It is highly recommended that the build and the target nodes share the same operating system and release.

Creating a kmod image​

A kmod image is a standard OCI container image that holds .ko kernel module files for use with Kernel Module Management (KMM) on OpenShift Container Platform. You must place .ko files under a path that matches <prefix>/lib/modules/[kernel-version]/.

Keep the following in mind when working with the .ko files:

  • In most cases, <prefix> should be equal to /opt. This is the Module CRD’s default value.
  • kernel-version must not be empty and must be equal to the kernel version the kernel modules were built for.

In addition to the .ko files, the kmod image also requires the cp binary to be present because the .ko files are copied from this image to the image-loader worker pod created by the Operator. This is a minimal requirement and no other binary tool is required in the image.

Running depmod​

Run the depmod utlity at the end of the build process to generate modules.dep and .map files. This is especially useful if your kmod image contains several kernel modules and if one of the modules depends on another module.

If you are building your image on OpenShift Container Platform, consider using the Driver Toolkit (DTK). For further information, see How to use entitled image builds to build DriverContainers with UBI on OpenShift.

note

You must have a Red Hat subscription to download the kernel-devel package.

Procedure

  • Generate modules.dep and .map files for a specific kernel version by running the following command:

    $ depmod -b /opt ${KERNEL_FULL_VERSION}+`.

    The following example Dockerfile shows how to run depmod at the end of the build:

    apiVersion: v1
    kind: ConfigMap
    metadata:
      name: kmm-ci-dockerfile
    data:
      dockerfile: |
        ARG DTK_AUTO
        FROM ${DTK_AUTO} as builder
        ARG KERNEL_FULL_VERSION
        WORKDIR /usr/src
        RUN ["git", "clone", "https://github.com/rh-ecosystem-edge/kernel-module-management.git"]
        WORKDIR /usr/src/kernel-module-management/ci/kmm-kmod
        RUN KERNEL_SRC_DIR=/lib/modules/${KERNEL_FULL_VERSION}/build make all
        FROM registry.redhat.io/ubi9/ubi-minimal
        ARG KERNEL_FULL_VERSION
        RUN microdnf install kmod
        COPY --from=builder /usr/src/kernel-module-management/ci/kmm-kmod/kmm_ci_a.ko /opt/lib/modules/${KERNEL_FULL_VERSION}/
        COPY --from=builder /usr/src/kernel-module-management/ci/kmm-kmod/kmm_ci_b.ko /opt/lib/modules/${KERNEL_FULL_VERSION}/
        RUN depmod -b /opt ${KERNEL_FULL_VERSION}

Additional resources

Building in the cluster​

Kernel Module Management (KMM) can build kmod container images in the cluster on OpenShift Container Platform when the image does not already exist in the registry. You configure in-cluster builds through the build section of a kernel mapping in the Module CR.

  • Provide build instructions using the build section of a kernel mapping.
  • Copy the Dockerfile for your container image into a ConfigMap resource, under the dockerfile key.
  • Ensure that the ConfigMap is located in the same namespace as the Module.

KMM checks if the image name specified in the containerImage field exists. If it does, the build is skipped.

Otherwise, KMM creates a Build resource to build your image. After the image is built, KMM proceeds with the Module reconciliation. See the following example.

# ...
- regexp: '^.+$'
  containerImage: "some.registry/org/<my_kmod>:${KERNEL_FULL_VERSION}"
  build:
    buildArgs:
      - name: ARG_NAME
        value: <some_value>
    secrets:
      - name: <some_kubernetes_secret>
    baseImageRegistryTLS:
      insecure: false
      insecureSkipTLSVerify: false
    dockerfileConfigMap:
      name: <my_kmod_dockerfile>
  registryTLS:
    insecure: false
    insecureSkipTLSVerify: false

where:

spec.moduleLoader.container.kernelMappings.build.buildArgs
Specifies build arguments. This field is optional.
spec.moduleLoader.container.kernelMappings.build.secrets
Specifies secrets. This field is optional.
spec.moduleLoader.container.kernelMappings.build.secrets.name
Specifies that the secret will be mounted in the file path of the build pod as /run/secrets/some-kubernetes-secret.
spec.moduleLoader.container.kernelMappings.build.baseImageRegistryTLS.insecure
Specifies an optional parameter; avoid using this parameter. If set to true, the build will be allowed to pull the image in the Dockerfile FROM instruction using plain HTTP.
spec.moduleLoader.container.kernelMappings.build.baseImageRegistryTLS.insecureSkipTLSVerify
Specifies an optional parameter; avoid using this parameter. If set to true, the build will skip any TLS server certificate validation when pulling the image in the Dockerfile FROM instruction using plain HTTP.
spec.moduleLoader.container.kernelMappings.build.dockerfileConfigMap
Specifies the Dockerfile ConfigMap. This field is required.
spec.moduleLoader.container.kernelMappings.registryTLS.insecure
Specifies an optional parameter; avoid using this parameter. If set to true, KMM will be allowed to check if the container image already exists using plain HTTP.
spec.moduleLoader.container.kernelMappings.registryTLS.insecureSkipTLSVerify
Specifies an optional parameter; avoid using this parameter. If set to true, KMM will skip any TLS server certificate validation when checking if the container image already exists.

Successful build pods are garbage collected immediately, unless the job.gcDelay parameter is set in the Operator configuration. Failed build pods are always preserved and must be deleted manually by the administrator for the build to be restarted.

Additional resources

Using the Driver Toolkit​

To build kernel module loader images in OpenShift Container Platform, you can use the Driver Toolkit (DTK) as the first stage of a multi-stage Dockerfile. DTK provides kernel headers and build tools matched to the cluster OpenShift Container Platform version.

Procedure

  1. Build the kernel modules.
  2. Copy the .ko files into a smaller end-user image such as ubi-minimal.
  3. To leverage DTK in your in-cluster build, use the DTK_AUTO build argument. The value is automatically set by KMM when creating the Build resource. See the following example. 
    ARG DTK_AUTO
    FROM ${DTK_AUTO} as builder
    ARG KERNEL_FULL_VERSION
    WORKDIR /usr/src
    RUN ["git", "clone", "https://github.com/rh-ecosystem-edge/kernel-module-management.git"]
    WORKDIR /usr/src/kernel-module-management/ci/kmm-kmod
    RUN KERNEL_SRC_DIR=/lib/modules/${KERNEL_FULL_VERSION}/build make all
    FROM ubi9/ubi-minimal
    ARG KERNEL_FULL_VERSION
    RUN microdnf install kmod
    COPY --from=builder /usr/src/kernel-module-management/ci/kmm-kmod/kmm_ci_a.ko /opt/lib/modules/${KERNEL_FULL_VERSION}/
    COPY --from=builder /usr/src/kernel-module-management/ci/kmm-kmod/kmm_ci_b.ko /opt/lib/modules/${KERNEL_FULL_VERSION}/
    RUN depmod -b /opt ${KERNEL_FULL_VERSION}

Additional resources

Use signing with Kernel Module Management (KMM)​

On Secure Boot-enabled OpenShift Container Platform systems, out-of-tree kernel modules must be signed with keys enrolled in the Machine Owner’s Key (MOK) database. For kernel modules built out of tree, KMM supports signing kmods through the sign section of the kernel mapping in a Module custom resource.

For more details on using Secure Boot, see "Generating a public and private key pair".

Prerequisites​

  • A public private key pair in the correct (DER) format.
  • At least one secure-boot enabled node with the public key enrolled in its MOK database.
  • Either a pre-built driver container image, or the source code and Dockerfile needed to build one in-cluster.

Additional resources

Add the keys for secureboot​

To sign kernel modules with Kernel Module Management (KMM) on OpenShift Container Platform, you can add Secure Boot certificate and private key files as Kubernetes secrets.

For details on how to create these, see Generating a public and private key pair.

For details on how to extract the public and private key pair, see Signing kernel modules with the private key. Use steps 1 through 4 to extract the keys into files.

Procedure

  1. Create the sb_cert.cer file that contains the certificate and the sb_cert.priv file that contains the private key:

    $ openssl req -x509 -new -nodes -utf8 -sha256 -days 36500 -batch -config configuration_file.config -outform DER -out my_signing_key_pub.der -keyout my_signing_key.priv

  2. Add the files by using one of the following methods:

    • Add the files as secrets directly:

      $ oc create secret generic my-signing-key --from-file=key=<my_signing_key.priv>
      $ oc create secret generic my-signing-key-pub --from-file=cert=<my_signing_key_pub.der>

    • Add the files by base64 encoding them:

      $ cat sb_cert.priv | base64 -w 0 > my_signing_key2.base64
      $ cat sb_cert.cer | base64 -w 0 > my_signing_key_pub.base64

  3. Add the encoded text to a YAML file:

    apiVersion: v1
    kind: Secret
    metadata:
      name: my-signing-key-pub
      namespace: default
    type: Opaque
    data:
      cert: <base64_encoded_secureboot_public_key>

    ---
    apiVersion: v1
    kind: Secret
    metadata:
      name: my-signing-key
      namespace: default
    type: Opaque
    data:
      key: <base64_encoded_secureboot_private_key>

    Replace default with a valid namespace.

  4. Apply the YAML file:

    $ oc apply -f <yaml_filename>

Check the keys​

To verify that your secure boot signing keys are configured correctly in OpenShift Container Platform, you can inspect the public certificate and private key secrets with the OpenShift CLI.

Procedure

  1. Check to ensure the public key secret is set correctly:

    $ oc get secret -o yaml <certificate secret name> | awk '/cert/{print $2; exit}' | base64 -d  | openssl x509 -inform der -text

    This should display a certificate with a Serial Number, Issuer, Subject, and more.

  2. Check to ensure the private key secret is set correctly:

    $ oc get secret -o yaml <private key secret name> | awk '/key/{print $2; exit}' | base64 -d

    This should display the key enclosed in the -----BEGIN PRIVATE KEY----- and -----END PRIVATE KEY----- lines.

Sign kmods in a pre-built image​

To sign kernel modules in a vendor-supplied or externally built image on OpenShift Container Platform, you can configure a Module custom resource with unsigned and signed container image references and key secrets.

The following YAML file adds the public/private key-pair as secrets with the required key names - key for the private key, cert for the public key. The cluster then pulls down the unsignedImage image, opens it, signs the kernel modules listed in filesToSign, adds them back, and pushes the resulting image as containerImage.

KMM then loads the signed kmods onto all the nodes with that match the selector. The kmods are successfully loaded on any nodes that have the public key in their MOK database, and any nodes that are not secure-boot enabled, which will ignore the signature.

Prerequisites

  • The keySecret and certSecret secrets have been created in the same namespace as the rest of the resources.

Procedure

  • Apply the YAML file:

    ---
    apiVersion: kmm.sigs.x-k8s.io/v1beta1
    kind: Module
    metadata:
      name: example-module
    spec:
      moduleLoader:
        serviceAccountName: default
        container:
          modprobe:
            moduleName: '<module_name>'
          kernelMappings:
            # the kmods will be deployed on all nodes in the cluster with a kernel that matches the regexp
            - regexp: '^.*\.x86_64$'
              # the container to produce containing the signed kmods
              containerImage: <container_image_name>
              sign:
                # the image containing the unsigned kmods (we need this because we are not building the kmods within the cluster)
                unsignedImage: <unsigned_image_name>
                keySecret: # a secret holding the private secureboot key with the key 'key'
                  name: <private_key_secret_name>
                certSecret: # a secret holding the public secureboot key with the key 'cert'
                  name: <certificate_secret_name>
                filesToSign: # full path within the unsignedImage container to the kmod(s) to sign
                  - /opt/lib/modules/4.18.0-348.2.1.el8_5.x86_64/kmm_ci_a.ko
      imageRepoSecret:
        # the name of a secret containing credentials to pull unsignedImage and push containerImage to the registry
        name: repo-pull-secret
      selector:
        kubernetes.io/arch: amd64

    where:

    <module_name>
    Specifies the name of the kmod to load.
    <container_image_name>
    Specifies the name of the container image. For example, quay.io/myuser/my-driver:<kernelversion.
    <unsigned_image_name>
    Specifies the name of the unsigned image. For example, quay.io/myuser/my-driver:<kernelversion.

Specify files to sign​

You can specify full paths or wildcard and glob patterns to sign kernel module (.ko) files in specific directories.

Kernel Module Management (KMM) provides support for wildcard and glob pattern support for the sign.filesToSign field in the Module CR for signing kernel modules. In addition to using a full path to explicit files, you can use any glob patterns supported by the Bash shell to specify the files to sign.

The DirName value from moduleLoader.container.modprobe is propagated into the sign image. The validation webhook also verifies that all filesToSign entries fall under the configured DirName.

All paths in filesToSign must be under the directory defined by DirName in the same moduleLoader.container.modprobe (default /opt).

The KMM Operator loads the signed kmods onto all of the nodes that match the selector. The kmods should be successfully loaded on any nodes that have the public key in their Machine Owner Key (MOK) database and on any nodes that are not secure-boot enabled (which will just ignore the signature). They should fail to load on any that have secure-boot enabled but do not have that key in their MOK database.

Defining full paths​

You can define one or more absolute paths to kernel module .ko files inside the image.

The following example shows full path usage in the sign.filesToSign field:

sign:
  certSecret:
    name: <cert_secret>
  keySecret:
    name: <key_secret>
  filesToSign:
    - /opt/lib/modules/${KERNEL_FULL_VERSION}/<my-kmod>.ko
    - /opt/lib/modules/${KERNEL_FULL_VERSION}/<my_kmod1>.ko
    - /opt/lib/modules/${KERNEL_FULL_VERSION}/<my_kmod2>.ko

Using wildcard and glob patterns​

You can use wildcard and any glob expression supported by the Ash shell in the sign.filesToSign field. The shell expands each entry at sign time, so you can match multiple modules with a single entry.

  • The following example signs all .ko files in that directory: 
    sign:
      certSecret:
        name: <cert_secret>
      keySecret:
        name: <key_secret>
      filesToSign:
        - /opt/lib/modules/${KERNEL_FULL_VERSION}/*.ko
  • The following example signs all modules matching that pattern, for example, kmm_ci_a.ko, kmm_ci_b.ko, and so on: 
    sign:
      certSecret:
        name: <cert_secret>
      keySecret:
        name: <key_secret>
      filesToSign:
        - /opt/lib/modules/${KERNEL_FULL_VERSION}/kmm_ci_?.ko
  • The following example signs driver-a.ko, driver-b.ko, or driver-c.ko: 
    sign:
      certSecret:
        name: <cert_secret>
      keySecret:
        name: <key_secret>
      filesToSign:
        - /opt/lib/modules/${KERNEL_FULL_VERSION}/driver-[abc].ko
  • The following example signs mod-0.ko through mod-9.ko: 
    sign:
      certSecret:
        name: <cert_secret>
      keySecret:
        name: <key_secret>
      filesToSign:
        - /opt/lib/modules/${KERNEL_FULL_VERSION}/mod-[0-9].ko

Build and sign a kmod image​

To build and sign a kmod image from source code on OpenShift Container Platform, you can apply a Module custom resource that builds an unsigned image and then signs it with your key and certificate secrets.

The following YAML file builds a new container image using the source code from the repository. The image produced is saved back in the registry with a temporary name, and this temporary image is then signed using the parameters in the sign section.

The temporary image name is based on the final image name and is set to be <containerImage>:<tag>-<namespace>_<module name>_kmm_unsigned.

For example, using the following YAML file, Kernel Module Management (KMM) builds an image named example.org/repository/minimal-driver:final-default_example-module_kmm_unsigned containing the build with unsigned kmods and pushes it to the registry. Then it creates a second image named example.org/repository/minimal-driver:final that contains the signed kmods. It is this second image that is pulled by the worker pods and contains the kmods to be loaded on the cluster nodes.

After it is signed, you can safely delete the temporary image from the registry. It will be rebuilt, if needed.

Prerequisites

  • The keySecret and certSecret secrets have been created in the same namespace as the rest of the resources.

Procedure

  • Apply the YAML file:

    ---
    apiVersion: v1
    kind: ConfigMap
    metadata:
      name: example-module-dockerfile
      namespace: <namespace>
    data:
      dockerfile: |
        ARG DTK_AUTO
        ARG KERNEL_VERSION
        FROM ${DTK_AUTO} as builder
        WORKDIR /build/
        RUN git clone -b main --single-branch https://github.com/rh-ecosystem-edge/kernel-module-management.git
        WORKDIR kernel-module-management/ci/kmm-kmod/
        RUN make
        FROM registry.access.redhat.com/ubi9/ubi:latest
        ARG KERNEL_VERSION
        RUN yum -y install kmod && yum clean all
        RUN mkdir -p /opt/lib/modules/${KERNEL_VERSION}
        COPY --from=builder /build/kernel-module-management/ci/kmm-kmod/*.ko /opt/lib/modules/${KERNEL_VERSION}/
        RUN /usr/sbin/depmod -b /opt
    ---
    apiVersion: kmm.sigs.x-k8s.io/v1beta1
    kind: Module
    metadata:
      name: example-module
      namespace: <namespace>
    spec:
      moduleLoader:
        serviceAccountName: default
        container:
          modprobe:
            moduleName: simple_kmod
          kernelMappings:
            - regexp: '^.*\.x86_64$'
              containerImage: <final_driver_container_name>
              build:
                dockerfileConfigMap:
                  name: example-module-dockerfile
              sign:
                keySecret:
                  name: <private_key_secret_name>
                certSecret:
                  name: <certificate_secret_name>
                filesToSign:
                  - /opt/lib/modules/4.18.0-348.2.1.el8_5.x86_64/kmm_ci_a.ko
      imageRepoSecret:
        name: repo-pull-secret
      selector: # top-level selector
        kubernetes.io/arch: amd64

    where:

    metadata.namespace
    Specifies the namespace where the module will be deployed.
    spec.moduleLoader.serviceAccountName
    Specifies the service account that will be used to run the module. The default service account does not have the required permissions to run a module that is privileged. For information on creating a service account, see "Creating service accounts".
    spec.imageRepoSecret
    Specifies that it is used as imagePullSecrets in the DaemonSet object and to pull and push for the build and sign features.

Additional resources

Using tolerations for kernel module scheduling​

You can configure user-defined tolerations in the ModuleSpec resource to ensure Kernel Module Management (KMM) housekeeping pods can run on cordoned or tainted nodes during driver and kernel module upgrades.

When you taint a node to evacuate workload pods prior to an upgrade, setting matching tolerations in the ModuleSpec allows KMM housekeeping pods to deploy and execute driver maintenance without being blocked by node taints.

Applying tolerations to kernel module pods​

Kernel module pods in OpenShift Container Platform can tolerate node taints so KMM schedules them on designated nodes. You can configure toleration parameters in the Module custom resource to match taint effects, keys, and values on target nodes.

Taints and tolerations consist of effect, key, and value parameters. Tolerations include additional operator and tolerationSeconds parameters.

effect
Indicates the taint effect to match. If left empty, all taint effects are matched. When you set effect, valid values are: NoSchedule, PreferNoSchedule, or NoExecute.
key
The taint key that the toleration applies to. If left empty, all taint keys are matched. If the key is empty, you must set the operator parameter to Exists. This combination matches all values and all keys.
value
The taint value the toleration matches to. If the operator parameter is Exists, the value must be empty, otherwise use a regular string.
operator
Represents a relationship of a key to the value. Valid operator parameters are Exists and Equal. The default value is Equal. Exists is equivalent to wildcard for value, so that a pod can tolerate all taints of a particular category.
tolerationSeconds
Represents the period of time the toleration (which must be of effect NoExecute, otherwise this field is ignored) tolerates the taint. By default, it is not set and the taint is tolerated forever without eviction. Zero and negative values are treated as 0 and immediately evicted by the system.

Toleration values must match the taint that is added to the nodes. A toleration matches a taint:

  • If the operator parameter is set to Equal:

    • the key parameters are the same;
    • the value parameters are the same;
    • the effect parameters are the same.

  • If the operator parameter is set to Exists:

    • the key parameters are the same;
    • the effect parameters are the same.

    Example taint in a node specification

    apiVersion: v1
    kind: Node
    metadata:
      name: <my_node>
    #...
    spec:
      taints:
      - effect: NoSchedule
        key: key1
        value: value1
    #...

    Example toleration in a module specification

    apiVersion: kmm.sigs.x-k8s.io/v1beta1
    kind: Module
    metadata:
      name: <my_kmod>
    spec:
      ...
      tolerations:
        effect: NoSchedule
        key: key1
        operator: Equal
        tolerationSeconds: 36000
        value: value1

Additional resources

KMM hub and spoke​

In RHACM hub-and-spoke deployments, the KMM-Hub controller offloads kernel module building and signing to the hub cluster. Administrators can use the ManagedClusterModule custom resource (CR) to load modules on spoke clusters while preserving resources on managed nodes.

In hub and spoke setups, spokes are focused, resource-constrained clusters that are centrally managed by a hub cluster. Spokes run the single-cluster edition of KMM, with those resource-intensive features disabled. To adapt KMM to this environment, you should reduce the workload running on the spokes to the minimum, while the hub takes care of the expensive tasks.

Building kernel module images and signing the .ko files, should run on the hub. The scheduling of the Module Loader and Device Plugin DaemonSets can only happen on the spokes.

Additional resources

KMM-Hub​

KMM-Hub is a hub-cluster edition of Kernel Module Management for OpenShift Container Platform multi-cluster deployments. It monitors spoke kernel versions, runs image builds and kmod signing on the hub, and delivers trimmed Module resources to spokes through RHACM.

note

KMM-Hub cannot be used to load kernel modules on the hub cluster. Install the regular edition of KMM to load kernel modules.

Additional resources

Installing KMM-Hub​

To deploy KMM-Hub for multi-cluster kernel module management on OpenShift Container Platform, you can install it with Operator Lifecycle Manager (OLM) or by creating KMM resources manually.

Additional resources

Installing KMM-Hub using the Operator Lifecycle Manager​

To install KMM-Hub on OpenShift Container Platform using Operator Lifecycle Manager, you can use the Operators section of the OpenShift web console.

Procedure

  • Use the Operators section of the OpenShift console to install KMM-Hub.

Installing KMM-Hub by creating KMM resources​

To install KMM-Hub programmatically on OpenShift Container Platform, you can create Namespace, OperatorGroup, and Subscription resources.

Procedure

  • If you want to install KMM-Hub programmatically, you can use the following resources to create the Namespace, OperatorGroup and Subscription resources: 
    ---
    apiVersion: v1
    kind: Namespace
    metadata:
      name: openshift-kmm-hub
    ---
    apiVersion: operators.coreos.com/v1
    kind: OperatorGroup
    metadata:
      name: kernel-module-management-hub
      namespace: openshift-kmm-hub
    ---
    apiVersion: operators.coreos.com/v1alpha1
    kind: Subscription
    metadata:
      name: kernel-module-management-hub
      namespace: openshift-kmm-hub
    spec:
      channel: stable
      installPlanApproval: Automatic
      name: kernel-module-management-hub
      source: redhat-operators
      sourceNamespace: openshift-marketplace

Using the ManagedClusterModule CRD​

To deploy kernel modules on spoke clusters with KMM-Hub on OpenShift Container Platform, you can configure a cluster-scoped ManagedClusterModule custom resource that wraps a Module spec and selects target clusters.

This CRD is cluster-scoped, wraps a Module spec and adds the following additional fields:

apiVersion: hub.kmm.sigs.x-k8s.io/v1beta1
kind: ManagedClusterModule
metadata:
  name: <my-mcm>
  # No namespace, because this resource is cluster-scoped.
spec:
  moduleSpec:
    selector:
      node-wants-my-mcm: 'true'

  spokeNamespace: <some-namespace>

  selector:
    wants-my-mcm: 'true'

where:

spec.moduleSpec
Specifies the moduleLoader and devicePlugin sections, similar to a Module resource.
spec.moduleSpec.selector
Specifies nodes within the ManagedCluster.
spec.spokeNamespace
Specifies in which namespace the Module should be created.
spec.selector
Specifies ManagedCluster objects.

If build or signing instructions are present in .spec.moduleSpec, those pods are run on the hub cluster in the operator’s namespace.

When the .spec.selector matches one or more ManagedCluster resources, then KMM-Hub creates a ManifestWork resource in the corresponding namespace(s). ManifestWork contains a trimmed-down Module resource, with kernel mappings preserved but all build and sign subsections are removed. containerImage fields that contain image names ending with a tag are replaced with their digest equivalent.

Running KMM on the spoke​

To run Kernel Module Management (KMM) on spoke clusters in OpenShift Container Platform, you can install it with a RHACM Policy object. After installation, create a ManagedClusterModule object from the hub to deploy kernel modules.

You can install KMM on the spokes cluster through a RHACM Policy object. In addition to installing KMM from the software catalog and running it in a lightweight spoke mode, the Policy configures additional RBAC required for the RHACM agent to be able to manage Module resources.

Procedure

  • Use the following RHACM policy to install KMM on spoke clusters:

    ---
    apiVersion: policy.open-cluster-management.io/v1
    kind: Policy
    metadata:
      name: install-kmm
    spec:
      remediationAction: enforce
      disabled: false
      policy-templates:
        - objectDefinition:
            apiVersion: policy.open-cluster-management.io/v1
            kind: ConfigurationPolicy
            metadata:
              name: install-kmm
            spec:
              severity: high
              object-templates:
              - complianceType: mustonlyhave
                objectDefinition:
                  apiVersion: v1
                  kind: Namespace
                  metadata:
                    name: openshift-kmm
              - complianceType: mustonlyhave
                objectDefinition:
                  apiVersion: operators.coreos.com/v1
                  kind: OperatorGroup
                  metadata:
                    name: kmm
                    namespace: openshift-kmm
                  spec:
                    upgradeStrategy: Default
              - complianceType: mustonlyhave
                objectDefinition:
                  apiVersion: operators.coreos.com/v1alpha1
                  kind: Subscription
                  metadata:
                    name: kernel-module-management
                    namespace: openshift-kmm
                  spec:
                    channel: stable
                    config:
                      env:
                        - name: KMM_MANAGED
                          value: "1"
                    installPlanApproval: Automatic
                    name: kernel-module-management
                    source: redhat-operators
                    sourceNamespace: openshift-marketplace
              - complianceType: mustonlyhave
                objectDefinition:
                  apiVersion: rbac.authorization.k8s.io/v1
                  kind: ClusterRole
                  metadata:
                    name: kmm-module-manager
                  rules:
                    - apiGroups: [kmm.sigs.x-k8s.io]
                      resources: [modules]
                      verbs: [create, delete, get, list, patch, update, watch]
              - complianceType: mustonlyhave
                objectDefinition:
                  apiVersion: rbac.authorization.k8s.io/v1
                  kind: ClusterRoleBinding
                  metadata:
                    name: klusterlet-kmm
                  subjects:
                  - kind: ServiceAccount
                    name: klusterlet-work-sa
                    namespace: open-cluster-management-agent
                  roleRef:
                    kind: ClusterRole
                    name: kmm-module-manager
                    apiGroup: rbac.authorization.k8s.io
    ---
    apiVersion: apps.open-cluster-management.io/v1
    kind: PlacementRule
    metadata:
      name: all-managed-clusters
    spec:
      clusterSelector:
        matchExpressions: []
    ---
    apiVersion: policy.open-cluster-management.io/v1
    kind: PlacementBinding
    metadata:
      name: install-kmm
    placementRef:
      apiGroup: apps.open-cluster-management.io
      kind: PlacementRule
      name: all-managed-clusters
    subjects:
      - apiGroup: policy.open-cluster-management.io
        kind: Policy
        name: install-kmm

    where:

    spec.policy-templates.objectDefinition.spec.object-templates.objectDefinition.spec.config.env.name
    Specifies the environment variable name on the Subscription object entry. This variable is required when running KMM on a spoke cluster.
    spec.clusterSelector
    Specifies that on the PlacementRule object entry, this field can be customized to target select clusters only.

Customize upgrades for kernel modules​

The Kernel Module Management (KMM) Operator periodically upgrades Module resources in the cluster, typically during a cluster upgrade.

Use this procedure to upgrade the kernel module while running maintenance operations on the node, including rebooting the node, if needed. To minimize the impact on the workloads running in the cluster, run the kernel upgrade process sequentially, one node at a time.

note

This procedure requires knowledge of the workload using the kernel module and must be managed by the cluster administrator.

Prerequisites

  • Before upgrading, set the kmm.node.kubernetes.io/version-module.<module_namespace>.<module_name>=$moduleVersion label on all the nodes that are used by the kernel module.
  • End all user application workloads on the node or move them to another node.
  • Unload the currently loaded kernel module.
  • Ensure that the user workload (the application running in the cluster that is accessing kernel module) is not running on the node before the kernel module unloads and that the workload is back running on the node after the new kernel module version has been loaded.

Procedure

  1. Ensure that the device plugin managed by KMM on the node is unloaded.

  2. Update the following fields in the Module custom resource (CR):

    • containerImage (to the appropriate kernel version)
    • version The update should be atomic; that is, both the containerImage and version fields must be updated simultaneously.

  3. End any workload using the kernel module on the node being upgraded.

  4. Remove the kmm.node.kubernetes.io/version-module.<module_namespace>.<module_name> label on the node. Run the following command to unload the kernel module from the node:

    $ oc label node/<node_name> kmm.node.kubernetes.io/version-module.<module_namespace>.<module_name>-

  5. If required, as the cluster administrator, perform any additional maintenance required on the node for the kernel module upgrade. If no additional upgrading is needed, you can skip Steps 3 through 6 by updating the kmm.node.kubernetes.io/version-module.<module_namespace>.<module_name> label value to the new $moduleVersion as set in the Module.

  6. Run the following command to add the kmm.node.kubernetes.io/version-module.<module_namespace>.<module_name>=$moduleVersion label to the node. The $moduleVersion must be equal to the new value of the version field in the Module CR.

    $ oc label node/<node_name> kmm.node.kubernetes.io/version-module.<module_namespace>.<module_name>=<desired_version>
    note

    Because of Kubernetes limitations in label names, the combined length of Module name and namespace must not exceed 39 characters.

    The Operator labels the node with a version.ready label to indicate that the new version of the kernel module is loaded and is ready to be used:

    Example output
    `kmm.node.kubernetes.io/<module-namespace>.<module-name>.version.ready=<module-version>`

  7. Restore any workload that leverages the kernel module on the node.

  8. Reload the device plugin managed by KMM on the node.

Day 1 kernel module loading​

Day 1 kernel module loading lets you insert kernel modules during Linux systemd initialization on OpenShift Container Platform, before the standard KMM Day 2 loading and a complete initialization of a Linux (RHCOS) server.

You can use the Machine Config Operator (MCO) when a module must load earlier than full node initialization.

Additional resources

Day 1 supported use cases​

Day 1 supported use cases define when OpenShift Container Platform can load out-of-tree (OOT) kernel modules before NetworkManager starts. This functionality does not support loading modules during the initramfs stage.

The following are the conditions needed for Day 1 functionality:

  • The kernel module is not loaded in the kernel.
  • The in-tree kernel module is loaded into the kernel, but can be unloaded and replaced by the OOT kernel module. This means that the in-tree module is not referenced by any other kernel modules.
  • In order for Day 1 functionlity to work, the node must have a functional network interface, that is, an in-tree kernel driver for that interface. The OOT kernel module can be a network driver that will replace the functional network driver.

OOT kernel module loading flow​

To load an out-of-tree kernel module during OpenShift Container Platform node boot, you can apply a MachineConfig through the Machine Config Operator (MCO). MCO reboots nodes and deploys systemd services that pull the kernel module image and swap in-tree modules for OOT modules.

Procedure

  1. Apply a MachineConfig resource to the existing running cluster. In order to identify the necessary nodes that need to be updated, you must create an appropriate MachineConfigPool resource.
  2. MCO applies the reboots node by node. On any rebooted node, two new systemd services are deployed: pull service and load service.
  3. The load service is configured to run prior to the NetworkConfiguration service. The service tries to pull a predefined kernel module image and then, using that image, to unload an in-tree module and load an OOT kernel module.
  4. The pull service is configured to run after NetworkManager service. The service checks if the preconfigured kernel module image is located on the node’s filesystem. If it is, the service exists normally, and the server continues with the boot process. If not, it pulls the image onto the node and reboots the node afterwards.

The kernel module image​

Day 1 kernel module loading in OpenShift Container Platform uses Driver Toolkit-based container images shared with Day 2 KMM builds. These images must contain your out-of-tree kernel modules so the Machine Config Operator can pull and load them during node boot.

The out-of-tree kernel module should be located under /opt/lib/modules/${kernelVersion}.

Additional resources

In-tree module replacement​

Day 1 kernel module loading in OpenShift Container Platform replaces in-tree kernel modules with out-of-tree (OOT) versions when present. If the in-tree module is not loaded, KMM loads the OOT module without affecting the flow.

MCO yaml creation​

Kernel Module Management (KMM) exposes a ProduceMachineConfig API that generates Machine Config Operator (MCO) YAML for Day 1 out-of-tree kernel module loading on OpenShift Container Platform. You apply the returned manifest to target nodes in a specified MachineConfigPool object.

ProduceMachineConfig(machineConfigName, machineConfigPoolRef, kernelModuleImage, kernelModuleName string) (string, error)

The returned output is a string representation of the MCO YAML manifest to be applied. It is up to the customer to apply this YAML.

The parameters are:

machineConfigName
The name of the MCO YAML manifest. This parameter is set as the name parameter of the metadata of the MCO YAML manifest.
machineConfigPoolRef
The MachineConfigPool name used to identify the targeted nodes.
kernelModuleImage
The name of the container image that includes the OOT kernel module.
kernelModuleName
The name of the OOT kernel module. This parameter is used both to unload the in-tree kernel module (if loaded into the kernel) and to load the OOT kernel module.

The API is located under pkg/mcproducer package of the KMM source code. The KMM operator does not need to be running to use the Day 1 functionality. You only need to import the pkg/mcproducer package into their operator/utility code, call the API, and apply the produced MCO YAML to the cluster.

The MachineConfigPool​

A MachineConfigPool objectidentifies a collection of OpenShift Container Platform nodes affected by Machine Config Operator changes.

kind: MachineConfigPool
metadata:
  name: sfc
spec:
  machineConfigSelector:
    matchExpressions:
      - {key: machineconfiguration.openshift.io/role, operator: In, values: [worker, sfc]}
  nodeSelector:
    matchLabels:
      node-role.kubernetes.io/sfc: ""
  paused: false
  maxUnavailable: 1

where:

spec.machineConfigSelector
Specifies labels that match in the MachineConfig.
spec.nodeSelector
Specifies labels that match on the node.

There are predefined MachineConfigPools in the OCP cluster:

  • worker: Targets all worker nodes in the cluster
  • master: Targets all master nodes in the cluster

Define the following MachineConfig to target the master MachineConfigPool:

metadata:
  labels:
    machineconfiguration.opensfhit.io/role: master

Define the following MachineConfig to target the worker MachineConfigPool:

metadata:
  labels:
    machineconfiguration.opensfhit.io/role: worker

Additional resources

Managing Day 1 kmod images​

Kmod images using the Day 1 utility can be managed by the KMM Operator for full lifecycle management.

In cases where a kmod was installed using the Day 1 utility and a MachineConfig is present in the cluster you can create a Module in the cluster targetting the same kmod and kernel as the MachineConfig. The KMM Operator attempts to load the kmod, but nothing will happen since it is already loaded in the kernel. Future upgrades can be done like Day 2 operations by updating the Module CR in the cluster.

The problem with this approach is if a sudden node reboot occurs, the node is rebooted with the kmod from the MachineConfig and not the kmod from the Module if a kmod upgrade was performed.

Using a BootMachineConfig (BMC) CRD can mitigate this issue. When a Day 1 kmod is transitioned to the KMM Operator using a Module, a BMC needs to be created in the cluster to address the sudden reboot issues by ensuring that the MachineConfig is updated with the correct values without triggering a node reboot.

The following example shows a typical BootMachineConfig CRD:

apiVersion: kmm.sigs.x-k8s.io/v1beta1
 kind: BootModuleConfig
 metadata:
  name: example-bmc
  namespace: openshift-machine-config-operator
 spec:
  machineConfigName: worker-kmod-config
  machineConfigPoolName: worker
  kernelModuleImage: quay.io/example/kmod
  kernelModuleName: my_module
  inTreeModulesToRemove:
    - intree_module_1
    - intree_module_2
  firmwareFilesPath: /firmware
  workerImage: quay.io/<USER>/kernel-module-management-worker:latest
 status:
  conditions: []
machineConfigName
The machineConfig that is targeted by the BMC.
machineConfigPoolName
The machineConfig pool that is linked to the targeted machineConfig.
kernelModuleImage
The kernel module container image that contains the kernel module .ko file without the tag. The pull service determines the kernel version of the node and then uses this value as a tag for the kernel module image. Before upgrading the cluster, all you need to do is to create a kernel module image with the appropriate tag, without any need to update the Day 1 machineConfig. When the node is rebooted, the pull service pulls the correct image.
kernelModuleName
The name of the kernel module to be loaded (the name of the .ko file without the .ko).
inTreeModulesToRemove
An optional list of the in-tree kernel module to remove prior to loading the OOT kernel module.
firmwareFilesPath
An optional path of the firmware files in the kernel module container image.
workerImage
An optional KMM worker image. If not specified, the current worker image is used.

Debugging and troubleshooting​

Unsigned or incorrectly signed kmods in KMM driver containers on OpenShift Container Platform can cause PostStartHookError or CrashLoopBackOff states. You can verify signing issues by running oc describe on the container and checking for a Required key not available error.

The following message appears in this scenario:

modprobe: ERROR: could not insert '<your_kmod_name>': Required key not available

KMM firmware support​

KMM firmware support copying firmware files from the kmod image to a node on OpenShift Container Platform before loading a kernel module.

The contents of .spec.moduleLoader.container.modprobe.firmwarePath are copied into the /var/lib/firmware path on the node before running the modprobe command to insert the kernel module.

All files and empty directories are removed from that location before running the modprobe -r command to unload the kernel module, when the pod is terminated.

Configuring the lookup path on nodes​

To add /var/lib/firmware to the kernel firmware lookup path on OpenShift Container Platform nodes, you can create a MachineConfig custom resource that sets the firmware_class.path kernel argument.

On OpenShift Container Platform nodes, the set of default lookup paths for firmwares does not include the /var/lib/firmware path.

Procedure

  1. Use the Machine Config Operator to create a MachineConfig custom resource (CR) that contains the /var/lib/firmware path:

    apiVersion: machineconfiguration.openshift.io/v1
    kind: MachineConfig
    metadata:
      labels:
        machineconfiguration.openshift.io/role: worker
      name: 99-worker-kernel-args-firmware-path
    spec:
      kernelArguments:
        - 'firmware_class.path=/var/lib/firmware'

    You can configure the label based on your needs. In the case of single-node OpenShift, use either control-pane or master objects.

  2. By applying the MachineConfig CR, the nodes are automatically rebooted.

Additional resources

Building a kmod image​

To build a kmod image with firmware support in OpenShift Container Platform, you can include the binary firmware in the builder image alongside the kernel module.

Procedure

  • In addition to building the kernel module itself, include the binary firmware in the builder image: 
    FROM registry.redhat.io/ubi9/ubi-minimal as builder

    # Build the kmod

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

    FROM registry.redhat.io/ubi9/ubi-minimal

    # Copy the kmod, install modprobe, run depmod

    COPY --from=builder /firmware /firmware

Tuning the Module resource​

To configure firmware file paths for kernel modules on OpenShift Container Platform, you can set .spec.moduleLoader.container.modprobe.firmwarePath in the Module CR.

Procedure

  • Set .spec.moduleLoader.container.modprobe.firmwarePath in the Module custom resource (CR):

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

            firmwarePath: /firmware

    where:

    spec.moduleLoader.container.modprobe.firmwarePath
    Specifies that /firmware/* is copied into the files path /var/lib/firmware/ on the node. This parameter is optional.

Day 0 through Day 2 kmod installation​

You can install some kernel modules (kmods) during Day 0 through Day 2 operations without Kernel Module Management (KMM). You can use these stages to plan kmod transitions to KMM.

Use the following criteria to determine suitable kmod installations.

Day 0
The most basic kmods that are required for a node to become Ready in the cluster. Examples of these types of kmods include:
  • A storage driver that is required to mount the rootFS as part of the boot process
  • A network driver that is required for the machine to access machine-config-server on the bootstrap node to pull the ignition and join the cluster
Day 1
Kmods that are not required for a node to become Ready in the cluster but cannot be unloaded when the node is Ready. An example of this type of kmod is an out-of-tree (OOT) network driver that replaces an outdated in-tree driver to exploit the full potential of the NIC while NetworkManager depends on it. When the node is Ready, you cannot unload the driver because of the NetworkManager dependency.
Day 2
Kmods that can be dynamically loaded to the kernel or removed from it without interfering with the cluster infrastructure, for example, connectivity. Examples of these types of kmods include:
  • GPU operators
  • Secondary network adapters
  • field-programmable gate arrays (FPGAs)

Layering background​

Layering applies Day 0 kernel modules through the Machine Config Operator (MCO) on OpenShift Container Platform, so cluster upgrades do not trigger node upgrades for those modules. You recompile the driver only when you add new features, because the node operating system stays the same.

Lifecycle management​

KMM lifecycle management on OpenShift Container Platform lets you upgrade kmods from Day 0 through Day 2 without rebooting nodes when the driver supports it.

note

This will not work if the upgrade requires a node reboot, for example, when rebuilding initramfs files is needed.

Use one of the following options for lifecycle management.

Treat the kmod as an in-tree driver​

Use this method when you want to upgrade the kmods. In this case, treat the kmod as an in-tree driver and create a Module in the cluster with the inTreeRemoval field to unload the old version of the driver.

Note the following characteristics of treating the kmod as an in-tree driver:

  • Downtime might occur as KMM tries to unload and load the kmod on all the selected nodes simultaneously.
  • This works if removing the driver makes the node lose connectivity because KMM uses a single pod to unload and load the driver.

Use ordered upgrade​

You can use ordered upgrade (ordered_upgrade.md) to create a versioned Module in the cluster representing the kmods with no effect, because the kmods are already loaded.

Note the following characteristics of using ordered upgrade:

  • There is no cluster downtime because you control the pace of the upgrade and how many nodes are upgraded at the same time; therefore, an upgrade with no downtime is possible.
  • This method will not work if unloading the driver results in losing connection to the node, because KMM creates two different worker pods for unloading and another for loading. These pods will not be scheduled.

Troubleshooting KMM​

When troubleshooting KMM on OpenShift Container Platform, you can monitor Operator logs to identify the failure stage and gather diagnostic data for that stage.

Reading Operator logs​

KMM and KMM-Hub Operator logs on OpenShift Container Platform provide diagnostic information for troubleshooting installation and runtime issues. You can read them with the oc logs command against the controller and webhook server deployments.

Example command for KMM controller
$ oc logs -fn openshift-kmm deployments/kmm-operator-controller
Example command for KMM webhook server
$ oc logs -fn openshift-kmm deployments/kmm-operator-webhook-server
Example command for KMM-Hub controller
$ oc logs -fn openshift-kmm-hub deployments/kmm-operator-hub-controller
Example command for KMM-Hub webhook server
$ oc logs -fn openshift-kmm deployments/kmm-operator-hub-webhook-server

Observing events​

You can observe Kernel Module Management (KMM) events on OpenShift Container Platform to monitor kmod image builds, signing, and module load or unload operations. Events attach to Module and Node objects and appear in oc describe output.

Build & sign​

KMM publishes events whenever it starts a kmod image build or observes its outcome. These events are attached to Module objects and are available at the end of the output of oc describe module command, as in the following example:

$ oc describe modules.kmm.sigs.x-k8s.io kmm-ci-a
[...]
Events:
  Type    Reason          Age                From  Message
  ----    ------          ----               ----  -------
  Normal  BuildCreated    2m29s              kmm   Build created for kernel 6.6.2-201.fc39.x86_64
  Normal  BuildSucceeded  63s                kmm   Build job succeeded for kernel 6.6.2-201.fc39.x86_64
  Normal  SignCreated     64s (x2 over 64s)  kmm   Sign created for kernel 6.6.2-201.fc39.x86_64
  Normal  SignSucceeded   57s                kmm   Sign job succeeded for kernel 6.6.2-201.fc39.x86_64

Module load or unload​

KMM publishes events whenever it successfully loads or unloads a kernel module on a node. These events are attached to Node objects and are available at the end of the output of oc describe node command, as in the following example:

$ oc describe node my-node
[...]
Events:
  Type    Reason          Age    From  Message
  ----    ------          ----   ----  -------
[...]
  Normal  ModuleLoaded    4m17s  kmm   Module default/kmm-ci-a loaded into the kernel
  Normal  ModuleUnloaded  2s     kmm   Module default/kmm-ci-a unloaded from the kernel

Using the must-gather tool​

To collect Kernel Module Management debugging data for Red Hat Support on OpenShift Container Platform, you can run the oc adm must-gather command with KMM-specific arguments.

Additional resources

Gathering data for KMM​

To troubleshoot Kernel Module Management (KMM) on OpenShift Container Platform, you can gather Operator data with the must-gather tool and review controller manager logs.

Procedure

  1. Gather the data for the KMM Operator controller manager:

    1. Set the MUST_GATHER_IMAGE variable:

      $ export MUST_GATHER_IMAGE=$(oc get deployment -n openshift-kmm kmm-operator-controller -ojsonpath='{.spec.template.spec.containers[?(@.name=="manager")].env[?(@.name=="RELATED_IMAGE_MUST_GATHER")].value}')
      $ oc adm must-gather --image="${MUST_GATHER_IMAGE}" -- /usr/bin/gather
      note

      Use the -n <namespace> switch to specify a namespace if you installed KMM in a custom namespace.

    2. Run the must-gather tool:

      $ oc adm must-gather --image="${MUST_GATHER_IMAGE}" -- /usr/bin/gather

  2. View the Operator logs:

    $ oc logs -fn openshift-kmm deployments/kmm-operator-controller

    Example output:

    I0228 09:36:37.352405       1 request.go:682] Waited for 1.001998746s due to client-side throttling, not priority and fairness, request: GET:https://172.30.0.1:443/apis/machine.openshift.io/v1beta1?timeout=32s
    I0228 09:36:40.767060       1 listener.go:44] kmm/controller-runtime/metrics "msg"="Metrics server is starting to listen" "addr"="127.0.0.1:8080"
    I0228 09:36:40.769483       1 main.go:234] kmm/setup "msg"="starting manager"
    I0228 09:36:40.769907       1 internal.go:366] kmm "msg"="Starting server" "addr"={"IP":"127.0.0.1","Port":8080,"Zone":""} "kind"="metrics" "path"="/metrics"
    I0228 09:36:40.770025       1 internal.go:366] kmm "msg"="Starting server" "addr"={"IP":"::","Port":8081,"Zone":""} "kind"="health probe"
    I0228 09:36:40.770128       1 leaderelection.go:248] attempting to acquire leader lease openshift-kmm/kmm.sigs.x-k8s.io...
    I0228 09:36:40.784396       1 leaderelection.go:258] successfully acquired lease openshift-kmm/kmm.sigs.x-k8s.io
    I0228 09:36:40.784876       1 controller.go:185] kmm "msg"="Starting EventSource" "controller"="Module" "controllerGroup"="kmm.sigs.x-k8s.io" "controllerKind"="Module" "source"="kind source: *v1beta1.Module"
    I0228 09:36:40.784925       1 controller.go:185] kmm "msg"="Starting EventSource" "controller"="Module" "controllerGroup"="kmm.sigs.x-k8s.io" "controllerKind"="Module" "source"="kind source: *v1.DaemonSet"
    I0228 09:36:40.784968       1 controller.go:185] kmm "msg"="Starting EventSource" "controller"="Module" "controllerGroup"="kmm.sigs.x-k8s.io" "controllerKind"="Module" "source"="kind source: *v1.Build"
    I0228 09:36:40.785001       1 controller.go:185] kmm "msg"="Starting EventSource" "controller"="Module" "controllerGroup"="kmm.sigs.x-k8s.io" "controllerKind"="Module" "source"="kind source: *v1.Job"
    I0228 09:36:40.785025       1 controller.go:185] kmm "msg"="Starting EventSource" "controller"="Module" "controllerGroup"="kmm.sigs.x-k8s.io" "controllerKind"="Module" "source"="kind source: *v1.Node"
    I0228 09:36:40.785039       1 controller.go:193] kmm "msg"="Starting Controller" "controller"="Module" "controllerGroup"="kmm.sigs.x-k8s.io" "controllerKind"="Module"
    I0228 09:36:40.785458       1 controller.go:185] kmm "msg"="Starting EventSource" "controller"="PodNodeModule" "controllerGroup"="" "controllerKind"="Pod" "source"="kind source: *v1.Pod"
    I0228 09:36:40.786947       1 controller.go:185] kmm "msg"="Starting EventSource" "controller"="PreflightValidation" "controllerGroup"="kmm.sigs.x-k8s.io" "controllerKind"="PreflightValidation" "source"="kind source: *v1beta1.PreflightValidation"
    I0228 09:36:40.787406       1 controller.go:185] kmm "msg"="Starting EventSource" "controller"="PreflightValidation" "controllerGroup"="kmm.sigs.x-k8s.io" "controllerKind"="PreflightValidation" "source"="kind source: *v1.Build"
    I0228 09:36:40.787474       1 controller.go:185] kmm "msg"="Starting EventSource" "controller"="PreflightValidation" "controllerGroup"="kmm.sigs.x-k8s.io" "controllerKind"="PreflightValidation" "source"="kind source: *v1.Job"
    I0228 09:36:40.787488       1 controller.go:185] kmm "msg"="Starting EventSource" "controller"="PreflightValidation" "controllerGroup"="kmm.sigs.x-k8s.io" "controllerKind"="PreflightValidation" "source"="kind source: *v1beta1.Module"
    I0228 09:36:40.787603       1 controller.go:185] kmm "msg"="Starting EventSource" "controller"="NodeKernel" "controllerGroup"="" "controllerKind"="Node" "source"="kind source: *v1.Node"
    I0228 09:36:40.787634       1 controller.go:193] kmm "msg"="Starting Controller" "controller"="NodeKernel" "controllerGroup"="" "controllerKind"="Node"
    I0228 09:36:40.787680       1 controller.go:193] kmm "msg"="Starting Controller" "controller"="PreflightValidation" "controllerGroup"="kmm.sigs.x-k8s.io" "controllerKind"="PreflightValidation"
    I0228 09:36:40.785607       1 controller.go:185] kmm "msg"="Starting EventSource" "controller"="imagestream" "controllerGroup"="image.openshift.io" "controllerKind"="ImageStream" "source"="kind source: *v1.ImageStream"
    I0228 09:36:40.787822       1 controller.go:185] kmm "msg"="Starting EventSource" "controller"="preflightvalidationocp" "controllerGroup"="kmm.sigs.x-k8s.io" "controllerKind"="PreflightValidationOCP" "source"="kind source: *v1beta1.PreflightValidationOCP"
    I0228 09:36:40.787853       1 controller.go:193] kmm "msg"="Starting Controller" "controller"="imagestream" "controllerGroup"="image.openshift.io" "controllerKind"="ImageStream"
    I0228 09:36:40.787879       1 controller.go:185] kmm "msg"="Starting EventSource" "controller"="preflightvalidationocp" "controllerGroup"="kmm.sigs.x-k8s.io" "controllerKind"="PreflightValidationOCP" "source"="kind source: *v1beta1.PreflightValidation"
    I0228 09:36:40.787905       1 controller.go:193] kmm "msg"="Starting Controller" "controller"="preflightvalidationocp" "controllerGroup"="kmm.sigs.x-k8s.io" "controllerKind"="PreflightValidationOCP"
    I0228 09:36:40.786489       1 controller.go:193] kmm "msg"="Starting Controller" "controller"="PodNodeModule" "controllerGroup"="" "controllerKind"="Pod"

Gathering data for KMM-Hub​

To collect diagnostic data for the KMM-Hub Operator on OpenShift Container Platform, you can run the must-gather tool with the hub controller image and review Operator logs.

Procedure

  1. Gather the data for the KMM Operator hub controller manager:

    1. Set the MUST_GATHER_IMAGE variable:

      $ export MUST_GATHER_IMAGE=$(oc get deployment -n openshift-kmm-hub kmm-operator-hub-controller -ojsonpath='{.spec.template.spec.containers[?(@.name=="manager")].env[?(@.name=="RELATED_IMAGE_MUST_GATHER")].value}')
      $ oc adm must-gather --image="${MUST_GATHER_IMAGE}" -- /usr/bin/gather -u
      note

      Use the -n <namespace> switch to specify a namespace if you installed KMM in a custom namespace.

    2. Run the must-gather tool:

      $ oc adm must-gather --image="${MUST_GATHER_IMAGE}" -- /usr/bin/gather -u

  2. View the Operator logs:

    $ oc logs -fn openshift-kmm-hub deployments/kmm-operator-hub-controller

    Example output:

    I0417 11:34:08.807472       1 request.go:682] Waited for 1.023403273s due to client-side throttling, not priority and fairness, request: GET:https://172.30.0.1:443/apis/tuned.openshift.io/v1?timeout=32s
    I0417 11:34:12.373413       1 listener.go:44] kmm-hub/controller-runtime/metrics "msg"="Metrics server is starting to listen" "addr"="127.0.0.1:8080"
    I0417 11:34:12.376253       1 main.go:150] kmm-hub/setup "msg"="Adding controller" "name"="ManagedClusterModule"
    I0417 11:34:12.376621       1 main.go:186] kmm-hub/setup "msg"="starting manager"
    I0417 11:34:12.377690       1 leaderelection.go:248] attempting to acquire leader lease openshift-kmm-hub/kmm-hub.sigs.x-k8s.io...
    I0417 11:34:12.378078       1 internal.go:366] kmm-hub "msg"="Starting server" "addr"={"IP":"127.0.0.1","Port":8080,"Zone":""} "kind"="metrics" "path"="/metrics"
    I0417 11:34:12.378222       1 internal.go:366] kmm-hub "msg"="Starting server" "addr"={"IP":"::","Port":8081,"Zone":""} "kind"="health probe"
    I0417 11:34:12.395703       1 leaderelection.go:258] successfully acquired lease openshift-kmm-hub/kmm-hub.sigs.x-k8s.io
    I0417 11:34:12.396334       1 controller.go:185] kmm-hub "msg"="Starting EventSource" "controller"="ManagedClusterModule" "controllerGroup"="hub.kmm.sigs.x-k8s.io" "controllerKind"="ManagedClusterModule" "source"="kind source: *v1beta1.ManagedClusterModule"
    I0417 11:34:12.396403       1 controller.go:185] kmm-hub "msg"="Starting EventSource" "controller"="ManagedClusterModule" "controllerGroup"="hub.kmm.sigs.x-k8s.io" "controllerKind"="ManagedClusterModule" "source"="kind source: *v1.ManifestWork"
    I0417 11:34:12.396430       1 controller.go:185] kmm-hub "msg"="Starting EventSource" "controller"="ManagedClusterModule" "controllerGroup"="hub.kmm.sigs.x-k8s.io" "controllerKind"="ManagedClusterModule" "source"="kind source: *v1.Build"
    I0417 11:34:12.396469       1 controller.go:185] kmm-hub "msg"="Starting EventSource" "controller"="ManagedClusterModule" "controllerGroup"="hub.kmm.sigs.x-k8s.io" "controllerKind"="ManagedClusterModule" "source"="kind source: *v1.Job"
    I0417 11:34:12.396522       1 controller.go:185] kmm-hub "msg"="Starting EventSource" "controller"="ManagedClusterModule" "controllerGroup"="hub.kmm.sigs.x-k8s.io" "controllerKind"="ManagedClusterModule" "source"="kind source: *v1.ManagedCluster"
    I0417 11:34:12.396543       1 controller.go:193] kmm-hub "msg"="Starting Controller" "controller"="ManagedClusterModule" "controllerGroup"="hub.kmm.sigs.x-k8s.io" "controllerKind"="ManagedClusterModule"
    I0417 11:34:12.397175       1 controller.go:185] kmm-hub "msg"="Starting EventSource" "controller"="imagestream" "controllerGroup"="image.openshift.io" "controllerKind"="ImageStream" "source"="kind source: *v1.ImageStream"
    I0417 11:34:12.397221       1 controller.go:193] kmm-hub "msg"="Starting Controller" "controller"="imagestream" "controllerGroup"="image.openshift.io" "controllerKind"="ImageStream"
    I0417 11:34:12.498335       1 filter.go:196] kmm-hub "msg"="Listing all ManagedClusterModules" "managedcluster"="local-cluster"
    I0417 11:34:12.498570       1 filter.go:205] kmm-hub "msg"="Listed ManagedClusterModules" "count"=0 "managedcluster"="local-cluster"
    I0417 11:34:12.498629       1 filter.go:238] kmm-hub "msg"="Adding reconciliation requests" "count"=0 "managedcluster"="local-cluster"
    I0417 11:34:12.498687       1 filter.go:196] kmm-hub "msg"="Listing all ManagedClusterModules" "managedcluster"="sno1-0"
    I0417 11:34:12.498750       1 filter.go:205] kmm-hub "msg"="Listed ManagedClusterModules" "count"=0 "managedcluster"="sno1-0"
    I0417 11:34:12.498801       1 filter.go:238] kmm-hub "msg"="Adding reconciliation requests" "count"=0 "managedcluster"="sno1-0"
    I0417 11:34:12.501947       1 controller.go:227] kmm-hub "msg"="Starting workers" "controller"="imagestream" "controllerGroup"="image.openshift.io" "controllerKind"="ImageStream" "worker count"=1
    I0417 11:34:12.501948       1 controller.go:227] kmm-hub "msg"="Starting workers" "controller"="ManagedClusterModule" "controllerGroup"="hub.kmm.sigs.x-k8s.io" "controllerKind"="ManagedClusterModule" "worker count"=1
    I0417 11:34:12.502285       1 imagestream_reconciler.go:50] kmm-hub "msg"="registered imagestream info mapping" "ImageStream"={"name":"driver-toolkit","namespace":"openshift"} "controller"="imagestream" "controllerGroup"="image.openshift.io" "controllerKind"="ImageStream" "dtkImage"="quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:df42b4785a7a662b30da53bdb0d206120cf4d24b45674227b16051ba4b7c3934" "name"="driver-toolkit" "namespace"="openshift" "osImageVersion"="412.86.202302211547-0" "reconcileID"="e709ff0a-5664-4007-8270-49b5dff8bae9"