Configuring the SR-IOV Operator - Hardware networks | Networking

Configuring the SR-IOV Network Operator
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The Single Root I/O Virtualization (SR-IOV) Network Operator manages the SR-IOV network devices and network attachments in your cluster.

Configuring the SR-IOV Network Operator

Modifying the SR-IOV Network Operator configuration is not normally necessary. The default configuration is recommended for most use cases. Complete the steps to modify the relevant configuration only if the default behavior of the Operator is not compatible with your use case.

The SR-IOV Network Operator adds the SriovOperatorConfig.sriovnetwork.openshift.io CustomResourceDefinition resource. The Operator automatically creates a SriovOperatorConfig custom resource (CR) named default in the openshift-sriov-network-operator namespace.

The default CR contains the SR-IOV Network Operator configuration for your cluster. To change the Operator configuration, you must modify this CR.

SR-IOV Network Operator config custom resource

The fields for the sriovoperatorconfig custom resource are described in the following table:

Table 1. SR-IOV Network Operator config custom resource
Field	Type	Description
`metadata.name`	`string`	Specifies the name of the SR-IOV Network Operator instance. The default value is `default`. Do not set a different value.
`metadata.namespace`	`string`	Specifies the namespace of the SR-IOV Network Operator instance. The default value is `openshift-sriov-network-operator`. Do not set a different value.
`spec.configDaemonNodeSelector`	`string`	Specifies the node selection to control scheduling the SR-IOV Network Config Daemon on selected nodes. By default, this field is not set and the Operator deploys the SR-IOV Network Config daemon set on worker nodes.
`spec.disableDrain`	`boolean`	Specifies whether to disable the node draining process or enable the node draining process when you apply a new policy to configure the NIC on a node. Setting this field to `true` facilitates software development and installing OKD on a single node. By default, this field is not set. For single-node clusters, set this field to `true` after installing the Operator. This field must remain set to `true`.
`spec.enableInjector`	`boolean`	Specifies whether to enable or disable the Network Resources Injector daemon set. By default, this field is set to `true`.
`spec.enableOperatorWebhook`	`boolean`	Specifies whether to enable or disable the Operator Admission Controller webhook daemon set. By default, this field is set to `true`.
`spec.logLevel`	`integer`	Specifies the log verbosity level of the Operator. Set to `0` to show only the basic logs. Set to `2` to show all the available logs. By default, this field is set to `2`.

About the Network Resources Injector

The Network Resources Injector is a Kubernetes Dynamic Admission Controller application. It provides the following capabilities:

Mutation of resource requests and limits in a pod specification to add an SR-IOV resource name according to an SR-IOV network attachment definition annotation.
Mutation of a pod specification with a Downward API volume to expose pod annotations, labels, and huge pages requests and limits. Containers that run in the pod can access the exposed information as files under the /etc/podnetinfo path.

By default, the Network Resources Injector is enabled by the SR-IOV Network Operator and runs as a daemon set on all control plane nodes. The following is an example of Network Resources Injector pods running in a cluster with three control plane nodes:

$ oc get pods -n openshift-sriov-network-operator

Example output

NAME                                      READY   STATUS    RESTARTS   AGE
network-resources-injector-5cz5p          1/1     Running   0          10m
network-resources-injector-dwqpx          1/1     Running   0          10m
network-resources-injector-lktz5          1/1     Running   0          10m

About the SR-IOV Network Operator admission controller webhook

The SR-IOV Network Operator Admission Controller webhook is a Kubernetes Dynamic Admission Controller application. It provides the following capabilities:

Validation of the SriovNetworkNodePolicy CR when it is created or updated.
Mutation of the SriovNetworkNodePolicy CR by setting the default value for the priority and deviceType fields when the CR is created or updated.

By default the SR-IOV Network Operator Admission Controller webhook is enabled by the Operator and runs as a daemon set on all control plane nodes.

Use caution when disabling the SR-IOV Network Operator Admission Controller webhook. You can disable the webhook under specific circumstances, such as troubleshooting, or if you want to use unsupported devices.

The following is an example of the Operator Admission Controller webhook pods running in a cluster with three control plane nodes:

$ oc get pods -n openshift-sriov-network-operator

Example output

NAME                                      READY   STATUS    RESTARTS   AGE
operator-webhook-9jkw6                    1/1     Running   0          16m
operator-webhook-kbr5p                    1/1     Running   0          16m
operator-webhook-rpfrl                    1/1     Running   0          16m

About custom node selectors

The SR-IOV Network Config daemon discovers and configures the SR-IOV network devices on cluster nodes. By default, it is deployed to all the worker nodes in the cluster. You can use node labels to specify on which nodes the SR-IOV Network Config daemon runs.

Disabling or enabling the Network Resources Injector

To disable or enable the Network Resources Injector, which is enabled by default, complete the following procedure.

Prerequisites

Install the OpenShift CLI (oc).
Log in as a user with cluster-admin privileges.
You must have installed the SR-IOV Network Operator.

Procedure

Set the enableInjector field. Replace <value> with false to disable the feature or true to enable the feature.

$ oc patch sriovoperatorconfig default \
  --type=merge -n openshift-sriov-network-operator \
  --patch '{ "spec": { "enableInjector": <value> } }'

You can alternatively apply the following YAML to update the Operator:

apiVersion: sriovnetwork.openshift.io/v1
kind: SriovOperatorConfig
metadata:
  name: default
  namespace: openshift-sriov-network-operator
spec:
  enableInjector: <value>

Disabling or enabling the SR-IOV Network Operator admission controller webhook

To disable or enable the admission controller webhook, which is enabled by default, complete the following procedure.

Prerequisites

Install the OpenShift CLI (oc).
Log in as a user with cluster-admin privileges.
You must have installed the SR-IOV Network Operator.

Procedure

Set the enableOperatorWebhook field. Replace <value> with false to disable the feature or true to enable it:

$ oc patch sriovoperatorconfig default --type=merge \
  -n openshift-sriov-network-operator \
  --patch '{ "spec": { "enableOperatorWebhook": <value> } }'

You can alternatively apply the following YAML to update the Operator:

apiVersion: sriovnetwork.openshift.io/v1
kind: SriovOperatorConfig
metadata:
  name: default
  namespace: openshift-sriov-network-operator
spec:
  enableOperatorWebhook: <value>

Configuring a custom NodeSelector for the SR-IOV Network Config daemon

To specify the nodes where the SR-IOV Network Config daemon is deployed, complete the following procedure.

When you update the configDaemonNodeSelector field, the SR-IOV Network Config daemon is recreated on each selected node. While the daemon is recreated, cluster users are unable to apply any new SR-IOV Network node policy or create new SR-IOV pods.

Procedure

To update the node selector for the operator, enter the following command:

$ oc patch sriovoperatorconfig default --type=json \
  -n openshift-sriov-network-operator \
  --patch '[{
      "op": "replace",
      "path": "/spec/configDaemonNodeSelector",
      "value": {<node_label>}
    }]'

Replace <node_label> with a label to apply as in the following example: "node-role.kubernetes.io/worker": "".

You can alternatively apply the following YAML to update the Operator:

apiVersion: sriovnetwork.openshift.io/v1
kind: SriovOperatorConfig
metadata:
  name: default
  namespace: openshift-sriov-network-operator
spec:
  configDaemonNodeSelector:
    <node_label>

Configuring the SR-IOV Network Operator for single node installations

By default, the SR-IOV Network Operator drains workloads from a node before every policy change. The Operator performs this action to ensure that there no workloads using the virtual functions before the reconfiguration.

For installations on a single node, there are no other nodes to receive the workloads. As a result, the Operator must be configured not to drain the workloads from the single node.

After performing the following procedure to disable draining workloads, you must remove any workload that uses an SR-IOV network interface before you change any SR-IOV network node policy.

Prerequisites

Install the OpenShift CLI (oc).
Log in as a user with cluster-admin privileges.
You must have installed the SR-IOV Network Operator.

Procedure

To set the disableDrain field to true, enter the following command:

$ oc patch sriovoperatorconfig default --type=merge \
  -n openshift-sriov-network-operator \
  --patch '{ "spec": { "disableDrain": true } }'

You can alternatively apply the following YAML to update the Operator:

apiVersion: sriovnetwork.openshift.io/v1
kind: SriovOperatorConfig
metadata:
  name: default
  namespace: openshift-sriov-network-operator
spec:
  disableDrain: true

Next steps

Configuring an SR-IOV network device