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Kubernetes NMState Operator

The Kubernetes NMState Operator provides a Kubernetes API for performing state-driven network configuration across the OpenShift Container Platform cluster’s nodes with NMState. The Kubernetes NMState Operator provides users with functionality to configure various network interface types, DNS, and routing on cluster nodes. Additionally, the daemons on the cluster nodes periodically report on the state of each node’s network interfaces to the API server.

Red Hat supports the Kubernetes NMState Operator in production environments on bare-metal, IBM Power®, IBM Z®, IBM® LinuxONE, VMware vSphere, and Red Hat OpenStack Platform (RHOSP) installations.

Red Hat support exists for using the Kubernetes NMState Operator on Microsoft Azure but in a limited capacity. Support is limited to configuring DNS servers on your system as a postinstallation task.

Before you can use NMState with OpenShift Container Platform, you must install the Kubernetes NMState Operator.

The Kubernetes NMState Operator updates the network configuration of a secondary NIC. The Operator cannot update the network configuration of the primary NIC, or update the br-ex bridge on most on-premise networks.

On a bare-metal platform, using the Kubernetes NMState Operator to update the br-ex bridge network configuration is only supported if you set the br-ex bridge as the interface in a machine config manifest file. To update the br-ex bridge as a postinstallation task, you must set the br-ex bridge as the interface in the NMState configuration of the NodeNetworkConfigurationPolicy custom resource (CR) for your cluster. For more information, see Creating a manifest object that includes a customized br-ex bridge in Postinstallation configuration.

OpenShift Container Platform uses nmstate to report on and configure the state of the node network. This makes it possible to modify the network policy configuration, such as by creating a Linux bridge on all nodes, by applying a single configuration manifest to the cluster.

Node networking is monitored and updated by the following objects:

NodeNetworkState

Reports the state of the network on that node.

NodeNetworkConfigurationPolicy

Describes the requested network configuration on nodes. You update the node network configuration, including adding and removing interfaces, by applying a NodeNetworkConfigurationPolicy CR to the cluster.

NodeNetworkConfigurationEnactment

Reports the network policies enacted upon each node.

Installing the Kubernetes NMState Operator

You can install the Kubernetes NMState Operator by using the web console or the CLI.

Installing the Kubernetes NMState Operator by using the web console

You can install the Kubernetes NMState Operator by using the web console. After it is installed, the Operator can deploy the NMState State Controller as a daemon set across all of the cluster nodes.

Prerequisites

  • You are logged in as a user with cluster-admin privileges.

Procedure

  1. Select Operators → OperatorHub.

  2. In the search field below All Items, enter nmstate and click Enter to search for the Kubernetes NMState Operator.

  3. Click on the Kubernetes NMState Operator search result.

  4. Click on Install to open the Install Operator window.

  5. Click Install to install the Operator.

  6. After the Operator finishes installing, click View Operator.

  7. Under Provided APIs, click Create Instance to open the dialog box for creating an instance of kubernetes-nmstate.

  8. In the Name field of the dialog box, ensure the name of the instance is nmstate.

    The name restriction is a known issue. The instance is a singleton for the entire cluster.

  9. Accept the default settings and click Create to create the instance.

Summary

After you install the Kubernetes NMState Operator, the Operator has deployed the NMState State Controller as a daemon set across all of the cluster nodes.

Installing the Kubernetes NMState Operator using the CLI

You can install the Kubernetes NMState Operator by using the OpenShift CLI (oc). After it is installed, the Operator can deploy the NMState State Controller as a daemon set across all of the cluster nodes.

Prerequisites

  • You have installed the OpenShift CLI (oc).

  • You are logged in as a user with cluster-admin privileges.

Procedure

  1. Create the nmstate Operator namespace:

    $ cat << EOF | oc apply -f -
apiVersion: v1
kind: Namespace
metadata:
  name: openshift-nmstate
spec:
  finalizers:
  - kubernetes
EOF

  2. Create the OperatorGroup:

    $ cat << EOF | oc apply -f -
apiVersion: operators.coreos.com/v1
kind: OperatorGroup
metadata:
  name: openshift-nmstate
  namespace: openshift-nmstate
spec:
  targetNamespaces:
  - openshift-nmstate
EOF

  3. Subscribe to the nmstate Operator:

    $ cat << EOF| oc apply -f -
apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
  name: kubernetes-nmstate-operator
  namespace: openshift-nmstate
spec:
  channel: stable
  installPlanApproval: Automatic
  name: kubernetes-nmstate-operator
  source: redhat-operators
  sourceNamespace: openshift-marketplace
EOF

  4. Confirm the ClusterServiceVersion (CSV) status for the nmstate Operator deployment equals Succeeded:

    $ oc get clusterserviceversion -n openshift-nmstate \
 -o custom-columns=Name:.metadata.name,Phase:.status.phase
    Example output
    Name                                             Phase
kubernetes-nmstate-operator.4.17.0-202210210157   Succeeded

  5. Create an instance of the nmstate Operator:

    $ cat << EOF | oc apply -f -
apiVersion: nmstate.io/v1
kind: NMState
metadata:
  name: nmstate
EOF

  6. Verify the pods for NMState Operator are running:

    $ oc get pod -n openshift-nmstate
    Example output
    Name                                      Ready   Status  Restarts  Age
pod/nmstate-cert-manager-5b47d8dddf-5wnb5   1/1   Running  0         77s
pod/nmstate-console-plugin-d6b76c6b9-4dcwm  1/1   Running  0         77s
pod/nmstate-handler-6v7rm                   1/1   Running  0         77s
pod/nmstate-handler-bjcxw                   1/1   Running  0         77s
pod/nmstate-handler-fv6m2                   1/1   Running  0         77s
pod/nmstate-handler-kb8j6                   1/1   Running  0         77s
pod/nmstate-handler-wn55p                   1/1   Running  0         77s
pod/nmstate-operator-f6bb869b6-v5m92        1/1   Running  0        4m51s
pod/nmstate-webhook-66d6bbd84b-6n674        1/1   Running  0         77s
pod/nmstate-webhook-66d6bbd84b-vlzrd        1/1   Running  0         77s

Viewing metrics collected by the Kubernetes NMState Operator

The Kubernetes NMState Operator, kubernetes-nmstate-operator, can collect metrics from the kubernetes_nmstate_features_applied component and expose them as ready-to-use metrics. As a use case for viewing metrics, consider a situation where you created a NodeNetworkConfigurationPolicy custom resource and you want to confirm that the policy is active.

The kubernetes_nmstate_features_applied metrics are not an API and might change between OpenShift Container Platform versions.

In the Developer and Administrator perspectives, the Metrics UI includes some predefined CPU, memory, bandwidth, and network packet queries for the selected project. You can run custom Prometheus Query Language (PromQL) queries for CPU, memory, bandwidth, network packet and application metrics for the project.

The following example demonstrates a NodeNetworkConfigurationPolicy manifest example that is applied to an OpenShift Container Platform cluster:

# ...
interfaces:
  - name: br1
    type: linux-bridge
    state: up
    ipv4:
      enabled: true
      dhcp: true
      dhcp-custom-hostname: foo
    bridge:
      options:
        stp:
          enabled: false
      port: []
# ...

The NodeNetworkConfigurationPolicy manifest exposes metrics and makes them available to the Cluster Monitoring Operator (CMO). The following example shows some exposed metrics:

controller_runtime_reconcile_time_seconds_bucket{controller="nodenetworkconfigurationenactment",le="0.005"} 16
controller_runtime_reconcile_time_seconds_bucket{controller="nodenetworkconfigurationenactment",le="0.01"} 16
controller_runtime_reconcile_time_seconds_bucket{controller="nodenetworkconfigurationenactment",le="0.025"} 16
...
# HELP kubernetes_nmstate_features_applied Number of nmstate features applied labeled by its name
# TYPE kubernetes_nmstate_features_applied gauge
kubernetes_nmstate_features_applied{name="dhcpv4-custom-hostname"} 1
Prerequisites

  • You have installed the OpenShift CLI (oc).

  • You have logged in to the web console as the administrator and installed the Kubernetes NMState Operator.

  • You have access to the cluster as a developer or as a user with view permissions for the project that you are viewing metrics for.

  • You have enabled monitoring for user-defined projects.

  • You have deployed a service in a user-defined project.

  • You have created a NodeNetworkConfigurationPolicy manifest and applied it to your cluster.

Procedure

  1. If you want to view the metrics from the Developer perspective in the OpenShift Container Platform web console, complete the following tasks:

    1. Click Observe.

    2. To view the metrics of a specific project, select the project in the Project: list. For example, openshift-nmstate.

    3. Click the Metrics tab.

    4. To visualize the metrics on the plot, select a query from the Select query list or create a custom PromQL query based on the selected query by selecting Show PromQL.

      In the Developer perspective, you can only run one query at a time.

  2. If you want to view the metrics from the Administrator perspective in the OpenShift Container Platform web console, complete the following tasks:

    1. Click Observe → Metrics.

    2. Enter kubernetes_nmstate_features_applied in the Expression field.

    3. Click Add query and then Run queries.

  3. To explore the visualized metrics, do any of the following tasks:

    1. To zoom into the plot and change the time range, do any of the following tasks:

      • To visually select the time range, click and drag on the plot horizontally.

      • To select the time range, use the menu which is in the upper left of the console.

    2. To reset the time range, select Reset zoom.

    3. To display the output for all the queries at a specific point in time, hold the mouse cursor on the plot at that point. The query output displays in a pop-up box.

Additional resources

Next steps