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About the Kubernetes NMState Operator

The Kubernetes NMState Operator provides a Kubernetes API for performing state-driven network configuration across the OKD 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, and LinuxONE installations.

When using OVN-Kubernetes, changing the default gateway interface is not supported.

Before you can use NMState with OKD, you must install the Kubernetes NMState Operator.

The Kubernetes NMState Operator updates the network configuration of a secondary NIC. It cannot update the network configuration of the primary NIC or the br-ex bridge.

OKD 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 manifest 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 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

Once complete, 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:
  labels:
    kubernetes.io/metadata.name: openshift-nmstate
    name: openshift-nmstate
  name: openshift-nmstate
spec:
  finalizers:
  - kubernetes
EOF

  2. Create the OperatorGroup:

    $ cat << EOF | oc apply -f -
apiVersion: operators.coreos.com/v1
kind: OperatorGroup
metadata:
  annotations:
    olm.providedAPIs: NMState.v1.nmstate.io
  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:
  labels:
    operators.coreos.com/kubernetes-nmstate-operator.openshift-nmstate: ""
  name: kubernetes-nmstate-operator
  namespace: openshift-nmstate
spec:
  channel: stable
  installPlanApproval: Automatic
  name: kubernetes-nmstate-operator
  source: redhat-operators
  sourceNamespace: openshift-marketplace
EOF

  4. Create instance of the nmstate operator:

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

  • Confirm that the deployment for the nmstate operator is running:

    oc get clusterserviceversion -n openshift-nmstate \
 -o custom-columns=Name:.metadata.name,Phase:.status.phase
    Example output
    Name                                             Phase
kubernetes-nmstate-operator.4.11.0-202208120157   Succeeded