Cluster Network Operator in OKD

The Cluster Network Operator (CNO) deploys and manages the cluster network components on an OKD cluster, including the Container Network Interface (CNI) default network provider plug-in selected for the cluster during installation.

Cluster Network Operator

The Cluster Network Operator implements the network API from the operator.openshift.io API group. The Operator deploys the OpenShift SDN default Container Network Interface (CNI) network provider plug-in, or the default network provider plug-in that you selected during cluster installation, by using a daemon set.

Procedure

The Cluster Network Operator is deployed during installation as a Kubernetes Deployment.

1. Run the following command to view the Deployment status:

   $ oc get -n openshift-network-operator deployment/network-operator

   Example output

   NAME               READY   UP-TO-DATE   AVAILABLE   AGE
   network-operator   1/1     1            1           56m

2. Run the following command to view the state of the Cluster Network Operator:

   $ oc get clusteroperator/network

   Example output

   NAME      VERSION   AVAILABLE   PROGRESSING   DEGRADED   SINCE
   network   4.5.4     True        False         False      50m

   The following fields provide information about the status of the operator: AVAILABLE, PROGRESSING, and DEGRADED. The AVAILABLE field is True when the Cluster Network Operator reports an available status condition.

Viewing the cluster network configuration

Every new OKD installation has a network.config object named cluster.

Procedure

• Use the oc describe command to view the cluster network configuration:

  $ oc describe network.config/cluster

  Example output

  Name:         cluster
  Namespace:
  Labels:       <none>
  Annotations:  <none>
  API Version:  config.openshift.io/v1
  Kind:         Network
  Metadata:
    Self Link:           /apis/config.openshift.io/v1/networks/cluster
  Spec: (1)
    Cluster Network:
      Cidr:         10.128.0.0/14
      Host Prefix:  23
    Network Type:   OpenShiftSDN
    Service Network:
      172.30.0.0/16
  Status: (2)
    Cluster Network:
      Cidr:               10.128.0.0/14
      Host Prefix:        23
    Cluster Network MTU:  8951
    Network Type:         OpenShiftSDN
    Service Network:
      172.30.0.0/16
  Events:  <none>

  1	The Spec field displays the configured state of the cluster network.
  2	The Status field displays the current state of the cluster network configuration.

Viewing Cluster Network Operator status

You can inspect the status and view the details of the Cluster Network Operator using the oc describe command.

Procedure

• Run the following command to view the status of the Cluster Network Operator:

  $ oc describe clusteroperators/network

Viewing Cluster Network Operator logs

You can view Cluster Network Operator logs by using the oc logs command.

Procedure

• Run the following command to view the logs of the Cluster Network Operator:

  $ oc logs --namespace=openshift-network-operator deployment/network-operator

Cluster Network Operator configuration

The configuration for the cluster network is specified as part of the Cluster Network Operator (CNO) configuration and stored in a custom resource (CR) object that is named cluster. The CR specifies the fields for the Network API in the operator.openshift.io API group.

The CNO configuration inherits the following fields during cluster installation from the Network API in the Network.config.openshift.io API group and these fields cannot be changed:

clusterNetwork

IP address pools from which pod IP addresses are allocated.

serviceNetwork

IP address pool for services.

defaultNetwork.type

Cluster network provider, such as OpenShift SDN or OVN-Kubernetes.

You can specify the cluster network provider configuration for your cluster by setting the fields for the defaultNetwork object in the CNO object named cluster.

Cluster Network Operator configuration object

The fields for the Cluster Network Operator (CNO) are described in the following table:

spec:
  clusterNetwork:
  - cidr: 10.128.0.0/19
    hostPrefix: 23
  - cidr: 10.128.32.0/19
    hostPrefix: 23

spec:
  serviceNetwork:
  - 172.30.0.0/14

defaultNetwork object configuration

The values for the defaultNetwork object are defined in the following table:

Configuration for the OpenShift SDN CNI cluster network provider

The following table describes the configuration fields for the OpenShift SDN Container Network Interface (CNI) cluster network provider.

Example OpenShift SDN configuration

defaultNetwork:
  type: OpenShiftSDN
  openshiftSDNConfig:
    mode: NetworkPolicy
    mtu: 1450
    vxlanPort: 4789

Configuration for the OVN-Kubernetes CNI cluster network provider

The following table describes the configuration fields for the OVN-Kubernetes CNI cluster network provider.

Example OVN-Kubernetes configuration

defaultNetwork:
  type: OVNKubernetes
  ovnKubernetesConfig:
    mtu: 1400
    genevePort: 6081
    ipsecConfig: {}

kubeProxyConfig object configuration

The values for the kubeProxyConfig object are defined in the following table:

kubeProxyConfig:
  proxyArguments:
    iptables-min-sync-period:
    - 0s

Cluster Network Operator example configuration

A complete CNO configuration is specified in the following example:

Example Cluster Network Operator object

apiVersion: operator.openshift.io/v1
kind: Network
metadata:
  name: cluster
spec:
  clusterNetwork: (1)
  - cidr: 10.128.0.0/14
    hostPrefix: 23
  serviceNetwork: (1)
  - 172.30.0.0/16
  defaultNetwork: (1)
    type: OpenShiftSDN
    openshiftSDNConfig:
      mode: NetworkPolicy
      mtu: 1450
      vxlanPort: 4789
  kubeProxyConfig:
    iptablesSyncPeriod: 30s
    proxyArguments:
      iptables-min-sync-period:
      - 0s

Additional resources

• Network API in the operator.openshift.io API group