Description of problem:

When the ingress operator reconciles an ingresscontroller that has the "NodePortService" endpoint publishing strategy type, the operator gets the ingresscontroller's nodeport service (if one exists) from the API to determine whether the operator needs to create or update the service.  If the service does not exist, the operator creates it, and if the service does exist, the operator compares it with what the operator expects to get in order to determine whether an update is needed for that service.  In this comparison, if the API has set a value for the service's clusterIPs field, the operator detects the update and tries to set the clusterIPs field back to the empty value.  The operator should not update the service in response to API defaulting.


Version-Release number of selected component (if applicable):

The clusterIPs field is new in Kubernetes 1.20 (OpenShift 4.7).


Steps to Reproduce:

1. Launch a new cluster.

2. Create an ingresscontroller with the "NodePortService" endpoint publishing strategy:

    oc create -f - <<'EOF'
    apiVersion: operator.openshift.io/v1
    kind: IngressController
    metadata:
      name: nodeport
      namespace: openshift-ingress-operator
    spec:
      replicas: 1
      domain: example.com
      endpointPublishingStrategy:
        type: NodePortService
    EOF

3. Check the ingress operator's logs:

    oc -n openshift-ingress-operator logs deploy/ingress-operator -c ingress-operator


Actual results:

The ingress operator's logs have "updated NodePort service" repeated several times.


Expected results:

The ingress operator should ignore the clusterIPs field's value and should not log "updated NodePort service" unless the service is updated outside of API defaulting.