Cluster ingress operator creates router deployments with affinity rules when running in a cluster with non-HA infrastructure plane (InfrastructureTopology=="SingleReplica") and "NodePortService" endpoint publishing strategy. With only one worker node available, rolling update of router-default stalls.

All

Create a single worker node cluster with "NodePortService" endpoint publishing strategy and try to restart the default router. Restart will not go through.

1. Create a single worker node OCP cluster with HA control plane (ControlPlaneTopology=="HighlyAvailable"/"External") and one worker node (InfrastructureTopology=="SingleReplica") using "NodePortService" endpoint publishing strategy. The operator will create "ingress-default" deployment with "podAntiAffinity" block, even though the number of nodes where ingress pods can be scheduled is only one:
```
apiVersion: apps/v1
kind: Deployment
metadata:
  ...
  name: router-default
  namespace: openshift-ingress
  ...
spec:
  ...
  replicas: 1
  ...
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 50%
    type: RollingUpdate
  template:
    ...
    spec:
      affinity:
        ...
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
          - labelSelector:
              matchExpressions:
              - key: ingresscontroller.operator.openshift.io/deployment-ingresscontroller
                operator: In
                values:
                - default
              - key: ingresscontroller.operator.openshift.io/hash
                operator: In
                values:
                - 559d6c97f4
            topologyKey: kubernetes.io/hostname
...
```

2. Restart the default router

```
oc rollout restart deployment router-default -n openshift-ingress
```
 

Deployment restart does not complete and hangs forever:

```
oc get po -n openshift-ingress
NAME                              READY   STATUS    RESTARTS   AGE
router-default-58d88f8bf6-cxnjk   0/1     Pending   0          2s
router-default-5bb8c8985b-kdg92   1/1     Running   0          2d23h
```

Deployment restart completes