Router shard pod can not schedule in OpenShift 4

Issue

• The ingress cluster operator gets into degraded state due to a router pod not being in the Running state.
• There are a combination of "default" and custom or "sharded" ingresscontroller definitions for router pods
• Alerts:

message = Deployment openshift-ingress/router-sharded has not matched the expected number of replicas for longer than 15 minutes.

message = Cluster operator ingress has been degraded for 10 minutes. The operator is degraded because IngressControllersDegraded and cluster upgrades will be unstable.

• Describing the pod:

# oc describe pod router-sharded-x -n openshift-ingress
Name:                 router-sharded-8477bc9b79-bx92r
Namespace:            openshift-ingress
Events:
 Type     Reason            Age    From               Message
  ----     ------            ----   ----               -------
  Warning  FailedScheduling  2m13s  default-scheduler  0/10 nodes are available: 3 node(s) didn't have free ports for the requested pod ports, 7 node(s) didn't match node selector.