Description of problem:

lifecycle.posStart does not have network connectivity on OpenShiftSDN CNI. (OVNKubernetes does not have the issue)


Version-Release number of selected component (if applicable):
4.10

How reproducible:
always

Steps to Reproduce:
1. create statefulset
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$ oc create -f statefulset.yaml
$ cat statefulset.yaml
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: httpd
spec:
  serviceName: "httpd"
  replicas: 1
  selector:
    matchLabels:
      app: httpd
  template:
    metadata:
      labels:
        app: httpd
    spec:
      containers:
      - name: httpd
        image: registry.redhat.io/rhel8/httpd-24:1-191
        ports:
        - containerPort: 80
          name: web
        lifecycle:
          postStart:
            exec:
              command:
              - /bin/sh
              - -c
              - curl -k https://<IP:PORT> > /tmp/urltest.txt
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Actual results:

PostStartHook fails 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
36s         Normal    Killing               pod/httpd-0         FailedPostStartHook
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


Expected results:

PostStartHook should not fail.



Additional info:

by adding a dummy initContainers, you can workaround the issue. 
something like this:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    spec:
      initContainers:
      - name: init-myservice
        image: busybox:1.28
        command: ['sh', '-c', 'sleep 2']
      containers:
      - name: httpd
        image: registry.redhat.io/rhel8/httpd-24:1-191
        ports:
        - containerPort: 80
          name: web
        lifecycle:
          postStart:
            exec:
              command:
              - /bin/sh
              - -c
              - curl -k <IP:PORT> > /tmp/urltest.txt
        ....
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~