text: The default service clusterIP addresses are from the OpenShift Container Platform internal 
  network and they are used to permit Pods to access each other. 
  
  To permit external access to the service, more externalIP and ingressIP addresses that are 
  external to the cluster can be assigned to the service. These externalIP addresses also can 
  be virtual IP addresses that provide highly available access to the service. 
  
  Services are assigned an IP address and port pair that, when accessed, proxy the 
  connections to an appropriate backing pod. A service uses a label selector to find all the 
  containers that are running that provide a specific network service on a specific port, as 
  shown in Example 4-1. 