Testing Domain Name resolution services for OpenShift 4.x installs

** NOTE ** As of OpenShift 4.4+ the etcd-operator has been added, and pre-flight checks for etcd domain names and SRV records are no longer necessary. As noted in the documentation for OpenShift 4.4+ these domain names do not have to be included in the DNS providers configuration.

If your OpenShift UPI installation is failing, it is important to inspect infrastructure DNS configuration...