Google's Cloud DNS service is used by the OpenShift installer to configure cluster DNS resolution and provide name lookup
for the cluster to the outside world. To use OpenShift, you must have created a public zone in Google Cloud DNS in
the same project as your OpenShift cluster. You must also ensure the zone is "authoritative" for the domain. There are
two ways to do this outlined below: root domain and subdomain. A root domain is example.com. A subdomain is of
the form clusters.example.com.
The below sections identify how to ensure your DNS zone is authoritative for a domain.
You may skip this step if using an existing domain and registrar. You will move the authoritative DNS to Google Cloud DNS or submit a delegation request for a subdomain in a later step.
You can use Google Domains to purchase a domain or use your preferred registrar.
Whether using a root domain or a subdomain, you must create a public DNS zone.
GCP: Creating a Public DNS Zone
To use the root domain, you'd create the DNS zone with the value example.com. To use a subdomain, you'd
create a zone with the value clusters.example.com. (Use appropriate domain values for your situation.)
For either a root domain example.com or a subdomain clusters.example.com, you must extract the new
authoritative nameservers from the DNS zone records.
GCP: Getting the Name Servers for a Public DNS Zone
Each registrar requires a slightly different procedure. Using the four nameserver values from the previous step, you will update the registrar records to the Google Cloud DNS nameservers.
If you are migrating your root domain to Google Cloud DNS, you should migrate existing DNS records:
For a subdomain of example.com (e.g. clusters.example.com), you must add delegation records to the parent/root domain. This may require a request to your company's IT department or the division which controls the root domain and DNS services for your company.