Glue Records
Definition
Glue Records are special DNS records you configure in your registrar (Google Domains, GoDaddy, Namecheap, etc.) that allow you to configure special DNS records for you domain so root nameservers can resolve other domains you manage.
Reseller
In the example below, I have created a reseller domain called premiumwpreseller.org (your domain will be different).
I want to use Glue Records for this domain, so all of my client property domains will use my
nameservers for their DNS:
ns1.premiumwpreseller.orgns2.premiumwpreseller.orgns3.premiumwpreseller.orgns4.premiumwpreseller.org
In order for this to work, I have to log in to my registrar and configure glue records (below).
Reseller Registrar
In my registrar, I have added glue records (registered hosts) that will allow my DNS servers to be used for other client properties:
Reseller Clients
In your Reseller Client domain(s), you can now configure those domains to use your domain as Vanity Nameservers:
Reseller Client Registrar
In my registrar, I have added the nameservers (ns{1,2,3,4}.premiumwpreseller.org) for my client domain (premiumjunkremoval.org)
and saved my settings.
You DO NOT specify Glue Records on the client domains! Glue Records only exist on your main reseller domain.