What is the best way to quickly update multiple client domain DNS and keep switchover downtime to a minimum?
I am currently using vanity nameservers and glue record on my Primary domain, at the domain registrar like so;
1) mycompany.com which has nameservers of ns1.powerdns.com & ns2.powerdns.com (from Host) and I have glue records of my vanity nameservers; ns1.mycompany.com (IP 126.96.36.199) & ns1.mycompany.com (IP 188.8.131.52). 2) in Host providers DNS managment, I have set up NS records to point to the ns1.powerdns.com & ns2.powerdns.com and I also have A records in there. 3) Client domains set up in server with zone records.
This allows me to point my client domains to the vanity nameservers e.g. myclient1.com > ns1.mycompany.com and ns2.mycompany.com, myclient2.com > ns1.mycompany.com and ns2.mycompany.com and so on
But I need to move DNS away from hosting provider as it has been unreliable. I don't want the additional complexity of managing my own DNS server.
So my question is this:
If I move to e.g. Cloudflare or DNSME (the latter seem to have free vanity nameservers support) - what would the best set up be?
A) Would I simply set up one "master" DNS record for mycompany.com that points to my server IP / nameservers - and that would result in the client domains automatically following / re-routing / bouncing their DNS lookup through the DNSME "master" record? What is the likely client domain interruption with this method?
B) Or should I update all client domain registrar records to point to the DNSME NS individually and then set up separate records (or a template) for each client domain to point to my server?
I assume only B above would mean any client domain nameserver changes would benefit from CDN type propagation?