Moving from separate-server DNS to clustered DNSONLY servers

ashworth102680

Active Member
May 3, 2007
26
1
153
For years we've just had the one server (now several), and each server had its format for single-server nameservers:

servername1.mydomain.com
servername2.mydomain.com

Now with multiple servers, and confused clients, we're wanting to setup clustered DNS. A single list of nameservers that any hosting server can make use of, and for better redundancy within our infrastructure.

My primary question is how we roll it out to customers. I already know pretty well how to set it up, link them to various hosting servers, etc. What I don't know is how this will impact clients.

  1. Can we have some clients on the new NS servers, and others on the old ones?
  2. What happens if some clients are slow to respond to our request to update nameservers?
  3. Do we need to plan for a cutover window?
  4. Are there any conflicts I need to know about, such as the same DNS zone being present on more than one server?

We're still in the planning phase of this, but want to move quickly. Just looking to square away a couple of those important items. Many customers control their own domain name, and some don't even know their current password I'm sure, so I'm trying to anticipate some of the issues we'll run into.

It would be great if we can somehow do a slow rollout, where early adopters can jump onboard when they want to the new DNS servers, and we can continue to transition others over time as communication between us and the client allows.

Thanks for your help. Should be an interesting thread!
 

cPanelMichael

Administrator
Staff member
Apr 11, 2011
47,913
2,203
363
Hello :)

Are the domain names assigned name servers that run on the servers they are hosted on in the existing setup? EX:

A. domain123.com is hosted on server1.com.
B. domain123.com uses ns1.server1.com and ns2.server1.com.
C. ns1.server1.com and ns2.server1.com are assigned IP addresses associated with server1.com.

If so, you can setup a DNS cluster and leave the local name server enabled. This will allow domain names to switch to the new name servers, or continue to use the name servers for the local machine. The DNS Zones that are synced to the remote DNS-Only servers will remain on the local server anyway, so there will not be an issue with duplicate zones unless you attempt to create the same domain name on another server on the same cluster. You can disable your local name server via WHM when you are ready to force customers to switch name servers.

Thank you.
 

ashworth102680

Active Member
May 3, 2007
26
1
153
Are the domain names assigned name servers that run on the servers they are hosted on in the existing setup? EX:

A. domain123.com is hosted on server1.com.
B. domain123.com uses ns1.server1.com and ns2.server1.com.
C. ns1.server1.com and ns2.server1.com are assigned IP addresses associated with server1.com.
I think I understand what you're asking. Here's what we have right now.

Code:
firstservername.mydomain.com (hostname/server)
-- firstservername1.mydomain.com (a record + dns served from this server)
-- firstservername2.mydomain.com (a record + dns served from this server)
----- domain1.com (hosted on this server, uses above nameservers)
----- domain2.com (hosted on this server, uses above nameservers)
----- domain3.com (hosted on this server, uses above nameservers)

secondservername.mydomain.com (hostname/server)
-- secondservername1.mydomain.com (a record + dns served from this server)
-- secondservername2.mydomain.com (a record + dns served from this server)
----- domain4.com (hosted on this server, uses above nameservers)
----- domain5.com (hosted on this server, uses above nameservers)
----- domain6.com (hosted on this server, uses above nameservers)

thirdservername.mydomain.com (hostname/server)
-- thirdservername1.mydomain.com (a record + dns served from this server)
-- thirdservername2.mydomain.com (a record + dns served from this server)
----- domain7.com (hosted on this server, uses above nameservers)
----- domain8.com (hosted on this server, uses above nameservers)
----- domain9.com (hosted on this server, uses above nameservers)
Ultimately I'd love to just have clients always use the following, 100% of the time:

Code:
ns1.mydomain.com
ns2.mydomain.com
ns3.mydomain.com
ns4.mydomain.com
Hopefully that makes sense. Thanks for the quick response!
 

vlee

Well-Known Member
Oct 13, 2005
374
26
178
Spokane, Washington
cPanel Access Level
Root Administrator
I am running 3 DNS Only Servers. for a client that I help maintain their servers

Server 1= dns1.domain.com
NS= ns1.domain.com

Server 2= dns2.domain.com
NS= ns2.domain.com

Server 3= dns3.domain.com
NS= ns3.domain.com

This works out really well and the web server sync to each DNS Only Server as a cluster. cPanel DNS Only Servers are easy to to setup.

This client was somewhat like you are now. I setup the new DNS Only Servers waited at least 24 hours before changing the name server records in in domain registrar to reflect the changes, then started to change the web server to cluster mode and disabled bind.
 

ashworth102680

Active Member
May 3, 2007
26
1
153
Veldon, it's been a long time since our kicking off the Network Redux forums.

Thanks for chiming in my friend! :D
 

cPanelMichael

Administrator
Staff member
Apr 11, 2011
47,913
2,203
363
To answer your earlier question, yes, you are using the type of setup that I referenced in my previous post. Thus, my advice in my previous answer does apply to you.

I'm also a little concerned by this as well. If we go this route, not all customers will be able to use the name servers due to this known security bug. Unless it's fixed...in which case I wasn't aware it was. Any update you may be able to share?

http://forums.cpanel.net/f185/all-root-owned-dns-zones-available-all-resellers-307992.html
Resellers are only granted access to setup a DNS cluster if you enable the "Clustering" feature for them in "WHM Home » Resellers » Edit Reseller Nameservers and Privileges". You can still setup a DNS cluster as "root" and all DNS Zones will be synced. The "clustering" option does not have to be enabled in order for the DNS zones under a reseller account to synchronize to other servers in the cluster.