Replacing a server in a cPanel DNS cluster

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Posted by Bdzzld, 10-06-2008, 04:59 AM
Hi, I've currently got three cPanel servers working in a DNS cluster : server 1 : server1.domainname.xxx server 2 : server2.domainname.xxx server 3 : server2.domainname.xxx DNS1 : dns1.domainname.xxx DNS2 : dns1.domainname.xxx DNS3 : dns1.domainname.xxx Because server1.domainname.xxx is already three years of age I'd like to replace this server - better safe than sorry - with a new one (server4.domainname.xxx). What's the best way to add server4.domainname.xxx to the cluster and move all accounts from server1.domainname.xxx to server4.domainname.xxx without the least downtime possible ? Thanks.
Posted by Tech-Hosts Team, 10-06-2008, 04:33 PM
Hi, I'd say your best bet is to migrate it like you always would, especially if you are calling the new server, server4. So i'd recommend you just setup server 4 as you would normally. Join it to the DNS cluster, and migrate the accounts to the new server. Then you can just pull server 1 offline...
Posted by Bdzzld, 10-07-2008, 11:45 AM
Thanks for your reply. Will migrating the accounts from one server to another when both servers are in the same DNS cluster cause any (DNS) problems? I.a.w. What are your suggestions to do this safely and with no downtime? Thanks again.
Posted by Tech-Hosts Team, 10-07-2008, 12:55 PM
Being in the same DNS cluster should cause NO downtime at all. All 3 servers use the same Name Servers yes? Test it by moving an account that's not important over, terminate on server 1 and see if it still works. In theory - it should work, if not, then we'll look at another method thats about 20x more complicated.
Posted by cPanelDavidG, 10-07-2008, 12:58 PM
Migrating among servers in a DNS Cluster shouldn't cause DNS issues.
Posted by Xous, 10-07-2008, 03:11 PM
Hi, That solution seems somewhat less than ideal as you probably already have a bunch of domains using ns1.example.net., ns2.example.net., and ns3.example.net. I would bet a some of these clients do not have all their domain names registered with you so at least some of these would result in some erratic DNS issues. 1) I would bring up server4.example.net. Get cPanel installed and configure it for clustering. Note I've never configured clustering but iirc all it is is a script that runs rsync on the zone files and generates a configuration file. 2) So you should be able to get server4 up and answering DNS requests without much trouble. At this point no external DNS requests would be hitting server4. (This assumes you are using a different IP address than the main IP address for ns1.example.net.) 3) Now all you need to do is remove the ns1.example.net IP address from server1.example.net and add it to server4.example.net. If you did all your testing right you should have only had a few minutes of downtime for ns1.example.net. Note: this assumes that you do not have any accounts on server1. If you do you will need to migrate the accounts to the new server before doing 2. Last edited by Xous; 10-07-2008 at 03:15 PM.

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