Can someone definitively explain Clustered DNS? The instructions make no sense.


May 17, 2009
I know this is pretty dumb, but I just don't understand precisely how and why to set things up with clustered DNS - I mean, I have it working for the most part, but things that I assume would just automatically occur don't seem to work, but yet making DNS changes on a machine up the hierarchy does seem to cascade down.

Ok I suppose I should start at the bottom. I have two standalone DNS Only servers set up, and they're configured to cluster with another server that acts as my "central" DNS server - it's not for making public requests to, but it's meant to act as an easy place to centralize my DNS around, so that if I add another public-facing DNS server, I don't have to add every single last cPanel slice, I only add the central one.

So, on these DNS only cPanels, I've added this "central" cPanel, and on the DNS only install, it has the central one set as "standalone". I've done this because the instructions are as confusing as hell - what the hell "this" server is it referring to? The current local server you're on, or one of the ones in the list? So is this meant to be set as standalone? I really have no idea. If anything comes of this, it'd be nice if the instructions clarified what it means by "this", as it's ambiguous to say the least.

On the "central" one, I have the two public-facing servers set as "synchronize", which seems to work if I force a sync, and it pushes the records down to the public-facing ones, so why, if i'm actually ON one of the public-facing ones does forcing a sync do nothing? Am I doing something wrong? The documentation is vastly unclear on this.

on the outlying slices, the ones that host heaps of sites, I have the central server added, and it is marked as "synchronize". Again, it seems to work if i force sync or do a DNS update, but if, as an example, I have a bunch of sites on an outlying slice and I add it to the cluster, nothing gets synced until I force it FROM the outlying one, it doesn't propagate when added nor if I try it on the central one.

So is this configured right? The diagram it generates seems to reflect what I am trying to achieve, it just doesn't seem to always push records around like you'd expect - as in, if I add a new public-facing DNS to the cluster, do I have to go in to the "central" server to push it all its records?