Up until now, I hadn't bothered with the DNS, as we've only got a single static IP address. But we're getting an upgrade to our network connection soon and will get a small block of IP addresses, so I've moved my attention to getting the DNS working (hence the other thread where I was testing things out on my laptop at home first, before attacking the problem on our cluster). I attempted to create a DNS zone but the jobqueue is stuck on this (I can perform other actions and those complete, but the DNS actions won't budge). I've got it so that the two load balancers I have set up are also going to provide the DNS as "ns1" and "ns2". I think that what's happened is that the one node can't access the mysql on the other node (the configuration of "ns1" isn't being changed when I manually "dig" on that node). That I might need to grant privileges or something. How would I diagnose and fix this? I can't remember which way around it is - do the slaves access the master, or does the master access the slaves?