Using LVS (Linux Virtual Server) for doing DNS HA

Solution 1:

You should be able to configure DNS load balancing pretty easily with LVS in DR mode. Personally I would use Ldirectord rather than Piranaha (which is old and buggy), but either should work.

Like you said you will need to configure your firewall mark for the correct TCP and UDP ports, then load balance all packets that are marked to your backend server(s). I assume you won't need persistence for DNS (wouldn't work for UDP anyway).

I think the step you are probably missing is to allow the backend servers to respond to the traffic you are sending - commonly know as the ARP problem. If you have Windows servers then use this method. Or for Linux the simplest method is to use an iptables redirect:

iptables -t nat -A PREROUTING -p tcp -d <VIP> -j REDIRECT

Its explained in more detail on page 21 of the http://loadbalancer.org quick start guide.

If you need any help, post your config and I'll take a look.