How to make a DHCP server on virtual machine serves other virtual machines(on different physical machines)

clusterdhcpvirtual-machinesvirtualbox

I'm building a virtual cluster with VirtualBox and Opensuse. I have 10 physical machines and need several vms on each. The virtual machines are supposed to be in a "private" network, but still have internet access. I was asked to set up a virtual head node working as DHCP server. I installed DHCP server on the virtual head node and it seems works. On VirtualBox I set 2 network adapters to the head node, one bridged adapter and one internal network.
One vm on the same physical machine has been set nic as internal network adapter. The vm
can get IP address (so DHCP works) but can't access internet. What should I do?
Specifically, what network adapter should I choose for head-node and work-nodes in VirtualBox? What in the virtual machines should I do?

Best Answer

Your proposed set up will be a huge pain to implement the way you describe.

You can save yourself a headache if your physical machines have 2 physical ethernet ports. If they do, connect the 2nd port on each machine to a physical switch/router and use that physical port for the VMs. Then connect the switch/router to the internet.