I have installed ispconfig3 on ubuntu 16.04 using the perfect server guide. I only used standard install on the "primary" server. everything functions as expected with all "optional" steps in the guide. now my question is, can i spin up a secondary ispconfig using the same steps, and then use expert mode when actually installing ISP config to set the proper variables to make it a secondary? the only guide i found was a multiserver with 5 servers. I just want a secondary dns to act as a part of my public facing name servers to resolve our hosted servers. It works already using just one, but the boss wants best practices enforced so here i am!