[Samba] how do I setup a second samba4 DC with replication, etc?

[Aaron Solochek]

I have 1 samba4 server setup as a domain controller for FOO.COM.  I want to add
a second for redundancy.  I really don't want to mess this up, and I can't find
a clear guide online.  Can anyone tell me the proper commands?

Thanks.

-Aaron