We have a small server stack in our operation, one of which is a dedicated blade server running Ubuntu 12.04LTS (we'll call this UBU). This server is our Cloudmin master running Cloudmin Pro 9.4.
Unfortunate for us, this is also the oldest server in the stack (as evidenced by running an EOL version of Ubuntu). In an effort to migrate away from deprecated technology, I set up a brand new blade server with CentOS 7 1810 with an installation of Cloudmin Pro 9.4 (we'll call this CCE7). PS - there are 7 other blade servers acting as KVM hosts on this network.
I followed the instructions as per: https://www.virtualmin.com/documentation/cloudmin/repl.
We now have UBU (master) replicating to CCE7 (Secondary). In theory, if UBU goes down, CCE7 should simply take over, should it not?
The concerns are that several critical services are not replicated, such as; DNS (Bind 9), DHCP (ISC DHCPd Version 4.1), postfix (not as essential but still on the radar).
All of our virtual machines are "hardcoded" during creation by Cloudmin to point DNS to UBU, which forwards external requests to our firewall. How do we go about accommodating this?
Is there a strategy to use whereby the aforementioned services are also migrated? Or do they need to be configured by an admin?
What about existing DNS configurations on VMs? Do they need to be changed manually?
Where we are headed with this is that we intend to simulate a "crash" of the master to allow the secondary to take over. The intent is to make CCE7 a standalone Cloudmin master so that we can retire UBU altogether.
Thank you in advance for any information you can provide.