From a routing perspective, loopbacks are a great solution as far as reachability of a device is concerned. I have run into an issue where i had a loopback interface on the router, non routable. Had that interface on for testing. When MGCP process reset, it for some reason got bound to the loopback address and started causing oneway audio issues, as the loopback was non routable.
So definitely make sure that you use a routable loopback address and also use the bind commands for media and control to the loopback interface.
I have also seen another bug (dont recollect the bug id) where even after physically binding the loopback using the bind commands, when mgcp process resets, the bind media and bind control command seems to lose the ip address. (Sh mgcp shows blank output).
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.