We have one ccm cluster (1 Publisher, 1 subscriber) 5.04 Release.
When I powered off the first CM, as disaster recovery trial, I noted 2 cluster issues:
a) all xml services (extension mobility and 3 ldap query on the corporate directory developed with sdk) were not available om the phones (the cm ip address is in the url of all phone services in Enterprise parameters)
b) the inbound calls from Pstn needed of a lot of time before ringing (I think that the router h323 searched always the first CM, and only after ten seconds, the second).
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.