I found this point before, there is only one of them in full service. I tried to restart the service on another one. when the second node in full service it will bring the first node down. I guess in HA, it may only have one active ccx engineer.
No, that's not how it works. Both nodes should be up and fully active; each one the assumes either 'master' or 'secondary' status. If you are new to this product you should spend some time reading the documentation to get familiarity with the basics before working with it.
If either node is not active, you cannot make configuration changes.
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.