PostConfigure and addModule (etc) should support a mode of operation where they do not perform the actual software install and instead assume / verify that the user has already done this (either rpm, deb, or binary + post-install) and purely do the system configuration aspect.
This likely will also help reduce the number of sudo use cases for non root in addition. It will also make it more straightforward to use third party orchestration software such as docker for multi node.
Phase I - user is required to preinstall the software. postConfigure will still communicate with new server for setup.