There are 2 configuration files which provides nifi for a lot of config values.
The nifi system does not provides an easy way to override the values in these config files.
Generally the applications are designed in a way to override or use configs from environment values and config-files
It may be that this was not such a big problem when running Nifi on baremetals and managing a machine as an independent machine. However, when one thinks of automating or scripting these operator functions of start/shutdown nodes, add/remove nodes, change configuration values, then it becomes difficult for an operator to manage files on all nodes.
I am looking ahead to Nifi to add some way to read these values from environment variables or config-files.