It is typical for applications to allow plugins/co-processors that are essentially a set of additional jar files in the classpath and optionally a set of config files or config changes.
Current, slider app packages can handle additional config changes/entries very well. Additional configs files can be added as well but it is not easy if the config files include parameters that need to be resolved by the agent. This requires app package changes. Dropping additional jar files into the class path is not easy and requires app package changes.
It is not efficient to modify the app package to support such plugins. App packaging and create command should be modified such that the user can dynamically specify additional jars, config files, configs etc.
Specific scenarios are modifying HBase to add support for Phoenix or Ranger.