How to update variable.registry.properties in Nifi on the fly?

Question

The variable registry properties is a functionality that was added to Nifi in order to promote software developement life cycle. Meaning that you can develop your flows in a separate developement environement and take advantage of the custom properties files specified in the nifi.variable.registry.properties property alongside with expression language to use variables in the processors configurations. Then you can export your flows as templates together with your custom properties files and push them to a production environement. However once the production instance of Nifi is started it is not possible to modify your custom properties files. This means that if you want to add a second flow to your production, you need to stop the instance, update the custom properties files and upload the second flow's template, and then restart the server. This makes custom properties files more like instance (nifi instance) related and not flow related. My question is thus, is there a way to update custom properties files on the fly without having to restart Nifi each time you want to add a new flow ?

Hope my question is clear, don't hesitate to ask for clarification

Answer 1

The current variable registry capability requires a restart and cannot be updated on the fly.

The community has plans to build out more advanced variable registry capabilities, as well as capabilities around versioning/deploying of flows, which both tie together as you mentioned.

Some relevant information for future design ideas is captured in these wiki pages:

https://cwiki.apache.org/confluence/display/NIFI/Variable+Registry https://cwiki.apache.org/confluence/display/NIFI/Configuration+Management+of+Flows

Feel free to join in the discussion by providing comments on the wiki page, or shooting a note to [email protected], we would love to capture all feedback.