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Nifi unable to start Cannot set Concurrent Tasks to 0 for component JoltTransformJSON

New Contributor

Hello All,

My nifi instance crashed due to some infra issue and when I restarted it, it gave the following error -

Caused by: java.lang.IllegalArgumentException: Cannot set Concurrent Tasks to 0 for component JoltTransformJSON[id=9d443567-014b-1eab-654a-69ea31a12f53] because Scheduling Strategy is not Event Driven
  at org.apache.nifi.controller.StandardProcessorNode.setMaxConcurrentTasks(

I had to manually edit the flow.xml and flow.json and set concurrentTasks to 1 to bring the docker instance up.

The question is, since NiFi does not allow setting concurrentTasks=0 with CRON_DRIVEN from the UI, how did so many processors end up with that setting.

No one manually interefered with the flow.xml.gz or flow.json.gz
Did anyone else ran into the same issue ?
Any pointers will be helpful

Thank You


New Contributor

I just had the same issue. Had to manually modify the `flow.json.gz` like you did.

Strange that the UI let me set it to 0 in the first place.