You can be 100% that one forked flow file will not effect another. When a flow file is passed from one processor to another, the upstream processor passes a reference (to flowfile in content repository) to the second processor. When one processor forks the same flow file to two different processors, the flow file in content repository is CLONED ... reference of one clone is passed to one processor and reference to the other clone is passed to the second processor. Note that viewing the provenance of your flow live flow shows these reference-clone details. This explains flowfile life cycle, including explanation here: https://nifi.apache.org/docs/nifi-docs/html/nifi-in-depth.html#pass-by-reference ... View more

Unfortunately not every property currently supports using the variable registry. The way you can tell is in the documentation for a processor, by looking at the property description. If it says "Supports Expression Language: true" then you can reference variables. For example, with PutHDFS it looks like only the Directory property currently supports it: https://nifi.apache.org/docs/nifi-docs/components/org.apache.nifi.processors.hadoop.PutHDFS/index.html ... View more

Since NiFi 1.0, there are two types of controller services... You can create controller services from the global hamburger menu in the top right, but these are only to be used by any reporting tasks that use a controller service. For example, the site to site provenance reporting task can use an SSL context service. For processors they have to be created through the context pallet on the left hand side. If you are on the root canvas and have nothing selected, and then click the configuration icon in the pallet then you can create a controller service at the root group. These should be visible to any processors on the root group and with in any sub groups. If you go into a process group and create a controller service there, then it is visible to anything in that group and below, but not anything above it. ... View more

I realized PutHiveQL supports parameterized Hive query and I went for that. ... View more

I realized PutHiveQL supports parameterized Hive query and I went for that. ... View more

There is both a push (reporting api) and pull (restful api) way to automate metrics collection in NiFI. See this post for an overview: https://community.hortonworks.com/questions/69004/nifi-monitoring-processor-and-nifi-service.html ... View more