There is a new Cloudera release of Apache NiFi now with SAML support.
Apache NiFi 126.96.36.199.1.1.0
Apache NiFi Registry 0.8.0.2.1.1.0
Get your download on: https://docs.cloudera.com/cfm/2.1.1/download/topics/cfm-download-locations.html
To start researching for the future, take a look at some of the technical preview features around Easy Rules engine and handlers.
Make sure you use the latest possible JDK 8 as there are some bugs out there. Use a recent version of the JDK like 8u282 or newer.
Size your cluster correctly! https://docs.cloudera.com/cfm/2.1.1/nifi-sizing/topics/cfm-sizing-recommendations.html. Make sure you have at least 3 nodes.