In general many users can share the same instance (these are not the same as OS users). In the NiFi 0.x baseline (HDF 1.2) users can have roles and roles can restrict what users can do. For example, a monitor can get a read only view of the UI and a data flow manager can change anything they want. In NiFi 1.x (HDF 2.0, not yet released) there will be a much finer grained security model where policies can be created for anything on the canvas to give specific users or groups access to an individual component (processor, process-group, etc.). A keytab is a file on the operating system controlled by the standard operating system file permissions. If the NiFi process is running as an operating system user that can access that keytab file, then any NiFi user can go into the UI and create a PutHDFS processor and type in the path to that keytab, because its not based on the user accessing NiFi, its based on the OS user NiFi is running as. The only way I could see preventing this was if files/keytabs could be defined as some kind of first-class resource in NiFi, and then policies could be created to limit which NiFi users could use those resources. ... View more

The boostrap process restarts NiFi when the main NiFi process dies. An easy test is to start a new NiFi and then kill -9 the main process and you'll immediately see it come back with a new pid. OOM would probably be tricky because a lot of times the Java process does not die when encountering an OOM and sticks around in some bad state. ... View more

Currently there aren't any processors that perform direct manipulation of Avro, although we definitely would like to have some. Possible options to work around this... Use ConvertAvroToJson followed by the new JOLT transform processor followed by ConvertJsonToAvro (involves a lot of conversion and may lose some of the initial schema) Use ExecuteScript processor to manipulate the Avro (I am not sure if any of NiFi's supported scripting languages have good Avro support) Write a custom Java processor to manipulate the Avro (https://cwiki.apache.org/confluence/display/NIFI/Maven+Projects+for+Extensions) Happy to help answer any questions if going the custom Java processor route. ... View more

This example uses site-to-site to send logs from one instance to another using a push model: https://github.com/bbende/nifi-streaming-examples The first instance has a Remote Process Group pointing to the URL of the second instance. The second instance has an Input Port to receive logs, which the Remote Process Group from the first instance is connected to. You also need to enable nifi.remote.input.socket.port and nifi.remote.input.secure on the node where the an incoming connection will be made. In this example that is the node with the Input Port which will receive an incoming connection from the Remote Process Group on the first node. ... View more