In my current scenario; Nifi collects data, then sends to Kafka. Then any streaming engine consumes data from kafka, and analysis it. In this situation; I dont want to use Kafka between Nifi and Streaming Engine. So, I want to send data from Nifi to streaming engine directly. But, I don't know some details here.
For example Spark Structured Streaming; Assumet that I send data from Nifi to Spark Structured Streaming directly, Spark was received this data but then spark's node is down. What happens to data in Spark node? (Do Spark Structured Streaming have any Nifi receiver?), Also, in this case, what is the data guarantee on Spark Structured Streaming?
For example Storm; Storm has Nifi Bolt. But, assume that Storm have received data from Nifi, but then node was down. What happens to the data? Also, in this case, what is the data guarantee on Storm?
In shortly, I want to send data from Nifi to SparkStructuredStreaming/Storm(I'm more likely to used Spark.) directly. But if any node is downs in streaming engine cluster, I dont want to lose data.
Is this possible for Spark Structured Streaming?
All of the streaming integration with NiFi is done using the site-to-site protocol, which is originally made for two NiFi instances to transfer data.
As far as I know there are currently integrations with Storm, Spark streaming, and Flink. I'm not familiar with Spark structured streaming, but I would imagine you could build this integration similar to the others.
https://github.com/apache/nifi/tree/master/nifi-external/nifi-spark-receiver
https://github.com/apache/nifi/tree/master/nifi-external/nifi-storm-spout
https://github.com/apache/flink/tree/master/flink-connectors/flink-connector-nifi
NiFi is not a replayable source of data though. The data is transferred from NiFi to the streaming system in a transaction to ensure it is not removed from the NiFi side until the destination has confirmed the transaction. However, if something fails in the streaming system after that commit, then the data is no longer in NiFi and it is the streaming system's problem.
I'm not sure the reason why you don't want to use Kafka, but NiFi -> Kafka -> Streaming is a more standard and proven approach.