Unless Architecture;
NiFi execute in the JVM host operating system. The main components of the JVM NiFi follows:
Web Server：
Purpose is to carry NiFi web server based HTTP-based command and control API.
Flow Controller
The flow controller is the brains of the operation. It provides threads for extensions to run on, and manages the schedule of when extensions receive resources to execute.
Brain flow controller operation. It provides a thread can run on it to expand and manage resource scheduling the time of receiving the extension to be executed.
Extensions
It describes various types of NiFi expansion in other documents. The key here is to expand the operation and implementation of the JVM.
FlowFile Repository：
The FlowFile Repository is where NiFi keeps track of the state of what it knows about a given FlowFile that is presently active in the flow. The implementation of the repository is pluggable. The default approach is a persistent Write-Ahead Log located on a specified disk partition.。
Content Repository：
The Content Repository is where the actual content bytes of a given FlowFile live. The implementation of the repository is pluggable. The default approach is a fairly simple mechanism, which stores blocks of data in the file system. More than one file system storage location can be specified so as to get different physical partitions engaged to reduce contention on any single volume.
Provenance Repository：
The Provenance Repository is where all provenance event data is stored. The repository construct is pluggable with the default implementation being to use one or more physical disk volumes. Within each location event data is indexed and searchable.
