Cloudera Docs

Start a test session

To validate your draft, start a test session. This provisions an Apache NiFi cluster where you can test your draft.

Starting a Test Session provisions NiFi resources, acting like a development sandbox for a particular draft. It allows you to work with live data to validate your data flow logic while updating your draft. You can suspend a test session any time and change the configuration of the NiFi cluster then resume testing with the updated configuration.
  1. Click start a test session in the banner on top of the Canvas.


  2. Click Start Test Session.
    Test Session status Initializing Test Session... appears on top of the page.
  3. Wait for the status to change to

    Active Test Session    .
    This may take several minutes.
  4. Click Flow Options > Services to enable Controller Services.
  5. Select a service you want to enable, then click Enable Service and Referencing Components.
    This option does not only enable the controller service, but also any component that references it. This way, you do not need to enable the component separately to run the test session. In the context of this tutorial, enabling the 'AvroReader_Recent_Changes' controller service will also enable 'Filter Edits', 'Route on Content Size', and 'Merge Edit Events' processors as well.
    Repeat this step for all Controller Services.
  6. Click Back To Flow Designer to return to the flow design Canvas.
  7. Start the Get Recent Wikipedia Changes, Write "Added Content" Events To File, and Write "Removed Content" Events To File components by selecting them on the Canvas then clicking Start.
    All other components were auto-started when you selected the Enable Service and Referencing Components option.
  8. Observe your first draft flow processing data.
    On the Flow Design Canvas you can observe statistics on your processors change as they consume and process data from Wikipedia. You can also observe one or more blue Notification Pills, providing information about the current task.