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 the start a test session link in the banner on top of the Canvas.


  2. Review the suggested NiFi configuration. You do not need to change anything.


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

    Active Test Session    .
    This can take several minutes.
  5. Go to Flow Options > Services to enable Controller Services.
  6. Select a service you want to enable, then click the Enable Service and Referencing Components icon.
    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 the Filter Edits, Route on Content Size, and Merge Edit Events processors as well.
    Repeat this step for all Controller Services.
  7. Click the Flow Designer link in the breadcrumbs on the top of the page to return to the Flow Design canvas.
  8. Start the remaining inactive processors.
    1. Start the Get Recent Wikipedia Changes processor by selecting it on the canvas, then clicking the [Start] icon in the component details pane.
    2. Start the Write "Added Content" Events To File processor by selecting it on the canvas, then clicking the [Start] icon in the component details pane.
    3. Start the Write "Removed Content" Events To File processor by selecting it on the canvas, then clicking the [Start] icon in the component details pane.


    All other components were auto-started when you selected the Enable Service and Referencing Components option in the Flow Options > Services view.
  9. Observe your first draft flow processing data.
    On the Flow Designer 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.