Occasionally, tasks fail or may fail to execute in the batch-ingest Airflow application. Tasks can fail for a variety of reasons that are unrelated to the nature of the data being processed. In such cases –such as when a networking error causes a task to fail– you can often troubleshoot the issue by "clearing" a task, causing it to restart.

How to clear a task

The first step to clearing tasks in Airflow is to identify them. The second step is then to clear the task (which may, in turn, automatically clear its downstream tasks).

Clear tasks with the DAG "Details" tab

One method to clear failed or zombie tasks is to use the "details" tab in the DAG overview page.

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Airflow should immediately prepare to run the queued tasks. You can check on the status of Airflow's progress from the Airflow Admin UI main page.

Tasks are running again.

Clear tasks with the DAG "Tree view"

Another method to clear tasks is to use the tree view DAG overview page.

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