Default args and DAG parameters in Apache Airflow - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of default_args in an Airflow DAG?

default_args is a dictionary used to set default parameters for all tasks in a DAG. It helps avoid repeating common settings like retries, start date, or email notifications.

beginner

Name three common parameters you might include in default_args.

Common parameters include start_date, retries, and retry_delay. These control when the DAG starts, how many times to retry a failed task, and the wait time between retries.

intermediate

How do DAG parameters differ from default_args?

DAG parameters are settings that define the DAG itself, like its schedule_interval or description. default_args apply to tasks inside the DAG, setting defaults for task behavior.

intermediate

What happens if you set a start_date in default_args that is in the future?

The DAG will not run until the start_date is reached. Airflow schedules tasks only after this date, so no runs happen before it.

intermediate

How can you override a default_args parameter for a specific task?

You can pass the parameter directly when creating the task. For example, if retries is 3 in default_args, you can set retries=1 in the task to override it.

What is the role of default_args in an Airflow DAG?

A Create new tasks dynamically

B Define the DAG's schedule interval

C Set default parameters for all tasks in the DAG

D Store logs of task runs

default_args sets default task parameters like retries and start date, applying to all tasks unless overridden.

Which parameter in default_args controls how many times a task retries on failure?

A retry_delay

B retries

C start_date

D schedule_interval

retries defines how many retry attempts a task will make if it fails.

If you want a DAG to run every day at midnight, which DAG parameter should you set?

A default_args

B retries

C start_date

D schedule_interval

schedule_interval controls how often the DAG runs, such as daily at midnight.

What happens if a task does not have a parameter set in default_args or in the task itself?

A Airflow uses a global default value

B The task will fail immediately

C The DAG will not start

D The parameter is ignored

Airflow uses built-in global defaults if no value is provided in default_args or the task.

How can you specify a different retry delay for a single task than the one in default_args?

A Set <code>retry_delay</code> when defining the task

B Change <code>retry_delay</code> in <code>default_args</code>

C Modify the DAG's <code>schedule_interval</code>

D You cannot override it per task

You can override retry_delay by passing it directly when creating the task.

Explain what default_args is and why it is useful in Airflow DAGs.

Think about how to set common settings for many tasks at once.

Describe the difference between DAG parameters and default_args in Airflow.

One controls the whole workflow, the other controls tasks inside it.