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Using Apache Airflow configuration options on Amazon MWAA

Apache Airflow configuration options can be attached to your Amazon Managed Workflows for Apache Airflow environment as environment variables. You can choose from the suggested dropdown list, or specify custom configuration options for your Apache Airflow version on the Amazon MWAA console. This topic describes the Apache Airflow configuration options available, and how to use these options to override Apache Airflow configuration settings on your environment.

Prerequisites

You'll need the following before you can complete the steps on this page.

How it works

When you create an environment, Amazon MWAA attaches the configuration settings you specify on the Amazon MWAA console in Airflow configuration options as environment variables to the Amazon Fargate container for your environment. If you're using a setting of the same name in airflow.cfg, the options you specify on the Amazon MWAA console override the values in airflow.cfg.

While we don't expose the airflow.cfg in the Apache Airflow UI of an Amazon MWAA environment by default, you can change the Apache Airflow configuration options directly on the Amazon MWAA console, including setting webserver.expose_config to expose the configurations.

Using configuration options to load plugins in Apache Airflow v2

By default in Apache Airflow v2, plugins are configured to be "lazily" loaded using the core.lazy_load_plugins : True setting. If you're using custom plugins in Apache Airflow v2, you must add core.lazy_load_plugins : False as an Apache Airflow configuration option to load plugins at the start of each Airflow process to override the default setting.

Configuration options overview

When you add a configuration on the Amazon MWAA console, Amazon MWAA writes the configuration as an environment variable.

Apache Airflow configuration options

The following image shows where you can customize the Apache Airflow configuration options on the Amazon MWAA console.

Apache Airflow reference

For a list of configuration options supported by Apache Airflow, see Configuration Reference in the Apache Airflow reference guide. To view the options for the version of Apache Airflow you are running on Amazon MWAA, select the version from the drop down list.

Using the Amazon MWAA console

The following procedure walks you through the steps of adding an Airflow configuration option to your environment.

Configuration reference

The following section contains the list of available Apache Airflow configurations in the dropdown list on the Amazon MWAA console.

Email configurations

The following list shows the Airflow email notification configuration options available on Amazon MWAA.

We recommend using port 587 for SMTP traffic. By default, Amazon blocks outbound SMTP traffic on port 25 of all Amazon EC2 instances. If you want to send outbound traffic on port 25, you can request for this restriction to be removed.

Apache Airflow v2

Airflow version	Airflow configuration option	Description	Example value
v2	email.email_backend	The Apache Airflow utility used for email notifications in email_backend.	airflow.utils.email.send_email_smtp
v2	smtp.smtp_host	The name of the outbound server used for the email address in smtp_host.	localhost
v2	smtp.smtp_starttls	Transport Layer Security (TLS) is used to encrypt the email over the Internet in smtp_starttls.	False
v2	smtp.smtp_ssl	Secure Sockets Layer (SSL) is used to connect the server and email client in smtp_ssl.	True
v2	smtp.smtp_port	The Transmission Control Protocol (TCP) port designated to the server in smtp_port.	587
v2	smtp.smtp_mail_from	The outbound email address in smtp_mail_from.	myemail@domain.com

Task configurations

The following list shows the configurations available in the dropdown list for Airflow tasks on Amazon MWAA.

Apache Airflow v2

Airflow version	Airflow configuration option	Description	Example value
v2	core.default_task_retries	The number of times to retry an Apache Airflow task in default_task_retries.	3
v2	core.parallelism	The maximum number of task instances that can run simultaneously across the entire environment in parallel (parallelism).	40

Scheduler configurations

The following list shows the Apache Airflow scheduler configurations available in the dropdown list on Amazon MWAA.

Apache Airflow v2

Airflow version	Airflow configuration option	Description	Example value
v2	scheduler.catchup_by_default	Tells the scheduler to create a DAG run to "catch up" to the specific time interval in catchup_by_default.	False
v2	scheduler.scheduler_zombie_task_threshold	Tells the scheduler whether to mark the task instance as failed and reschedule the task in scheduler_zombie_task_threshold.	300

Worker configurations

The following list shows the Airflow worker configurations available in the dropdown list on Amazon MWAA.

Apache Airflow v2

Airflow version	Airflow configuration option	Description	Example value
v2	celery.worker_autoscale	The maximum and minimum number of tasks that can run concurrently on any worker using the Celery Executor in worker_autoscale. Value must be comma-separated in the following order: max_concurrency,min_concurrency.	16,12

Web server configurations

The following list shows the Airflow web server configurations available in the dropdown list on Amazon MWAA.

Apache Airflow v2

Airflow version	Airflow configuration option	Description	Example value
v2	webserver.default_ui_timezone	The default Apache Airflow UI datetime setting in default_ui_timezone. Note Setting the default_ui_timezone option does not change the time zone in which your DAGs are scheduled to run. To change the time zone for your DAGs, you can use a custom plugin. For more information, see Changing a DAG's timezone on Amazon MWAA.	America/New_York

Triggerer configurations

The following list shows the Apache Airflow triggerer configurations available on Amazon MWAA.

Apache Airflow v2

Airflow version	Airflow configuration option	Description	Example value
v2.7	mwaa.triggerer_enabled	Used for activating and deactivating the triggerer on Amazon MWAA. By default, this value is set to True. If set to False, Amazon MWAA will not start any triggerer processes on schedulers.	True
v2.7	triggerer.default_capacity	Defines the number triggers each triggerer can run in parallel. On Amazon MWAA, this capacity is set per each triggerer and per each scheduler as both components run alongside each other. The default per scheduler is set to 60, 125, 250, 500, and 1000 for small, medium and large, xlarge, and 2xlarge instances, respectively.	125

Examples and sample code

Example DAG

You can use the following DAG to print your email_backend Apache Airflow configuration options. To run in response to Amazon MWAA events, copy the code to your environment's DAGs folder on your Amazon S3 storage bucket.

from airflow.decorators import dag
from datetime import datetime

def print_var(**kwargs):
  email_backend = kwargs['conf'].get(section='email', key='email_backend')
  print("email_backend")
  return email_backend
  
@dag(
  dag_id="print_env_variable_example",
  schedule_interval=None,     
  start_date=datetime(yyyy, m, d),
  catchup=False,
)
def print_variable_dag():
  email_backend_test = PythonOperator(
  task_id="email_backend_test",
  python_callable=print_var,
  provide_context=True
)
  
print_variable_test = print_variable_dag()

Example email notification settings

The following Apache Airflow configuration options can be used for a Gmail.com email account using an app password. For more information, see Sign in using app passwords in the Gmail Help reference guide.

What's next?