Setting Configuration Options

The first time you run Airflow, it will create a file called airflow.cfg in your $AIRFLOW_HOME directory (~/airflow by default). This file contains Airflow’s configuration and you can edit it to change any of the settings. You can also set options with environment variables by using this format: $AIRFLOW__{SECTION}__{KEY} (note the double underscores).

For example, the metadata database connection string can either be set in airflow.cfg like this:

sql_alchemy_conn = my_conn_string

or by creating a corresponding environment variable:

export AIRFLOW__CORE__SQL_ALCHEMY_CONN=my_conn_string

You can also derive the connection string at run time by appending _cmd to the key like this:

sql_alchemy_conn_cmd = bash_command_to_run

The following config options support this _cmd version:

  • sql_alchemy_conn in [core] section

  • fernet_key in [core] section

  • broker_url in [celery] section

  • flower_basic_auth in [celery] section

  • result_backend in [celery] section

  • password in [atlas] section

  • smtp_password in [smtp] section

  • bind_password in [ldap] section

  • git_password in [kubernetes] section

The _cmd config options can also be set using a corresponding environment variable the same way the usual config options can. For example:

export AIRFLOW__CORE__SQL_ALCHEMY_CONN_CMD=bash_command_to_run

The idea behind this is to not store passwords on boxes in plain text files.

The universal order of precedence for all configuration options is as follows:

  1. set as an environment variable

  2. set as a command environment variable

  3. set in airflow.cfg

  4. command in airflow.cfg

  5. Airflow’s built in defaults

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