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Executor

Executors are the mechanism by which :doc:task instances </core-concepts/tasks> get run. They have a common API and are "pluggable", meaning you can swap executors based on your installation needs.

Airflow can only have one executor configured at a time; this is set by the executor option in the [core] section of :doc:the configuration file </howto/set-config>.

Built-in executors are referred to by name, for example:

.. code-block:: ini

[core]
executor = KubernetesExecutor

You can also write your own custom executors, and refer to them by their full path:

.. code-block:: ini

[core]
executor = my_company.executors.MyCustomExecutor

.. note:: For more information on Airflow's configuration, see :doc:/howto/set-config.

If you want to check which executor is currently set, you can use the airflow config get-value core executor command:

.. code-block:: bash

$ airflow config get-value core executor
SequentialExecutor

Executor Types

There are two types of executor - those that run tasks locally (inside the scheduler process), and those that run their tasks remotely (usually via a pool of workers). Airflow comes configured with the SequentialExecutor by default, which is a local executor, and the safest option for execution, but we strongly recommend you change this to LocalExecutor for small, single-machine installations, or one of the remote executors for a multi-machine/cloud installation.

Local Executors

.. toctree:: :maxdepth: 1

debug
local
sequential

Remote Executors

.. toctree:: :maxdepth: 1

celery
celery_kubernetes
dask
kubernetes
local_kubernetes

.. note::

Something that often confuses new users of Airflow is that they don't need to run a separate ``executor`` process. This is because the executor's logic runs *inside* the ``scheduler`` process - if you're running a scheduler, you're running the executor.