[AIRFLOW-XXXX] Adjust celery defaults to work with breeze

airflow/config_templates/config.yml

@@ -990,7 +990,7 @@
       version_added: ~
       type: string
       example: ~
-      default: "16"
+      default: "8"
     - name: worker_autoscale
       description: |
         The maximum and minimum concurrency that will be used when starting workers with the
@@ -1023,7 +1023,7 @@
       version_added: ~
       type: string
       example: ~
-      default: "sqla+mysql://airflow:airflow@localhost:3306/airflow"
+      default: "redis://redis:6379/0"
     - name: result_backend
       description: |
         The Celery result_backend. When a job finishes, it needs to update the
@@ -1035,7 +1035,7 @@
       version_added: ~
       type: string
       example: ~
-      default: "db+mysql://airflow:airflow@localhost:3306/airflow"
+      default: "db+postgresql://postgres:airflow@postgres/airflow"
     - name: flower_host
       description: |
         Celery Flower is a sweet UI for Celery. Airflow has a shortcut to start

airflow/config_templates/default_airflow.cfg

@@ -468,7 +468,7 @@ celery_app_name = airflow.executors.celery_executor
 # ``airflow celery worker`` command. This defines the number of task instances that
 # a worker will take, so size up your workers based on the resources on
 # your worker box and the nature of your tasks
-worker_concurrency = 16
+worker_concurrency = 8
 
 # The maximum and minimum concurrency that will be used when starting workers with the
 # ``airflow celery worker`` command (always keep minimum processes, but grow
@@ -490,15 +490,15 @@ worker_log_server_port = 8793
 # a sqlalchemy database. Refer to the Celery documentation for more
 # information.
 # http://docs.celeryproject.org/en/latest/userguide/configuration.html#broker-settings
-broker_url = sqla+mysql://airflow:airflow@localhost:3306/airflow
+broker_url = redis://redis:6379/0
 
 # The Celery result_backend. When a job finishes, it needs to update the
 # metadata of the job. Therefore it will post a message on a message bus,
 # or insert it into a database (depending of the backend)
 # This status is used by the scheduler to update the state of the task
 # The use of a database is highly recommended
 # http://docs.celeryproject.org/en/latest/userguide/configuration.html#task-result-backend-settings
-result_backend = db+mysql://airflow:airflow@localhost:3306/airflow
+result_backend = db+postgresql://postgres:airflow@postgres/airflow
 
 # Celery Flower is a sweet UI for Celery. Airflow has a shortcut to start
 # it ``airflow celery flower``. This defines the IP that Celery Flower runs on

airflow/config_templates/default_celery.py

@@ -40,7 +40,7 @@ def _broker_supports_visibility_timeout(url):
         broker_transport_options['visibility_timeout'] = 21600
 
 DEFAULT_CELERY_CONFIG = {
-    'accept_content': ['json', 'pickle'],
+    'accept_content': ['json'],
     'event_serializer': 'json',
     'worker_prefetch_multiplier': 1,
     'task_acks_late': True,