Le planificateur de flux d'air plante lorsque nous déclenchons le DAG à partir du serveur Web Airflow

Le processus du planificateur de flux d'air se bloque si nous commençons à activer le DAG et le DAG de déclenchement à partir du serveur Web Airflow.

Version Airflow - ** v1.10.4

Serveur Redis v = 5.0.7

exécuteur = CeleryExecutor

scheduler_job.py:1325} ERROR - Exception when executing execute_helper
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/airflow/jobs/scheduler_job.py", line 1323, in _execute
    self._execute_helper()
  File "/usr/lib/python2.7/site-packages/airflow/jobs/scheduler_job.py", line 1412, in _execute_helper
    self.executor.heartbeat()
  File "/usr/lib/python2.7/site-packages/airflow/executors/base_executor.py", line 132, in heartbeat
    self.trigger_tasks(open_slots)
  File "/usr/lib/python2.7/site-packages/airflow/executors/celery_executor.py", line 203, in trigger_tasks
    cached_celery_backend = tasks[0].backend
  File "/usr/lib/python2.7/site-packages/celery/local.py", line 146, in __getattr__
    return getattr(self._get_current_object(), name)
  File "/usr/lib/python2.7/site-packages/celery/app/task.py", line 1037, in backend
    return self.app.backend
  File "/usr/lib/python2.7/site-packages/kombu/utils/objects.py", line 44, in __get__
    value = obj.__dict__[self.__name__] = self.__get(obj)
  File "/usr/lib/python2.7/site-packages/celery/app/base.py", line 1223, in backend
    return self._get_backend()
  File "/usr/lib/python2.7/site-packages/celery/app/base.py", line 940, in _get_backend
    self.loader)
  File "/usr/lib/python2.7/site-packages/celery/app/backends.py", line 74, in by_url
    return by_name(backend, loader), url
  File "/usr/lib/python2.7/site-packages/celery/app/backends.py", line 54, in by_name
    cls = symbol_by_name(backend, aliases)
  File "/usr/lib/python2.7/site-packages/kombu/utils/imports.py", line 57, in symbol_by_name
    module = imp(module_name, package=package, **kwargs)
  File "/usr/lib64/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
ImportError: No module named 'db

Se bloque avec le message d'erreur ci-dessous.

broker_url = 'redis://:password@redis-host:2287/0'
sql_alchemy_conn = postgresql+psycopg2://user:password@host/dbname

result_backend = 'db+postgresql://user:password@host/dbname'

Pourquoi le planificateur plante-t-il lorsque le DAG est déclenché? J'ai essayé d'exécuter pip install DB mais cela n'a pas résolu le problème.