[jira] [Comment Edited] (AIRFLOW-6518) Task did not retry when there was temporary metastore db connectivity loss

[t oo (Jira)]

    [ 
https://issues.apache.org/jira/browse/AIRFLOW-6518?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17016625#comment-17016625
 ] 

t oo edited comment on AIRFLOW-6518 at 1/16/20 7:27 AM:
--------------------------------------------------------

some options:
1. introduce db retry config - https://stackoverflow.com/a/53300049/8874837
2. set conservative defaults, wrap calls to db functions in try/catch with 
sleep and another call to the db function
ie 
https://github.com/apache/airflow/blob/1.10.6/airflow/models/taskinstance.py#L961-L969
{code}
        except AirflowException as e:
            self.refresh_from_db()
            # for case when task is marked as success/failed externally
            # current behavior doesn't hit the success callback
            if self.state in {State.SUCCESS, State.FAILED}:
                return
            else:
                self.handle_failure(e, test_mode, context)
                raise
{code}
CHANGES TO
{code}
        except AirflowException as e:
          try:
              self.refresh_from_db()
              # for case when task is marked as success/failed externally
              # current behavior doesn't hit the success callback
              if self.state in {State.SUCCESS, State.FAILED}:
                  return
              else:
                  self.handle_failure(e, test_mode, context)
                  raise
          except (Exception, KeyboardInterrupt) as e:
              sleep(5)
              self.refresh_from_db()
              # for case when task is marked as success/failed externally
              # current behavior doesn't hit the success callback
              if self.state in {State.SUCCESS, State.FAILED}:
                  return
              else:
                  self.handle_failure(e, test_mode, context)
                  raise
{code}
3. make the db function have try/catch with sleep and repeat
ie in refresh_from_db() of models/taskinstance.py
{code}
        TI = TaskInstance

        qry = session.query(TI).filter(
            TI.dag_id == self.dag_id,
            TI.task_id == self.task_id,
            TI.execution_date == self.execution_date)

        if lock_for_update:
            ti = qry.with_for_update().first()
        else:
            ti = qry.first()
{code}
CHANGES TO
{code}
try:
        TI = TaskInstance

        qry = session.query(TI).filter(
            TI.dag_id == self.dag_id,
            TI.task_id == self.task_id,
            TI.execution_date == self.execution_date)

        if lock_for_update:
            ti = qry.with_for_update().first()
        else:
            ti = qry.first()
except:
       sleep(5)
        TI = TaskInstance
        qry = session.query(TI).filter(
            TI.dag_id == self.dag_id,
            TI.task_id == self.task_id,
            TI.execution_date == self.execution_date)

        if lock_for_update:
            ti = qry.with_for_update().first()
        else:
            ti = qry.first()
{code}


was (Author: toopt4):
some options:
1. introduce db retry config - https://stackoverflow.com/a/53300049/8874837
2. set conservative defaults, wrap calls to db functions in try/catch with 
sleep and another call to the db function
ie 
https://github.com/apache/airflow/blob/1.10.6/airflow/models/taskinstance.py#L961-L969
{code}
        except AirflowException as e:
            self.refresh_from_db()
            # for case when task is marked as success/failed externally
            # current behavior doesn't hit the success callback
            if self.state in {State.SUCCESS, State.FAILED}:
                return
            else:
                self.handle_failure(e, test_mode, context)
                raise
{code}
CHANGES TO
{code}
        except AirflowException as e:
          try:
              self.refresh_from_db()
              # for case when task is marked as success/failed externally
              # current behavior doesn't hit the success callback
              if self.state in {State.SUCCESS, State.FAILED}:
                  return
              else:
                  self.handle_failure(e, test_mode, context)
                  raise
          except (Exception, KeyboardInterrupt) as e:
              sleep(5)
              self.refresh_from_db()
              # for case when task is marked as success/failed externally
              # current behavior doesn't hit the success callback
              if self.state in {State.SUCCESS, State.FAILED}:
                  return
              else:
                  self.handle_failure(e, test_mode, context)
                  raise
{code}
3. make the db function have try/catch with sleep and repeat

> Task did not retry when there was temporary metastore db connectivity loss
> --------------------------------------------------------------------------
>
>                 Key: AIRFLOW-6518
>                 URL: https://issues.apache.org/jira/browse/AIRFLOW-6518
>             Project: Apache Airflow
>          Issue Type: Bug
>          Components: database, scheduler
>    Affects Versions: 1.10.6
>            Reporter: t oo
>            Priority: Major
>
> My DAG has got retries configured at the task level. I started a dagrun, then 
> while a task was running the metastore db crashed, the task failed, but the 
> dagrun did not attempt to retry the task (even though task retries are 
> configured!), db recovered 3 seconds after the task failed, instead the 
> dagrun went to FAILED state.
> *Last part of log of TaskInstance:*
> [2020-01-08 17:34:46,301] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk Traceback (most recent call last):
> [2020-01-08 17:34:46,301] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File "/home/ec2-user/venv/bin/airflow", line 37, in <module>
> [2020-01-08 17:34:46,302] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     args.func(args)
> [2020-01-08 17:34:46,302] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/cli.py", 
> line 74, in wrapper
> [2020-01-08 17:34:46,302] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     return f(*args, **kwargs)
> [2020-01-08 17:34:46,302] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 551, in run
> [2020-01-08 17:34:46,302] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     _run(args, dag, ti)
> [2020-01-08 17:34:46,302] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 469, in _run
> [2020-01-08 17:34:46,302] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     pool=args.pool,
> [2020-01-08 17:34:46,302] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/db.py", 
> line 74, in wrapper
> [2020-01-08 17:34:46,302] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     return func(*args, **kwargs)
> [2020-01-08 17:34:46,302] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/models/taskinstance.py",
>  line 962, in _run_raw_task
> [2020-01-08 17:34:46,302] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     self.refresh_from_db()
> [2020-01-08 17:34:46,303] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/db.py", 
> line 74, in wrapper
> [2020-01-08 17:34:46,303] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     return func(*args, **kwargs)
> [2020-01-08 17:34:46,303] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/models/taskinstance.py",
>  line 461, in refresh_from_db
> [2020-01-08 17:34:46,303] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     ti = qry.first()
> [2020-01-08 17:34:46,303] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3265, in first
> [2020-01-08 17:34:46,303] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     ret = list(self[0:1])
> [2020-01-08 17:34:46,303] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3043, in __getitem__
> [2020-01-08 17:34:46,303] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     return list(res)
> [2020-01-08 17:34:46,303] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3367, in __iter__
> [2020-01-08 17:34:46,303] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     return self._execute_and_instances(context)
> [2020-01-08 17:34:46,304] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3389, in _execute_and_instances
> [2020-01-08 17:34:46,304] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     querycontext, self._connection_from_session, close_with_result=True
> [2020-01-08 17:34:46,304] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3404, in _get_bind_args
> [2020-01-08 17:34:46,304] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     mapper=self._bind_mapper(), clause=querycontext.statement, **kw
> [2020-01-08 17:34:46,304] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3382, in _connection_from_session
> [2020-01-08 17:34:46,305] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     conn = self.session.connection(**kw)
> [2020-01-08 17:34:46,305] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1133, in connection
> [2020-01-08 17:34:46,305] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     execution_options=execution_options,
> [2020-01-08 17:34:46,305] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1139, in _connection_for_bind
> [2020-01-08 17:34:46,305] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     engine, execution_options
> [2020-01-08 17:34:46,305] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 432, in _connection_for_bind
> [2020-01-08 17:34:46,305] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     conn = bind._contextual_connect()
> [2020-01-08 17:34:46,305] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2242, in _contextual_connect
> [2020-01-08 17:34:46,305] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     self._wrap_pool_connect(self.pool.connect, None),
> [2020-01-08 17:34:46,306] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2280, in _wrap_pool_connect
> [2020-01-08 17:34:46,306] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     e, dialect, self
> [2020-01-08 17:34:46,306] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 1547, in _handle_dbapi_exception_noconnection
> [2020-01-08 17:34:46,306] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     util.raise_from_cause(sqlalchemy_exception, exc_info)
> [2020-01-08 17:34:46,306] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/util/compat.py",
>  line 398, in raise_from_cause
> [2020-01-08 17:34:46,306] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     reraise(type(exception), exception, tb=exc_tb, cause=cause)
> [2020-01-08 17:34:46,306] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2276, in _wrap_pool_connect
> [2020-01-08 17:34:46,306] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     return fn()
> [2020-01-08 17:34:46,306] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 363, in connect
> [2020-01-08 17:34:46,306] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     return _ConnectionFairy._checkout(self)
> [2020-01-08 17:34:46,307] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 760, in _checkout
> [2020-01-08 17:34:46,307] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     fairy = _ConnectionRecord.checkout(pool)
> [2020-01-08 17:34:46,307] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 492, in checkout
> [2020-01-08 17:34:46,307] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     rec = pool._do_get()
> [2020-01-08 17:34:46,307] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/impl.py",
>  line 238, in _do_get
> [2020-01-08 17:34:46,307] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     return self._create_connection()
> [2020-01-08 17:34:46,307] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 308, in _create_connection
> [2020-01-08 17:34:46,307] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     return _ConnectionRecord(self)
> [2020-01-08 17:34:46,308] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 437, in __init__
> [2020-01-08 17:34:46,308] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     self.__connect(first_connect_check=True)
> [2020-01-08 17:34:46,308] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 639, in __connect
> [2020-01-08 17:34:46,308] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     connection = pool._invoke_creator(self)
> [2020-01-08 17:34:46,308] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/strategies.py",
>  line 114, in connect
> [2020-01-08 17:34:46,308] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     return dialect.connect(*cargs, **cparams)
> [2020-01-08 17:34:46,309] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/default.py",
>  line 482, in connect
> [2020-01-08 17:34:46,309] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     return self.dbapi.connect(*cargs, **cparams)
> [2020-01-08 17:34:46,309] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/__init__.py",
>  line 84, in Connect
> [2020-01-08 17:34:46,309] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     return Connection(*args, **kwargs)
> [2020-01-08 17:34:46,309] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/connections.py",
>  line 179, in __init__
> [2020-01-08 17:34:46,309] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk     super(Connection, self).__init__(*args, **kwargs2)
> [2020-01-08 17:34:46,310] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError) 
> (2005, "Unknown MySQL server host 'redacted_dbhosthere' (11)")
> [2020-01-08 17:34:46,310] {base_task_runner.py:115} INFO - Job 34662: Subtask 
> mytsk (Background on this error at: http://sqlalche.me/e/e3q8)
> [2020-01-08 17:34:48,721] {logging_mixin.py:112} INFO - [2020-01-08 
> 17:34:48,721] {local_task_job.py:78} ERROR - Received SIGTERM. Terminating 
> subprocesses
> [2020-01-08 17:34:48,837] {helpers.py:308} INFO - Sending 15 to GPID 20566
> [2020-01-08 17:34:48,837] {helpers.py:286} INFO - Process 
> psutil.Process(pid=20566, status='terminated') (20566) terminated with exit 
> code 1
> *Part of scheduler logs:*
> [2020-01-08 17:34:48,818] {scheduler_job.py:1367} INFO - Exited execute loop
> Traceback (most recent call last):
>   File "/home/ec2-user/venv/bin/airflow", line 37, in <module>
>     args.func(args)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/cli.py", 
> line 74, in wrapper
>     return f(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 551, in run
>     _run(args, dag, ti)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 464, in _run
>     run_job.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/jobs/base_job.py",
>  line 233, in run
>     session.merge(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2113, in merge
> Traceback (most recent call last):
>   File "/home/ec2-user/venv/bin/airflow", line 37, in <module>
>     args.func(args)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/cli.py", 
> line 74, in wrapper
>     return f(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 551, in run
>     _run(args, dag, ti)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 464, in _run
>     run_job.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/jobs/base_job.py",
>  line 233, in run
>     session.merge(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2113, in merge
>     _resolve_conflict_map=_resolve_conflict_map,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2186, in _merge
>     merged = self.query(mapper.class_).get(key[1])
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 982, in get
>     _resolve_conflict_map=_resolve_conflict_map,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2186, in _merge
>     merged = self.query(mapper.class_).get(key[1])
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 982, in get
>     return self._get_impl(ident, loading.load_on_pk_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 1094, in _get_impl
>     return db_load_fn(self, primary_key_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/loading.py",
>  line 284, in load_on_pk_identity
>     return q.one()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3325, in one
>     ret = self.one_or_none()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3294, in one_or_none
>     ret = list(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3367, in __iter__
>     return self._execute_and_instances(context)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3389, in _execute_and_instances
>     querycontext, self._connection_from_session, close_with_result=True
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3404, in _get_bind_args
> Traceback (most recent call last):
>   File "/home/ec2-user/venv/bin/airflow", line 37, in <module>
>     args.func(args)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/cli.py", 
> line 74, in wrapper
>     return f(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 551, in run
>     _run(args, dag, ti)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 464, in _run
>     run_job.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/jobs/base_job.py",
>  line 233, in run
>     mapper=self._bind_mapper(), clause=querycontext.statement, **kw
>       File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3382, in _connection_from_session
> session.merge(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2113, in merge
>     _resolve_conflict_map=_resolve_conflict_map,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2186, in _merge
>     conn = self.session.connection(**kw)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1133, in connection
>     merged = self.query(mapper.class_).get(key[1])
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 982, in get
>     execution_options=execution_options,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1139, in _connection_for_bind
>     return self._get_impl(ident, loading.load_on_pk_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 1094, in _get_impl
>     engine, execution_options
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 432, in _connection_for_bind
>     return db_load_fn(self, primary_key_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/loading.py",
>  line 284, in load_on_pk_identity
>     return q.one()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3325, in one
>     ret = self.one_or_none()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3294, in one_or_none
>     ret = list(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3367, in __iter__
>     return self._execute_and_instances(context)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3389, in _execute_and_instances
>     querycontext, self._connection_from_session, close_with_result=True
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3404, in _get_bind_args
>     mapper=self._bind_mapper(), clause=querycontext.statement, **kw
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3382, in _connection_from_session
>     conn = bind._contextual_connect()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2242, in _contextual_connect
>     conn = self.session.connection(**kw)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1133, in connection
>     self._wrap_pool_connect(self.pool.connect, None),
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2280, in _wrap_pool_connect
>     execution_options=execution_options,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1139, in _connection_for_bind
>     engine, execution_options
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 432, in _connection_for_bind
>     conn = bind._contextual_connect()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2242, in _contextual_connect
>     self._wrap_pool_connect(self.pool.connect, None),
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2280, in _wrap_pool_connect
>     e, dialect, self
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 1547, in _handle_dbapi_exception_noconnection
>     util.raise_from_cause(sqlalchemy_exception, exc_info)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/util/compat.py",
>  line 398, in raise_from_cause
>     reraise(type(exception), exception, tb=exc_tb, cause=cause)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2276, in _wrap_pool_connect
>     return fn()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 363, in connect
>     return _ConnectionFairy._checkout(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 760, in _checkout
>     fairy = _ConnectionRecord.checkout(pool)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 492, in checkout
>     rec = pool._do_get()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/impl.py",
>  line 238, in _do_get
>     return self._create_connection()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 308, in _create_connection
>     return _ConnectionRecord(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 437, in __init__
>     self.__connect(first_connect_check=True)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 639, in __connect
>     connection = pool._invoke_creator(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/strategies.py",
>  line 114, in connect
>     return dialect.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/default.py",
>  line 482, in connect
>     return self.dbapi.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/__init__.py",
>  line 84, in Connect
>     return Connection(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/connections.py",
>  line 179, in __init__
>     super(Connection, self).__init__(*args, **kwargs2)
> sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError) 
> (2005, "Unknown MySQL server host 'redacted_dbhosthere' (11)")
> (Background on this error at: http://sqlalche.me/e/e3q8)
> Traceback (most recent call last):
>   File "/home/ec2-user/venv/bin/airflow", line 37, in <module>
>     args.func(args)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/cli.py", 
> line 74, in wrapper
>     return f(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 551, in run
>     _run(args, dag, ti)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 464, in _run
>     run_job.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/jobs/base_job.py",
>  line 233, in run
>     session.merge(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2113, in merge
>     _resolve_conflict_map=_resolve_conflict_map,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2186, in _merge
>     merged = self.query(mapper.class_).get(key[1])
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 982, in get
>     return self._get_impl(ident, loading.load_on_pk_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 1094, in _get_impl
>     return db_load_fn(self, primary_key_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/loading.py",
>  line 284, in load_on_pk_identity
>     return q.one()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3325, in one
>     e, dialect, self
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 1547, in _handle_dbapi_exception_noconnection
>     util.raise_from_cause(sqlalchemy_exception, exc_info)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/util/compat.py",
>  line 398, in raise_from_cause
>     ret = self.one_or_none()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3294, in one_or_none
>     ret = list(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3367, in __iter__
>     return self._execute_and_instances(context)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3389, in _execute_and_instances
>     querycontext, self._connection_from_session, close_with_result=True
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3404, in _get_bind_args
>     reraise(type(exception), exception, tb=exc_tb, cause=cause)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2276, in _wrap_pool_connect
>     return fn()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 363, in connect
>     return _ConnectionFairy._checkout(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 760, in _checkout
>     mapper=self._bind_mapper(), clause=querycontext.statement, **kw
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3382, in _connection_from_session
>     fairy = _ConnectionRecord.checkout(pool)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 492, in checkout
>     rec = pool._do_get()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/impl.py",
>  line 238, in _do_get
>     return self._create_connection()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 308, in _create_connection
>     return _ConnectionRecord(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 437, in __init__
>     self.__connect(first_connect_check=True)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 639, in __connect
>     connection = pool._invoke_creator(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/strategies.py",
>  line 114, in connect
>     conn = self.session.connection(**kw)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1133, in connection
>     return dialect.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/default.py",
>  line 482, in connect
>     return self.dbapi.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/__init__.py",
>  line 84, in Connect
>     return Connection(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/connections.py",
>  line 179, in __init__
>     super(Connection, self).__init__(*args, **kwargs2)
>     execution_options=execution_options,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1139, in _connection_for_bind
> sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError) 
> (2005, "Unknown MySQL server host 'redacted_dbhosthere' (11)")
> (Background on this error at: http://sqlalche.me/e/e3q8)
>     engine, execution_options
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 432, in _connection_for_bind
>     conn = bind._contextual_connect()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2242, in _contextual_connect
>     self._wrap_pool_connect(self.pool.connect, None),
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2280, in _wrap_pool_connect
>     return self._get_impl(ident, loading.load_on_pk_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 1094, in _get_impl
>     return db_load_fn(self, primary_key_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/loading.py",
>  line 284, in load_on_pk_identity
>     return q.one()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3325, in one
>     ret = self.one_or_none()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3294, in one_or_none
>     ret = list(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3367, in __iter__
>     return self._execute_and_instances(context)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3389, in _execute_and_instances
>     querycontext, self._connection_from_session, close_with_result=True
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3404, in _get_bind_args
>     mapper=self._bind_mapper(), clause=querycontext.statement, **kw
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3382, in _connection_from_session
>     conn = self.session.connection(**kw)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1133, in connection
>     execution_options=execution_options,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1139, in _connection_for_bind
>     engine, execution_options
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 432, in _connection_for_bind
>     conn = bind._contextual_connect()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2242, in _contextual_connect
>     self._wrap_pool_connect(self.pool.connect, None),
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2280, in _wrap_pool_connect
>     e, dialect, self
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 1547, in _handle_dbapi_exception_noconnection
>     util.raise_from_cause(sqlalchemy_exception, exc_info)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/util/compat.py",
>  line 398, in raise_from_cause
>     reraise(type(exception), exception, tb=exc_tb, cause=cause)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2276, in _wrap_pool_connect
>     return fn()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 363, in connect
>     return _ConnectionFairy._checkout(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 760, in _checkout
>     fairy = _ConnectionRecord.checkout(pool)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 492, in checkout
>     rec = pool._do_get()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/impl.py",
>  line 238, in _do_get
>     return self._create_connection()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 308, in _create_connection
>     return _ConnectionRecord(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 437, in __init__
>     self.__connect(first_connect_check=True)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 639, in __connect
>     connection = pool._invoke_creator(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/strategies.py",
>  line 114, in connect
>     return dialect.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/default.py",
>  line 482, in connect
>     return self.dbapi.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/__init__.py",
>  line 84, in Connect
>     return Connection(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/connections.py",
>  line 179, in __init__
>     super(Connection, self).__init__(*args, **kwargs2)
> sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError) 
> (2005, "Unknown MySQL server host 'redacted_dbhosthere' (11)")
> (Background on this error at: http://sqlalche.me/e/e3q8)
> Traceback (most recent call last):
>   File "/home/ec2-user/venv/bin/airflow", line 37, in <module>
>     args.func(args)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/cli.py", 
> line 74, in wrapper
>     return f(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 551, in run
>     _run(args, dag, ti)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 464, in _run
>     run_job.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/jobs/base_job.py",
>  line 233, in run
>     session.merge(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2113, in merge
>     _resolve_conflict_map=_resolve_conflict_map,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2186, in _merge
>     merged = self.query(mapper.class_).get(key[1])
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 982, in get
>     return self._get_impl(ident, loading.load_on_pk_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 1094, in _get_impl
>     return db_load_fn(self, primary_key_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/loading.py",
>  line 284, in load_on_pk_identity
>     return q.one()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3325, in one
>     ret = self.one_or_none()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3294, in one_or_none
>     ret = list(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3367, in __iter__
>     return self._execute_and_instances(context)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3389, in _execute_and_instances
>     querycontext, self._connection_from_session, close_with_result=True
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3404, in _get_bind_args
>     mapper=self._bind_mapper(), clause=querycontext.statement, **kw
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3382, in _connection_from_session
>     conn = self.session.connection(**kw)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1133, in connection
>     execution_options=execution_options,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1139, in _connection_for_bind
>     engine, execution_options
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 432, in _connection_for_bind
>     conn = bind._contextual_connect()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2242, in _contextual_connect
>     self._wrap_pool_connect(self.pool.connect, None),
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2280, in _wrap_pool_connect
>     e, dialect, self
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 1547, in _handle_dbapi_exception_noconnection
>     e, dialect, self
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 1547, in _handle_dbapi_exception_noconnection
>     util.raise_from_cause(sqlalchemy_exception, exc_info)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/util/compat.py",
>  line 398, in raise_from_cause
>     reraise(type(exception), exception, tb=exc_tb, cause=cause)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2276, in _wrap_pool_connect
>     util.raise_from_cause(sqlalchemy_exception, exc_info)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/util/compat.py",
>  line 398, in raise_from_cause
>     reraise(type(exception), exception, tb=exc_tb, cause=cause)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2276, in _wrap_pool_connect
>     return fn()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 363, in connect
>     return _ConnectionFairy._checkout(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 760, in _checkout
>     return fn()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 363, in connect
>     fairy = _ConnectionRecord.checkout(pool)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 492, in checkout
>     return _ConnectionFairy._checkout(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 760, in _checkout
>     rec = pool._do_get()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/impl.py",
>  line 238, in _do_get
>     return self._create_connection()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 308, in _create_connection
>     fairy = _ConnectionRecord.checkout(pool)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 492, in checkout
>     return _ConnectionRecord(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 437, in __init__
>     rec = pool._do_get()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/impl.py",
>  line 238, in _do_get
>     return self._create_connection()
>       File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 308, in _create_connection
> self.__connect(first_connect_check=True)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 639, in __connect
>     return _ConnectionRecord(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 437, in __init__
>     connection = pool._invoke_creator(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/strategies.py",
>  line 114, in connect
>     self.__connect(first_connect_check=True)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 639, in __connect
>     return dialect.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/default.py",
>  line 482, in connect
>     connection = pool._invoke_creator(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/strategies.py",
>  line 114, in connect
>     return self.dbapi.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/__init__.py",
>  line 84, in Connect
>     return dialect.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/default.py",
>  line 482, in connect
>     return Connection(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/connections.py",
>  line 179, in __init__
>     super(Connection, self).__init__(*args, **kwargs2)
> sqlalchemy.exc    .return self.dbapi.connect(*cargs, **cparams)
> OperationalError  File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/__init__.py",
>  line 84, in Connect
>     return Connection(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/connections.py",
>  line 179, in __init__
> :     super(Connection, self).__init__(*args, **kwargs2)
> (MySQLdb._exceptions.OperationalError) (2005, "Unknown MySQL server host 
> 'redacted_dbhosthere' (11)")
> (Background on this error at: http://sqlalche.me/e/e3q8)
> sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError) 
> (2005, "Unknown MySQL server host 'redacted_dbhosthere' (11)")
> (Background on this error at: http://sqlalche.me/e/e3q8)
> Traceback (most recent call last):
>   File "/home/ec2-user/venv/bin/airflow", line 37, in <module>
>     args.func(args)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/cli.py", 
> line 74, in wrapper
>     return f(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 551, in run
>     _run(args, dag, ti)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 464, in _run
>     run_job.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/jobs/base_job.py",
>  line 233, in run
>     session.merge(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2113, in merge
>     _resolve_conflict_map=_resolve_conflict_map,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2186, in _merge
>     merged = self.query(mapper.class_).get(key[1])
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 982, in get
>     return self._get_impl(ident, loading.load_on_pk_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 1094, in _get_impl
>     return db_load_fn(self, primary_key_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/loading.py",
>  line 284, in load_on_pk_identity
>     return q.one()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3325, in one
>     ret = self.one_or_none()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3294, in one_or_none
>     ret = list(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3367, in __iter__
>     return self._execute_and_instances(context)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3389, in _execute_and_instances
>     querycontext, self._connection_from_session, close_with_result=True
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3404, in _get_bind_args
>     mapper=self._bind_mapper(), clause=querycontext.statement, **kw
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3382, in _connection_from_session
>     conn = self.session.connection(**kw)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1133, in connection
>     execution_options=execution_options,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1139, in _connection_for_bind
>     engine, execution_options
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 432, in _connection_for_bind
>     conn = bind._contextual_connect()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2242, in _contextual_connect
>     self._wrap_pool_connect(self.pool.connect, None),
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2280, in _wrap_pool_connect
>     e, dialect, self
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 1547, in _handle_dbapi_exception_noconnection
>     util.raise_from_cause(sqlalchemy_exception, exc_info)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/util/compat.py",
>  line 398, in raise_from_cause
>     reraise(type(exception), exception, tb=exc_tb, cause=cause)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2276, in _wrap_pool_connect
>     return fn()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 363, in connect
>     return _ConnectionFairy._checkout(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 760, in _checkout
>     fairy = _ConnectionRecord.checkout(pool)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 492, in checkout
>     rec = pool._do_get()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/impl.py",
>  line 238, in _do_get
>     return self._create_connection()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 308, in _create_connection
>     return _ConnectionRecord(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 437, in __init__
>     self.__connect(first_connect_check=True)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 639, in __connect
>     connection = pool._invoke_creator(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/strategies.py",
>  line 114, in connect
>     return dialect.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/default.py",
>  line 482, in connect
>     return self.dbapi.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/__init__.py",
>  line 84, in Connect
>     return Connection(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/connections.py",
>  line 179, in __init__
>     super(Connection, self).__init__(*args, **kwargs2)
> sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError) 
> (2005, "Unknown MySQL server host 'redacted_dbhosthere' (11)")
> (Background on this error at: http://sqlalche.me/e/e3q8)
> Traceback (most recent call last):
>   File "/home/ec2-user/venv/bin/airflow", line 37, in <module>
>     args.func(args)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/cli.py", 
> line 74, in wrapper
>     return f(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 551, in run
>     _run(args, dag, ti)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 464, in _run
>     run_job.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/jobs/base_job.py",
>  line 233, in run
>     session.merge(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2113, in merge
>     _resolve_conflict_map=_resolve_conflict_map,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2186, in _merge
>     merged = self.query(mapper.class_).get(key[1])
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 982, in get
>     return self._get_impl(ident, loading.load_on_pk_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 1094, in _get_impl
>     return db_load_fn(self, primary_key_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/loading.py",
>  line 284, in load_on_pk_identity
>     return q.one()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3325, in one
>     ret = self.one_or_none()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3294, in one_or_none
>     ret = list(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3367, in __iter__
>     return self._execute_and_instances(context)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3389, in _execute_and_instances
>     querycontext, self._connection_from_session, close_with_result=True
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3404, in _get_bind_args
>     mapper=self._bind_mapper(), clause=querycontext.statement, **kw
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3382, in _connection_from_session
>     conn = self.session.connection(**kw)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1133, in connection
>     execution_options=execution_options,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1139, in _connection_for_bind
>     engine, execution_options
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 432, in _connection_for_bind
>     conn = bind._contextual_connect()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2242, in _contextual_connect
>     self._wrap_pool_connect(self.pool.connect, None),
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2280, in _wrap_pool_connect
>     e, dialect, self
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 1547, in _handle_dbapi_exception_noconnection
>     util.raise_from_cause(sqlalchemy_exception, exc_info)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/util/compat.py",
>  line 398, in raise_from_cause
>     reraise(type(exception), exception, tb=exc_tb, cause=cause)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2276, in _wrap_pool_connect
>     return fn()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 363, in connect
>     return _ConnectionFairy._checkout(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 760, in _checkout
>     fairy = _ConnectionRecord.checkout(pool)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 492, in checkout
>     rec = pool._do_get()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/impl.py",
>  line 238, in _do_get
>     return self._create_connection()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 308, in _create_connection
>     return _ConnectionRecord(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 437, in __init__
>     self.__connect(first_connect_check=True)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 639, in __connect
>     connection = pool._invoke_creator(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/strategies.py",
>  line 114, in connect
>     return dialect.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/default.py",
>  line 482, in connect
>     return self.dbapi.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/__init__.py",
>  line 84, in Connect
>     return Connection(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/connections.py",
>  line 179, in __init__
>     super(Connection, self).__init__(*args, **kwargs2)
> sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError) 
> (2005, "Unknown MySQL server host 'redacted_dbhosthere' (11)")
> (Background on this error at: http://sqlalche.me/e/e3q8)
> Traceback (most recent call last):
>   File "/home/ec2-user/venv/bin/airflow", line 37, in <module>
>     args.func(args)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/cli.py", 
> line 74, in wrapper
>     return f(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 551, in run
>     _run(args, dag, ti)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 464, in _run
>     run_job.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/jobs/base_job.py",
>  line 233, in run
>     session.merge(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2113, in merge
>     _resolve_conflict_map=_resolve_conflict_map,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2186, in _merge
>     merged = self.query(mapper.class_).get(key[1])
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 982, in get
>     return self._get_impl(ident, loading.load_on_pk_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 1094, in _get_impl
>     return db_load_fn(self, primary_key_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/loading.py",
>  line 284, in load_on_pk_identity
>     return q.one()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3325, in one
>     ret = self.one_or_none()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3294, in one_or_none
>     ret = list(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3367, in __iter__
>     return self._execute_and_instances(context)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3389, in _execute_and_instances
>     querycontext, self._connection_from_session, close_with_result=True
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3404, in _get_bind_args
>     mapper=self._bind_mapper(), clause=querycontext.statement, **kw
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3382, in _connection_from_session
>     conn = self.session.connection(**kw)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1133, in connection
>     execution_options=execution_options,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1139, in _connection_for_bind
>     engine, execution_options
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 432, in _connection_for_bind
>     conn = bind._contextual_connect()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2242, in _contextual_connect
>     self._wrap_pool_connect(self.pool.connect, None),
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2280, in _wrap_pool_connect
>     e, dialect, self
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 1547, in _handle_dbapi_exception_noconnection
>     util.raise_from_cause(sqlalchemy_exception, exc_info)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/util/compat.py",
>  line 398, in raise_from_cause
>     reraise(type(exception), exception, tb=exc_tb, cause=cause)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2276, in _wrap_pool_connect
>     return fn()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 363, in connect
>     return _ConnectionFairy._checkout(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 760, in _checkout
>     fairy = _ConnectionRecord.checkout(pool)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 492, in checkout
>     rec = pool._do_get()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/impl.py",
>  line 238, in _do_get
>     return self._create_connection()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 308, in _create_connection
>     return _ConnectionRecord(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 437, in __init__
>     self.__connect(first_connect_check=True)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 639, in __connect
>     connection = pool._invoke_creator(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/strategies.py",
>  line 114, in connect
>     return dialect.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/default.py",
>  line 482, in connect
>     return self.dbapi.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/__init__.py",
>  line 84, in Connect
>     return Connection(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/connections.py",
>  line 179, in __init__
>     super(Connection, self).__init__(*args, **kwargs2)
> sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError) 
> (2005, "Unknown MySQL server host 'redacted_dbhosthere' (11)")
> (Background on this error at: http://sqlalche.me/e/e3q8)
> Traceback (most recent call last):
>   File "/home/ec2-user/venv/bin/airflow", line 37, in <module>
>     args.func(args)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/cli.py", 
> line 74, in wrapper
>     return f(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 551, in run
>     _run(args, dag, ti)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 464, in _run
>     run_job.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/jobs/base_job.py",
>  line 233, in run
>     session.merge(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2113, in merge
>     _resolve_conflict_map=_resolve_conflict_map,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2186, in _merge
>     merged = self.query(mapper.class_).get(key[1])
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 982, in get
>     return self._get_impl(ident, loading.load_on_pk_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 1094, in _get_impl
>     return db_load_fn(self, primary_key_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/loading.py",
>  line 284, in load_on_pk_identity
>     return q.one()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3325, in one
>     ret = self.one_or_none()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3294, in one_or_none
>     ret = list(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3367, in __iter__
>     return self._execute_and_instances(context)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3389, in _execute_and_instances
>     querycontext, self._connection_from_session, close_with_result=True
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3404, in _get_bind_args
>     mapper=self._bind_mapper(), clause=querycontext.statement, **kw
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3382, in _connection_from_session
>     conn = self.session.connection(**kw)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1133, in connection
>     execution_options=execution_options,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1139, in _connection_for_bind
>     engine, execution_options
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 432, in _connection_for_bind
>     conn = bind._contextual_connect()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2242, in _contextual_connect
>     self._wrap_pool_connect(self.pool.connect, None),
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2280, in _wrap_pool_connect
>     e, dialect, self
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 1547, in _handle_dbapi_exception_noconnection
>     util.raise_from_cause(sqlalchemy_exception, exc_info)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/util/compat.py",
>  line 398, in raise_from_cause
>     reraise(type(exception), exception, tb=exc_tb, cause=cause)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2276, in _wrap_pool_connect
>     return fn()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 363, in connect
>     return _ConnectionFairy._checkout(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 760, in _checkout
>     fairy = _ConnectionRecord.checkout(pool)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 492, in checkout
>     rec = pool._do_get()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/impl.py",
>  line 238, in _do_get
>     return self._create_connection()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 308, in _create_connection
>     return _ConnectionRecord(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 437, in __init__
>     self.__connect(first_connect_check=True)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 639, in __connect
>     connection = pool._invoke_creator(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/strategies.py",
>  line 114, in connect
>     return dialect.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/default.py",
>  line 482, in connect
>     return self.dbapi.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/__init__.py",
>  line 84, in Connect
>     return Connection(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/connections.py",
>  line 179, in __init__
>     super(Connection, self).__init__(*args, **kwargs2)
> sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError) 
> (2005, "Unknown MySQL server host 'redacted_dbhosthere' (11)")
> (Background on this error at: http://sqlalche.me/e/e3q8)
> Traceback (most recent call last):
>   File "/home/ec2-user/venv/bin/airflow", line 37, in <module>
>     args.func(args)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/cli.py", 
> line 74, in wrapper
>     return f(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 551, in run
>     _run(args, dag, ti)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 464, in _run
>     run_job.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/jobs/base_job.py",
>  line 233, in run
>     session.merge(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2113, in merge
>     _resolve_conflict_map=_resolve_conflict_map,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2186, in _merge
>     merged = self.query(mapper.class_).get(key[1])
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 982, in get
>     return self._get_impl(ident, loading.load_on_pk_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 1094, in _get_impl
>     return db_load_fn(self, primary_key_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/loading.py",
>  line 284, in load_on_pk_identity
>     return q.one()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3325, in one
>     ret = self.one_or_none()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3294, in one_or_none
>     ret = list(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3367, in __iter__
>     return self._execute_and_instances(context)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3389, in _execute_and_instances
>     querycontext, self._connection_from_session, close_with_result=True
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3404, in _get_bind_args
>     mapper=self._bind_mapper(), clause=querycontext.statement, **kw
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3382, in _connection_from_session
>     conn = self.session.connection(**kw)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1133, in connection
>     execution_options=execution_options,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1139, in _connection_for_bind
>     engine, execution_options
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 432, in _connection_for_bind
>     conn = bind._contextual_connect()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2242, in _contextual_connect
>     self._wrap_pool_connect(self.pool.connect, None),
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2280, in _wrap_pool_connect
>     e, dialect, self
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 1547, in _handle_dbapi_exception_noconnection
>     util.raise_from_cause(sqlalchemy_exception, exc_info)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/util/compat.py",
>  line 398, in raise_from_cause
>     reraise(type(exception), exception, tb=exc_tb, cause=cause)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2276, in _wrap_pool_connect
>     return fn()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 363, in connect
>     return _ConnectionFairy._checkout(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 760, in _checkout
>     fairy = _ConnectionRecord.checkout(pool)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 492, in checkout
>     rec = pool._do_get()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/impl.py",
>  line 238, in _do_get
>     return self._create_connection()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 308, in _create_connection
>     return _ConnectionRecord(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 437, in __init__
>     self.__connect(first_connect_check=True)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 639, in __connect
>     connection = pool._invoke_creator(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/strategies.py",
>  line 114, in connect
>     return dialect.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/default.py",
>  line 482, in connect
>     return self.dbapi.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/__init__.py",
>  line 84, in Connect
>     return Connection(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/connections.py",
>  line 179, in __init__
>     super(Connection, self).__init__(*args, **kwargs2)
> sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError) 
> (2005, "Unknown MySQL server host 'redacted_dbhosthere' (11)")
> (Background on this error at: http://sqlalche.me/e/e3q8)
> Traceback (most recent call last):
>   File "/home/ec2-user/venv/bin/airflow", line 37, in <module>
>     args.func(args)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/cli.py", 
> line 74, in wrapper
>     return f(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 551, in run
>     _run(args, dag, ti)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 464, in _run
>     run_job.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/jobs/base_job.py",
>  line 233, in run
>     session.merge(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2113, in merge
>     _resolve_conflict_map=_resolve_conflict_map,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2186, in _merge
>     merged = self.query(mapper.class_).get(key[1])
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 982, in get
>     return self._get_impl(ident, loading.load_on_pk_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 1094, in _get_impl
>     return db_load_fn(self, primary_key_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/loading.py",
>  line 284, in load_on_pk_identity
>     return q.one()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3325, in one
>     ret = self.one_or_none()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3294, in one_or_none
>     ret = list(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3367, in __iter__
>     return self._execute_and_instances(context)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3389, in _execute_and_instances
>     querycontext, self._connection_from_session, close_with_result=True
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3404, in _get_bind_args
>     mapper=self._bind_mapper(), clause=querycontext.statement, **kw
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3382, in _connection_from_session
>     conn = self.session.connection(**kw)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1133, in connection
>     execution_options=execution_options,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1139, in _connection_for_bind
>     engine, execution_options
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 432, in _connection_for_bind
>     conn = bind._contextual_connect()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2242, in _contextual_connect
>     self._wrap_pool_connect(self.pool.connect, None),
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2280, in _wrap_pool_connect
>     e, dialect, self
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 1547, in _handle_dbapi_exception_noconnection
>     util.raise_from_cause(sqlalchemy_exception, exc_info)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/util/compat.py",
>  line 398, in raise_from_cause
>     reraise(type(exception), exception, tb=exc_tb, cause=cause)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2276, in _wrap_pool_connect
>     return fn()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 363, in connect
>     return _ConnectionFairy._checkout(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 760, in _checkout
>     fairy = _ConnectionRecord.checkout(pool)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 492, in checkout
>     rec = pool._do_get()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/impl.py",
>  line 238, in _do_get
>     return self._create_connection()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 308, in _create_connection
>     return _ConnectionRecord(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 437, in __init__
>     self.__connect(first_connect_check=True)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 639, in __connect
>     connection = pool._invoke_creator(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/strategies.py",
>  line 114, in connect
>     return dialect.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/default.py",
>  line 482, in connect
>     return self.dbapi.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/__init__.py",
>  line 84, in Connect
>     return Connection(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/connections.py",
>  line 179, in __init__
>     super(Connection, self).__init__(*args, **kwargs2)
> sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError) 
> (2005, "Unknown MySQL server host 'redacted_dbhosthere' (11)")
> (Background on this error at: http://sqlalche.me/e/e3q8)
> Traceback (most recent call last):
>   File "/home/ec2-user/venv/bin/airflow", line 37, in <module>
>     args.func(args)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/cli.py", 
> line 74, in wrapper
>     return f(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 551, in run
>     _run(args, dag, ti)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 464, in _run
>     run_job.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/jobs/base_job.py",
>  line 233, in run
>     session.merge(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2113, in merge
>     _resolve_conflict_map=_resolve_conflict_map,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2186, in _merge
>     merged = self.query(mapper.class_).get(key[1])
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 982, in get
>     return self._get_impl(ident, loading.load_on_pk_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 1094, in _get_impl
>     return db_load_fn(self, primary_key_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/loading.py",
>  line 284, in load_on_pk_identity
>     return q.one()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3325, in one
>     ret = self.one_or_none()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3294, in one_or_none
>     ret = list(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3367, in __iter__
>     return self._execute_and_instances(context)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3389, in _execute_and_instances
>     querycontext, self._connection_from_session, close_with_result=True
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3404, in _get_bind_args
>     mapper=self._bind_mapper(), clause=querycontext.statement, **kw
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3382, in _connection_from_session
>     conn = self.session.connection(**kw)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1133, in connection
>     execution_options=execution_options,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1139, in _connection_for_bind
>     engine, execution_options
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 432, in _connection_for_bind
>     conn = bind._contextual_connect()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2242, in _contextual_connect
>     self._wrap_pool_connect(self.pool.connect, None),
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2280, in _wrap_pool_connect
>     e, dialect, self
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 1547, in _handle_dbapi_exception_noconnection
>     util.raise_from_cause(sqlalchemy_exception, exc_info)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/util/compat.py",
>  line 398, in raise_from_cause
>     reraise(type(exception), exception, tb=exc_tb, cause=cause)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2276, in _wrap_pool_connect
>     return fn()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 363, in connect
>     return _ConnectionFairy._checkout(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 760, in _checkout
>     fairy = _ConnectionRecord.checkout(pool)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 492, in checkout
>     rec = pool._do_get()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/impl.py",
>  line 238, in _do_get
>     return self._create_connection()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 308, in _create_connection
>     return _ConnectionRecord(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 437, in __init__
>     self.__connect(first_connect_check=True)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 639, in __connect
>     connection = pool._invoke_creator(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/strategies.py",
>  line 114, in connect
>     return dialect.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/default.py",
>  line 482, in connect
>     return self.dbapi.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/__init__.py",
>  line 84, in Connect
>     return Connection(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/connections.py",
>  line 179, in __init__
>     super(Connection, self).__init__(*args, **kwargs2)
> sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError) 
> (2005, "Unknown MySQL server host 'redacted_dbhosthere' (11)")
> (Background on this error at: http://sqlalche.me/e/e3q8)
> Traceback (most recent call last):
>   File "/home/ec2-user/venv/bin/airflow", line 37, in <module>
>     args.func(args)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/cli.py", 
> line 74, in wrapper
>     return f(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 551, in run
>     _run(args, dag, ti)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 464, in _run
> Traceback (most recent call last):
>   File "/home/ec2-user/venv/bin/airflow", line 37, in <module>
>     args.func(args)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/cli.py", 
> line 74, in wrapper
>         run_job.run()
> return f(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/jobs/base_job.py",
>  line 233, in run
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 551, in run
>     session.merge(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2113, in merge
>     _run(args, dag, ti)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 464, in _run
>     run_job.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/jobs/base_job.py",
>  line 233, in run
>     session.merge(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2113, in merge
>     _resolve_conflict_map=_resolve_conflict_map,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2186, in _merge
>     _resolve_conflict_map=_resolve_conflict_map,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2186, in _merge
>     merged = self.query(mapper.class_).get(key[1])
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 982, in get
>     return self._get_impl(ident, loading.load_on_pk_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 1094, in _get_impl
>     merged = self.query(mapper.class_).get(key[1])
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 982, in get
>     return self._get_impl(ident, loading.load_on_pk_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 1094, in _get_impl
>     return db_load_fn(self, primary_key_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/loading.py",
>  line 284, in load_on_pk_identity
>     return q.one()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3325, in one
>     ret = self.one_or_none()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3294, in one_or_none
>     ret = list(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3367, in __iter__
> Traceback (most recent call last):
>   File "/home/ec2-user/venv/bin/airflow", line 37, in <module>
>     args.func(args)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/cli.py", 
> line 74, in wrapper
>     return f(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 551, in run
>     _run(args, dag, ti)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 464, in _run
> Traceback (most recent call last):
>   File "/home/ec2-user/venv/bin/airflow", line 37, in <module>
>     args.func(args)
>       File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/cli.py", 
> line 74, in wrapper
> run_job.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/jobs/base_job.py",
>  line 233, in run
>     return f(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 551, in run
>     session.merge(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2113, in merge
>     _run(args, dag, ti)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 464, in _run
>     run_job.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/jobs/base_job.py",
>  line 233, in run
>     session.merge(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2113, in merge
>     return self._execute_and_instances(context)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3389, in _execute_and_instances
>     _resolve_conflict_map=_resolve_conflict_map,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2186, in _merge
>     _resolve_conflict_map=_resolve_conflict_map,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2186, in _merge
>     merged = self.query(mapper.class_).get(key[1])
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 982, in get
>     querycontext, self._connection_from_session, close_with_result=True
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3404, in _get_bind_args
>     merged = self.query(mapper.class_).get(key[1])
>     return self._get_impl(ident, loading.load_on_pk_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 982, in get
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 1094, in _get_impl
>     return self._get_impl(ident, loading.load_on_pk_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 1094, in _get_impl
>     return db_load_fn(self, primary_key_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/loading.py",
>  line 284, in load_on_pk_identity
>     return q.one()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3325, in one
>     return db_load_fn(self, primary_key_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/loading.py",
>  line 284, in load_on_pk_identity
>     return q.one()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3325, in one
>     mapper=self._bind_mapper(), clause=querycontext.statement, **kw
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3382, in _connection_from_session
>     ret = self.one_or_none()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3294, in one_or_none
>     ret = self.one_or_none()
> Traceback (most recent call last):
>   File "/home/ec2-user/venv/bin/airflow", line 37, in <module>
>     args.func(args)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/cli.py", 
> line 74, in wrapper
>     return f(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 551, in run
>     _run(args, dag, ti)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 464, in _run
>     conn = self.session.connection(**kw)
>       File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1133, in connection
> run_job.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/jobs/base_job.py",
>  line 233, in run
>     session.merge(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2113, in merge
>     execution_options=execution_options,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1139, in _connection_for_bind
>     engine, execution_options
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 432, in _connection_for_bind
>     _resolve_conflict_map=_resolve_conflict_map,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2186, in _merge
>     conn = bind._contextual_connect()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2242, in _contextual_connect
>     self._wrap_pool_connect(self.pool.connect, None),
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2280, in _wrap_pool_connect
>     merged = self.query(mapper.class_).get(key[1])
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 982, in get
>     e, dialect, self
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 1547, in _handle_dbapi_exception_noconnection
>     util.raise_from_cause(sqlalchemy_exception, exc_info)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/util/compat.py",
>  line 398, in raise_from_cause
>     reraise(type(exception), exception, tb=exc_tb, cause=cause)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2276, in _wrap_pool_connect
>     return fn()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 363, in connect
>     return _ConnectionFairy._checkout(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 760, in _checkout
>     fairy = _ConnectionRecord.checkout(pool)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 492, in checkout
>     rec = pool._do_get()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/impl.py",
>  line 238, in _do_get
>     return self._create_connection()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 308, in _create_connection
>     return _ConnectionRecord(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 437, in __init__
>     self.__connect(first_connect_check=True)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 639, in __connect
>     connection = pool._invoke_creator(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/strategies.py",
>  line 114, in connect
>     return dialect.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/default.py",
>  line 482, in connect
>     return self.dbapi.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/__init__.py",
>  line 84, in Connect
>     return Connection(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/connections.py",
>  line 179, in __init__
>     super(Connection, self).__init__(*args, **kwargs2)
> sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError) 
> (2005, "Unknown MySQL server host 'redacted_dbhosthere' (11)")
> (Background on this error at: http://sqlalche.me/e/e3q8)
>     return db_load_fn(self, primary_key_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/loading.py",
>  line 284, in load_on_pk_identity
>     return q.one()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3325, in one
>     ret = self.one_or_none()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3294, in one_or_none
>     ret = list(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3367, in __iter__
>     return self._execute_and_instances(context)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3389, in _execute_and_instances
>     querycontext, self._connection_from_session, close_with_result=True
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3404, in _get_bind_args
>     mapper=self._bind_mapper(), clause=querycontext.statement, **kw
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3382, in _connection_from_session
>     conn = self.session.connection(**kw)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1133, in connection
>     execution_options=execution_options,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1139, in _connection_for_bind
>     engine, execution_options
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 432, in _connection_for_bind
>     conn = bind._contextual_connect()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2242, in _contextual_connect
>     self._wrap_pool_connect(self.pool.connect, None),
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2280, in _wrap_pool_connect
>     e, dialect, self
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 1547, in _handle_dbapi_exception_noconnection
>     util.raise_from_cause(sqlalchemy_exception, exc_info)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/util/compat.py",
>  line 398, in raise_from_cause
>     reraise(type(exception), exception, tb=exc_tb, cause=cause)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2276, in _wrap_pool_connect
>     return fn()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 363, in connect
>     return _ConnectionFairy._checkout(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 760, in _checkout
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3294, in one_or_none
>     ret = list(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3367, in __iter__
>     return self._execute_and_instances(context)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3389, in _execute_and_instances
>     querycontext, self._connection_from_session, close_with_result=True
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3404, in _get_bind_args
>     mapper=self._bind_mapper(), clause=querycontext.statement, **kw
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3382, in _connection_from_session
> Process QueuedLocalWorker-17:
> Traceback (most recent call last):
> Process QueuedLocalWorker-2:
> Process QueuedLocalWorker-10:
>   File "/usr/lib64/python2.7/multiprocessing/process.py", line 267, in 
> _bootstrap
> Traceback (most recent call last):
> Traceback (most recent call last):
>       File "/usr/lib64/python2.7/multiprocessing/process.py", line 267, in 
> _bootstrap
> conn = self.session.connection(**kw)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1133, in connection
>   File "/usr/lib64/python2.7/multiprocessing/process.py", line 267, in 
> _bootstrap
>     execution_options=execution_options,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1139, in _connection_for_bind
>     engine, execution_options
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 432, in _connection_for_bind
>     conn = bind._contextual_connect()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2242, in _contextual_connect
> Process QueuedLocalWorker-4:
> Traceback (most recent call last):
> Process QueuedLocalWorker-7:
>   File "/usr/lib64/python2.7/multiprocessing/process.py", line 267, in 
> _bootstrap
> Traceback (most recent call last):
>     self.run()
>   File "/usr/lib64/python2.7/multiprocessing/process.py", line 267, in 
> _bootstrap
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/executors/local_executor.py",
>  line 118, in run
>     self.task_queue.task_done()
>   File "<string>", line 2, in task_done
>     self.run()
>   File "/usr/lib64/python2.7/multiprocessing/managers.py", line 759, in 
> _callmethod
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/executors/local_executor.py",
>  line 118, in run
>     self._wrap_pool_connect(self.pool.connect, None),
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2280, in _wrap_pool_connect
>     self.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/executors/local_executor.py",
>  line 118, in run
>     self.task_queue.task_done()
>   File "<string>", line 2, in task_done
>   File "/usr/lib64/python2.7/multiprocessing/managers.py", line 759, in 
> _callmethod
>     self.task_queue.task_done()
>   File "<string>", line 2, in task_done
>     self.run()
>   File "/usr/lib64/python2.7/multiprocessing/managers.py", line 759, in 
> _callmethod
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/executors/local_executor.py",
>  line 118, in run
>     self.task_queue.task_done()
>   File "<string>", line 2, in task_done
>     e, dialect, self
>   File "/usr/lib64/python2.7/multiprocessing/managers.py", line 759, in 
> _callmethod
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 1547, in _handle_dbapi_exception_noconnection
>     self.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/executors/local_executor.py",
>  line 118, in run
>     util.raise_from_cause(sqlalchemy_exception, exc_info)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/util/compat.py",
>  line 398, in raise_from_cause
>     reraise(type(exception), exception, tb=exc_tb, cause=cause)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2276, in _wrap_pool_connect
>     self.task_queue.task_done()
>   File "<string>", line 2, in task_done
>   File "/usr/lib64/python2.7/multiprocessing/managers.py", line 759, in 
> _callmethod
>     return fn()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 363, in connect
>     return _ConnectionFairy._checkout(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 760, in _checkout
>     kind, result = conn.recv()
>     kind, result = conn.recv()
> IOError: [Errno 104] Connection reset by peer
> IOError: [Errno 104] Connection reset by peer
>     fairy = _ConnectionRecord.checkout(pool)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 492, in checkout
>     rec = pool._do_get()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/impl.py",
>  line 238, in _do_get
>     return self._create_connection()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 308, in _create_connection
>     return _ConnectionRecord(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 437, in __init__
>     self.__connect(first_connect_check=True)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 639, in __connect
>     connection = pool._invoke_creator(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/strategies.py",
>  line 114, in connect
>     return dialect.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/default.py",
>  line 482, in connect
>     return self.dbapi.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/__init__.py",
>  line 84, in Connect
>     return Connection(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/connections.py",
>  line 179, in __init__
>     super(Connection, self).__init__(*args, **kwargs2)
> sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError) 
> (2005, "Unknown MySQL server host 'redacted_dbhosthere' (11)")
> (Background on this error at: http://sqlalche.me/e/e3q8)
> Process QueuedLocalWorker-14:
> Traceback (most recent call last):
>   File "/usr/lib64/python2.7/multiprocessing/process.py", line 267, in 
> _bootstrap
>     self.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/executors/local_executor.py",
>  line 118, in run
>     self.task_queue.task_done()
>   File "<string>", line 2, in task_done
>   File "/usr/lib64/python2.7/multiprocessing/managers.py", line 759, in 
> _callmethod
>     kind, result = conn.recv()
> IOError: [Errno 104] Connection reset by peer
>     kind, result = conn.recv()
> IOError: [Errno 104] Connection reset by peer
>     kind, result = conn.recv()
> IOError: [Errno 104] Connection reset by peer
>     kind, result = conn.recv()
> IOError: [Errno 104] Connection reset by peer
>     return self._get_impl(ident, loading.load_on_pk_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 1094, in _get_impl
>     return db_load_fn(self, primary_key_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/loading.py",
>  line 284, in load_on_pk_identity
>     return q.one()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3325, in one
> Traceback (most recent call last):
>   File "/home/ec2-user/venv/bin/airflow", line 37, in <module>
>     args.func(args)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/utils/cli.py", 
> line 74, in wrapper
>     return f(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 551, in run
>     _run(args, dag, ti)
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/bin/cli.py", 
> line 464, in _run
>     run_job.run()
>   File 
> "/home/ec2-user/venv/local/lib/python2.7/site-packages/airflow/jobs/base_job.py",
>  line 233, in run
>     ret = self.one_or_none()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3294, in one_or_none
>     session.merge(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2113, in merge
>     _resolve_conflict_map=_resolve_conflict_map,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 2186, in _merge
>     ret = list(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3367, in __iter__
>     merged = self.query(mapper.class_).get(key[1])
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 982, in get
>     return self._execute_and_instances(context)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3389, in _execute_and_instances
>     return self._get_impl(ident, loading.load_on_pk_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 1094, in _get_impl
>     return db_load_fn(self, primary_key_identity)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/loading.py",
>  line 284, in load_on_pk_identity
>     return q.one()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3325, in one
>     querycontext, self._connection_from_session, close_with_result=True
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3404, in _get_bind_args
>     fairy = _ConnectionRecord.checkout(pool)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 492, in checkout
>     rec = pool._do_get()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/impl.py",
>  line 238, in _do_get
>         return self._create_connection()
> mapper=self._bind_mapper(), clause=querycontext.statement, **kw
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 308, in _create_connection
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3382, in _connection_from_session
>     return _ConnectionRecord(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 437, in __init__
>     self.__connect(first_connect_check=True)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 639, in __connect
>     connection = pool._invoke_creator(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/strategies.py",
>  line 114, in connect
>     return dialect.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/default.py",
>  line 482, in connect
>     return self.dbapi.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/__init__.py",
>  line 84, in Connect
>     return Connection(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/connections.py",
>  line 179, in __init__
>     super(Connection, self).__init__(*args, **kwargs2)
> sqlalchemy.exc.OperationalError    conn = self.session.connection(**kw)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1133, in connection
> : (MySQLdb._exceptions.OperationalError) (2005, "Unknown MySQL server host 
> 'redacted_dbhosthere' (11)")
> (Background on this error at: http://sqlalche.me/e/e3q8)
>     execution_options=execution_options,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1139, in _connection_for_bind
>     engine, execution_options
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 432, in _connection_for_bind
>     conn = bind._contextual_connect()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2242, in _contextual_connect
>     self._wrap_pool_connect(self.pool.connect, None),
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2280, in _wrap_pool_connect
>     e, dialect, self
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 1547, in _handle_dbapi_exception_noconnection
>     util.raise_from_cause(sqlalchemy_exception, exc_info)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/util/compat.py",
>  line 398, in raise_from_cause
>     reraise(type(exception), exception, tb=exc_tb, cause=cause)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2276, in _wrap_pool_connect
>     return fn()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 363, in connect
>     return _ConnectionFairy._checkout(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 760, in _checkout
>     fairy = _ConnectionRecord.checkout(pool)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 492, in checkout
>     rec = pool._do_get()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/impl.py",
>  line 238, in _do_get
>     return self._create_connection()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 308, in _create_connection
>     return _ConnectionRecord(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 437, in __init__
>     self.__connect(first_connect_check=True)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 639, in __connect
>     connection = pool._invoke_creator(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/strategies.py",
>  line 114, in connect
>     return dialect.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/default.py",
>  line 482, in connect
>     return self.dbapi.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/__init__.py",
>  line 84, in Connect
>     return Connection(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/connections.py",
>  line 179, in __init__
>     super(Connection, self).__init__(*args, **kwargs2)
> sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError) 
> (2005, "Unknown MySQL server host 'redacted_dbhosthere' (11)")
> (Background on this error at: http://sqlalche.me/e/e3q8)
>     ret = list(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3367, in __iter__
>     return self._execute_and_instances(context)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3389, in _execute_and_instances
>     querycontext, self._connection_from_session, close_with_result=True
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3404, in _get_bind_args
>     mapper=self._bind_mapper(), clause=querycontext.statement, **kw
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3382, in _connection_from_session
>     conn = self.session.connection(**kw)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1133, in connection
>     execution_options=execution_options,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1139, in _connection_for_bind
>     engine, execution_options
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 432, in _connection_for_bind
>     conn = bind._contextual_connect()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2242, in _contextual_connect
>     self._wrap_pool_connect(self.pool.connect, None),
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2280, in _wrap_pool_connect
>     e, dialect, self
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 1547, in _handle_dbapi_exception_noconnection
>     util.raise_from_cause(sqlalchemy_exception, exc_info)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/util/compat.py",
>  line 398, in raise_from_cause
>     ret = self.one_or_none()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3294, in one_or_none
>     reraise(type(exception), exception, tb=exc_tb, cause=cause)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2276, in _wrap_pool_connect
>     return fn()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 363, in connect
>     return _ConnectionFairy._checkout(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 760, in _checkout
>     fairy = _ConnectionRecord.checkout(pool)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 492, in checkout
>     ret = list(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3367, in __iter__
>     rec = pool._do_get()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/impl.py",
>  line 238, in _do_get
>     return self._create_connection()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 308, in _create_connection
>     return _ConnectionRecord(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 437, in __init__
>     self.__connect(first_connect_check=True)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 639, in __connect
>     connection = pool._invoke_creator(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/strategies.py",
>  line 114, in connect
>     return dialect.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/default.py",
>  line 482, in connect
>     return self.dbapi.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/__init__.py",
>  line 84, in Connect
>     return Connection(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/connections.py",
>  line 179, in __init__
>     super(Connection, self).__init__(*args, **kwargs2)
> sqlalchemy.exc.OperationalError    return self._execute_and_instances(context)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3389, in _execute_and_instances
> : (MySQLdb._exceptions.OperationalError) (2005, "Unknown MySQL server host 
> 'redacted_dbhosthere' (11)")
> (Background on this error at: http://sqlalche.me/e/e3q8)
>     querycontext, self._connection_from_session, close_with_result=True
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3404, in _get_bind_args
>     mapper=self._bind_mapper(), clause=querycontext.statement, **kw
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/query.py",
>  line 3382, in _connection_from_session
>     conn = self.session.connection(**kw)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1133, in connection
>     execution_options=execution_options,
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 1139, in _connection_for_bind
>     engine, execution_options
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/orm/session.py",
>  line 432, in _connection_for_bind
>     conn = bind._contextual_connect()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2242, in _contextual_connect
>     self._wrap_pool_connect(self.pool.connect, None),
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2280, in _wrap_pool_connect
>     e, dialect, self
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 1547, in _handle_dbapi_exception_noconnection
>     util.raise_from_cause(sqlalchemy_exception, exc_info)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/util/compat.py",
>  line 398, in raise_from_cause
>     reraise(type(exception), exception, tb=exc_tb, cause=cause)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/base.py",
>  line 2276, in _wrap_pool_connect
>     return fn()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 363, in connect
>     return _ConnectionFairy._checkout(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 760, in _checkout
>     fairy = _ConnectionRecord.checkout(pool)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 492, in checkout
>     rec = pool._do_get()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/impl.py",
>  line 238, in _do_get
>     return self._create_connection()
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 308, in _create_connection
>     return _ConnectionRecord(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 437, in __init__
>     self.__connect(first_connect_check=True)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/pool/base.py",
>  line 639, in __connect
>     connection = pool._invoke_creator(self)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/strategies.py",
>  line 114, in connect
>     return dialect.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/sqlalchemy/engine/default.py",
>  line 482, in connect
>     return self.dbapi.connect(*cargs, **cparams)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/__init__.py",
>  line 84, in Connect
>     return Connection(*args, **kwargs)
>   File 
> "/home/ec2-user/venv/local/lib64/python2.7/site-packages/MySQLdb/connections.py",
>  line 179, in __init__
>     super(Connection, self).__init__(*args, **kwargs2)
> sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError) 
> (2005, "Unknown MySQL server host 'redacted_dbhosthere' (11)")
> (Background on this error at: http://sqlalche.me/e/e3q8)
> [2020-01-08 17:35:54,711] {scheduler_job.py:989} INFO - DAG mydag has 5/21 
> running and queued tasks



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