[openstack-dev] [TaskFlow] TaskFlow persistence: Job failure retry

pnkk pnkk2016 at gmail.com
Sun Jun 5 18:14:57 UTC 2016


I am working on NFV orchestrator based on MANO

Regards,
Kanthi

On Thu, Jun 2, 2016 at 3:00 AM, Joshua Harlow <harlowja at fastmail.com> wrote:

> Interesting way to combine taskflow + celery.
>
> I didn't expect it to be used like this, but the more power to you!
>
> Taskflow itself has some similar capabilities via
> http://docs.openstack.org/developer/taskflow/workers.html#design but
> anyway what u've done is pretty neat as well.
>
> I am assuming this isn't an openstack project (due to usage of celery),
> any details on what's being worked on (am curious here)?
>
> pnkk wrote:
>
>> Thanks for the nice documentation.
>>
>> To my knowledge celery is widely used for distributed task processing.
>> This fits our requirement perfectly where we want to return immediate
>> response to the user from our API server and run long running task in
>> background. Celery also gives flexibility with the worker
>> types(process(can overcome GIL problems too)/evetlet...) and it also
>> provides nice message brokers(rabbitmq,redis...)
>>
>> We used both celery and taskflow for our core processing to leverage the
>> benefits of both. Taskflow provides nice primitives like(execute,
>> revert, pre,post stuf) which takes off the load from the application.
>>
>> As far as the actual issue is concerned, I found one way to solve it by
>> using celery "retry" option. This along with late_acks makes the
>> application highly fault tolerant.
>>
>> http://docs.celeryproject.org/en/latest/faq.html#faq-acks-late-vs-retry
>>
>> Regards,
>> Kanthi
>>
>>
>> On Sat, May 28, 2016 at 1:51 AM, Joshua Harlow <harlowja at fastmail.com
>> <mailto:harlowja at fastmail.com>> wrote:
>>
>>     Seems like u could just use
>>     http://docs.openstack.org/developer/taskflow/jobs.html (it appears
>>     that you may not be?); the job itself would when failed be then
>>     worked on by a different job consumer.
>>
>>     Have u looked at those? It almost appears that u are using celery as
>>     a job distribution system (similar to the jobs.html link mentioned
>>     above)? Is that somewhat correct (I haven't seen anyone try this,
>>     wondering how u are using it and the choices that directed u to
>>     that, aka, am curious)?
>>
>>     -Josh
>>
>>     pnkk wrote:
>>
>>         To be specific, we hit this issue when the node running our
>>         service is
>>         rebooted.
>>         Our solution is designed in a way that each and every job is a
>>         celery
>>         task and inside celery task, we create taskflow flow.
>>
>>         We enabled late_acks in celery(uses rabbitmq as message broker),
>>         so if
>>         our service/node goes down, other healthy service can pick the
>>         job and
>>         completes it.
>>         This works fine, but we just hit this rare case where the node was
>>         rebooted just when taskflow is updating something to the database.
>>
>>         In this case, it raises an exception and the job is marked
>>         failed. Since
>>         it is complete(with failure), message is removed from the
>>         rabbitmq and
>>         other worker would not be able to process it.
>>         Can taskflow handle such I/O errors gracefully or should
>>         application try
>>         to catch this exception? If application has to handle it what
>> would
>>         happen to that particular database transaction which failed just
>>         when
>>         the node is rebooted? Who will retry this transaction?
>>
>>         Thanks,
>>         Kanthi
>>
>>         On Fri, May 27, 2016 at 5:39 PM, pnkk <pnkk2016 at gmail.com
>>         <mailto:pnkk2016 at gmail.com>
>>         <mailto:pnkk2016 at gmail.com <mailto:pnkk2016 at gmail.com>>> wrote:
>>
>>              Hi,
>>
>>              When taskflow engine is executing a job, the execution
>>         failed due to
>>              IO error(traceback pasted below).
>>
>>              2016-05-25 19:45:21.717 7119 ERROR
>>              taskflow.engines.action_engine.engine 127.0.1.1 [-]  Engine
>>              execution has failed, something bad must of happened (last 10
>>              machine transitions were [('SCHEDULING', 'WAITING'),
>>         ('WAITING',
>>         'ANALYZING'), ('ANALYZING', 'SCHEDULING'), ('SCHEDULING',
>>         'WAITING'), ('WAITING', 'ANALYZING'), ('ANALYZING', 'SCHEDULING'),
>>              ('SCHEDULING', 'WAITING'), ('WAITING', 'ANALYZING'),
>>         ('ANALYZING',
>>         'GAME_OVER'), ('GAME_OVER', 'FAILURE')])
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine Traceback (most
>>         recent call last):
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/taskflow/engines/action_engine/engine.py",
>>              line 269, in run_iter
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine
>>              failure.Failure.reraise_if_any(memory.failures)
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/taskflow/types/failure.py",
>>              line 336, in reraise_if_any
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine
>>  failures[0].reraise()
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/taskflow/types/failure.py",
>>              line 343, in reraise
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine
>>           six.reraise(*self._exc_info)
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/taskflow/engines/action_engine/scheduler.py",
>>              line 94, in schedule
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine
>>              futures.add(scheduler.schedule(atom))
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/taskflow/engines/action_engine/scheduler.py",
>>              line 67, in schedule
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine     return
>>              self._task_action.schedule_execution(task)
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/taskflow/engines/action_engine/actions/task.py",
>>              line 99, in schedule_execution
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine
>>           self.change_state(task,
>>              states.RUNNING, progress=0.0)
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/taskflow/engines/action_engine/actions/task.py",
>>              line 67, in change_state
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine
>>              self._storage.set_atom_state(task.name <http://task.name>
>>         <http://task.name>, state)
>>
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/fasteners/lock.py",
>>              line 85, in wrapper
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine     return f(self,
>> *args,
>>              **kwargs)
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/taskflow/storage.py",
>>              line 486, in set_atom_state
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine
>>              self._with_connection(self._save_atom_detail, source, clone)
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/taskflow/storage.py",
>>              line 341, in _with_connection
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine     return
>> functor(conn,
>>              *args, **kwargs)
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/taskflow/storage.py",
>>              line 471, in _save_atom_detail
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine
>>
>>         original_atom_detail.update(conn.update_atom_details(atom_detail))
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/taskflow/persistence/backends/impl_sqlalchemy.py",
>>              line 427, in update_atom_details
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine     row =
>>         conn.execute(q).first()
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py",
>>              line 914, in execute
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine     return meth(self,
>>              multiparams, params)
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/sqlalchemy/sql/elements.py",
>>              line 323, in _execute_on_connection
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine     return
>>              connection._execute_clauseelement(self, multiparams, params)
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py",
>>              line 1003, in _execute_clauseelement
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine
>>              inline=len(distilled_params) > 1)
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File "<string>",
>>         line 1, in
>>         <lambda>
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/sqlalchemy/sql/elements.py",
>>              line 494, in compile
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine     return
>>              self._compiler(dialect, bind=bind, **kw)
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/sqlalchemy/sql/elements.py",
>>              line 500, in _compiler
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine     return
>>              dialect.statement_compiler(dialect, self, **kw)
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/sqlalchemy/sql/compiler.py",
>>              line 392, in __init__
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine
>>           Compiled.__init__(self,
>>              dialect, statement, **kwargs)
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/sqlalchemy/sql/compiler.py",
>>              line 190, in __init__
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine     self.string =
>>              self.process(self.statement, **compile_kwargs)
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/sqlalchemy/sql/compiler.py",
>>              line 213, in process
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine     return
>>              obj._compiler_dispatch(self, **kwargs)
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/sqlalchemy/sql/visitors.py",
>>              line 81, in _compiler_dispatch
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine     return meth(self,
>>         **kw)
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/sqlalchemy/sql/compiler.py",
>>              line 1579, in visit_select
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine     for name, column in
>>              select._columns_plus_names
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/sqlalchemy/sql/compiler.py",
>>              line 1347, in _label_select_column
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine
>>              add_to_result_map=add_to_result_map
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/celery/apps/worker.py",
>>              line 288, in _handle_request
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine     safe_say('worker:
>> {0}
>>              shutdown (MainProcess)'.format(how))
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine   File
>>
>> "/opt/nso/nso-1.1223-default/nfvo-0.8.0.dev1438/.venv/local/lib/python2.7/site-packages/celery/apps/worker.py",
>>              line 73, in safe_say
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine
>>           print('\n{0}'.format(msg),
>>              file=sys.__stderr__)
>>              2016-05-25 19:45:21.717 7119 TRACE
>>              taskflow.engines.action_engine.engine IOError: [Errno 5]
>>              Input/output error
>>              2016-05-25 19:45:21.717 7119 TRACE
>>         taskflow.engines.action_engine.engine
>>
>>              There could be a transient network issue which prevents
>>         taskflow
>>              from reaching the mysql node.
>>              Can you please suggest a graceful way of handling it and
>>         continue
>>              processing the execution?
>>
>>              Thanks,
>>              Kanthi
>>
>>
>>
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