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From "Driesprong, Fokko" <fo...@driesprong.frl>
Subject Re: Airflow looses track of Dag Tasks
Date Wed, 07 Mar 2018 14:39:00 GMT
Hi John,

There are some issues with Celery 4.1: https://github.com/
apache/incubator-airflow/pull/2806 Therefore we are still at 4.0. The
release cycle of Celery seems to be a bit stuck:
https://github.com/celery/celery/issues/4387

The only thing that I've experienced is that the task is begin scheduled
with Celery, but the feedback wasn't properly stored. This will be pushed
back to Postgres, but this wasn't working properly due config mismatches.
This caused Airflow to kick off the job, and dispatch it to Celery, but the
result of the job would never come back. Therefore it would exhaust the
number of slots quickly. All the Celery setups that I'm running are on 4.0
and appear to be running smoothly.

Cheers, Fokko

2018-03-07 15:29 GMT+01:00 Kamenik, John <jkamenik@fourv.com>:

> Nothing specific that I can see.
>
>
> I saw that the online that the docker image pins Celery to 4.0.2.
> https://github.com/puckel/docker-airflow.
>
>
> With the upgrade to Airflow 1.9 we upgraded all packages including
> Celery.  It was 4.1.  I have downgraded to Celery 4.0.2 and things appear
> to be more stable.
>
>
> With Celery 4.0.2 in place I have run 30 copies of the failing DAGs 30
> times each all in parallel and there were 2 failures total.  So I wouldn't
> say the issue is fixed completely, but certainly less bad then with Celery
> 4.1.  Down from a 33% failure rate to a 0.22% failure rate.
>
>
>
>
> - John K
>
> ________________________________
> From: Maxime Beauchemin <maximebeauchemin@gmail.com>
> Sent: Wednesday, March 7, 2018 1:20:05 AM
> To: dev@airflow.incubator.apache.org
> Subject: Re: Airflow looses track of Dag Tasks
>
> Notice: This message originated outside of SRC.
>
> Anything else specific? I heard SubDags can have issues under certain
> conditions, is this happening inside SubDags? Anybody else in the community
> has experienced anything like this on 1.9?
>
> On Mon, Mar 5, 2018 at 9:13 AM, Kamenik, John <jkamenik@fourv.com> wrote:
>
> > Airflow scheduler, flower, and webserver are within a statefulset.
> > Workers are in another statefulset.  Dags are shared between scheduler
> and
> > workers via NFS; CeleryExecuter.
> >
> >
> > The issue happens quite often.  There are hundreds of DAGs that run every
> > day.  Every DAG has failed at least once; most fail at least once every 3
> > days.  On average about 1/3 to 1/2 of all dag runs fail in a given day.
> No
> > pattern of failure that we can see; other then it looks like Celery
> looses
> > track of the task or the Task details in the database get corrupt.
> >
> >
> > There is no obvious error in the output for any of the services:
> postgres,
> > redis, scheduler, flower, or workers.  If we do find the worker logs
> > (sometimes we cannot) then it usually indicates that the script called
> runs
> > to completion and is a success.
> >
> >
> > Not sure where the issue might be.
> >
> >
> >
> >
> > - John K
> >
> > ________________________________
> > From: Maxime Beauchemin <maximebeauchemin@gmail.com>
> > Sent: Monday, March 5, 2018 11:57:16 AM
> > To: dev@airflow.incubator.apache.org
> > Subject: Re: Airflow looses track of Dag Tasks
> >
> > Notice: This message originated outside of SRC.
> >
> > Are you using the Kubernetes executor or running Airflow worker(s) inside
> > persistent pod?
> >
> > How often does that happen? Does it randomly occur on any task, any
> pattern
> > there?
> >
> > Max
> >
> > On Fri, Mar 2, 2018 at 7:09 AM, Kamenik, John <jkamenik@fourv.com>
> wrote:
> >
> > > I have an airflow 1.9 cluster setup on kubernetes and I have an issue
> > > where a random DAG Task shows as fail because it appears that Airflow
> has
> > > lost track of it.  The cluster consists of a database, redis store,
> > > scheduler, and 14 workers.
> > >
> > >
> > > What happens is the task starts as normal, runs, and exits, but instead
> > of
> > > status being written the Operator, State Date, Job ID, and Hostname are
> > > erased.   Shortly there after an endtime is added and the state is set
> to
> > > failed.
> > >
> > >
> > > Given the hostname is erased I to brute force find the logs of the
> worker
> > > that executed the task.  If I can find the Task logs it indicates the
> > > command (BashOperator) ran to completion and exited cleanly.  I don't
> see
> > > any errors in the airflow scheduler or any workers that would indicate
> > any
> > > issues.  I am not sure what else to debug.
> > >
> > >
> > >
> > >
> > > - John K
> > >
> >
>

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