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From Ufuk Celebi <...@apache.org>
Subject Re: Flink Checkpoint on yarn
Date Wed, 16 Mar 2016 17:04:28 GMT
Hey Simone,

from the logs it looks like multiple jobs have been submitted to the
cluster, not just one. The different files correspond to different
jobs recovering. The filtered logs show three jobs running/recovering
(with IDs 10d8ccae6e87ac56bf763caf4bc4742f,
124f29322f9026ac1b35435d5de9f625, 7f280b38065eaa6335f5c3de4fc82547).

Did you manually re-submit the job after killing a job manager?

Regarding the counts, it can happen that they are rolled back to a
previous consistent state if the checkpoint was not completed yet
(including the write to ZooKeeper). In that case the job state will be
rolled back to an earlier consistent state.

Can you please share the complete job manager logs of your program?
The most helpful thing will be to have a log for each started job
manager container. I don't know if that is easily possible.

– Ufuk

On Wed, Mar 16, 2016 at 4:12 PM, Simone Robutti
<simone.robutti@radicalbit.io> wrote:
> This is the log filtered to check messages from
> ZooKeeperCompletedCheckpointStore.
>
> https://gist.github.com/chobeat/0222b31b87df3fa46a23
>
> It looks like it finds only a checkpoint but I'm not sure if the different
> hashes and IDs of the checkpoints are meaningful or not.
>
>
>
> 2016-03-16 15:33 GMT+01:00 Ufuk Celebi <uce@apache.org>:
>>
>> Can you please have a look into the JobManager log file and report
>> which checkpoints are restored? You should see messages from
>> ZooKeeperCompletedCheckpointStore like:
>> - Found X checkpoints in ZooKeeper
>> - Initialized with X. Removing all older checkpoints
>>
>> You can share the complete job manager log file as well if you like.
>>
>> – Ufuk
>>
>> On Wed, Mar 16, 2016 at 2:50 PM, Simone Robutti
>> <simone.robutti@radicalbit.io> wrote:
>> > Hello,
>> >
>> > I'm testing the checkpointing functionality with hdfs as a backend.
>> >
>> > For what I can see it uses different checkpointing files and resume the
>> > computation from different points and not from the latest available.
>> > This is
>> > to me an unexpected behaviour.
>> >
>> > I log every second, for every worker, a counter that is increased by 1
>> > at
>> > each step.
>> >
>> > So for example on node-1 the count goes up to 5, then I kill a job
>> > manager
>> > or task manager and it resumes from 5 or 4 and it's ok. The next time I
>> > kill
>> > a job manager the count is at 15 and it resumes at 14 or 15. Sometimes
>> > it
>> > may happen that at a third kill the work resumes at 4 or 5 as if the
>> > checkpoint resumed the second time wasn't there.
>> >
>> > Once I even saw it jump forward: the first kill is at 10 and it resumes
>> > at
>> > 9, the second kill is at 70 and it resumes at 9, the third kill is at 15
>> > but
>> > it resumes at 69 as if it resumed from the second kill checkpoint.
>> >
>> > This is clearly inconsistent.
>> >
>> > Also, in the logs I can find that sometimes it uses a checkpoint file
>> > different from the previous, consistent resume.
>> >
>> > What am I doing wrong? Is it a known bug?
>
>

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