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From vino yang <yanghua1...@gmail.com>
Subject Re: CompletedCheckpoints are getting Stale ( Flink 1.4.2 )
Date Fri, 31 Aug 2018 12:18:41 GMT
Hi Laura:

Perhaps this is possible because the path to the completed checkpoint on
HDFS does not have a hierarchical relationship to identify which job it
belongs to, it is just a fixed prefix plus a random string generated name.
My personal advice:

1) Verify it with a clean cluster (clean up the metadata that
Flink/Zookeeper/HDFS might confuse);
2) Verify the node and metadata information (/checkpoints/${jobID}/) on
ZooKeeper;
3) Observe whether there is relevant abnormal information in the log;

Thanks, vino.

Laura Uzcátegui <laura.uzcateguij@gmail.com> 于2018年8月31日周五 下午3:51写道:

> Hi Stephan and Vino,
>
> Thanks for the quick reply and hints.
>
> The configuration for the checkpoints that should remain is set to 1.
>
> Since this is a unbounded job run and I can't see it finishing, I suspect
> as we tear down the cluster every time we finish with the integration test
> being run, the completedCheckpoint doesn't get deleted, next when the
> integration test runs again it picks up from the latest completedCheckpoint
> but there is cases where that job doesn't run again therefore the
> completedCheckpoint gets staled. Is this something that could happen?
>
> Is there anyway to check by logging wether the job gets to Global Final
> State before we tear down the cluster?
>
> Cheers,
>
> Laura
>
> On Fri, 31 Aug 2018, 8:37 am Stephan Ewen, <sewen@apache.org> wrote:
>
>> Hi Laura!
>>
>> Vino had good pointers. There really should be no case in which this is
>> not cleaned up.
>>
>> Is this a bounded job that ends? Is it always the last of the bounded
>> job's checkpoints that remains?
>>
>> Best,
>> Stephan
>>
>>
>> On Fri, Aug 31, 2018 at 5:02 AM, vino yang <yanghua1127@gmail.com> wrote:
>>
>>> Hi Laura,
>>>
>>> First of all, Flink only keeps one completed checkpoint by default[1].
>>> You need to confirm whether your configuration is consistent with the
>>> number of files. If they are consistent, it is for other reasons:
>>>
>>> 1) The cleaning of the completed checkpoint is done by JM. You need to
>>> confirm whether it can access your file.[2]
>>> 2) JM will asynchronously clean up the metadata of the old completed
>>> checkpoint on the ZK with a background thread. After the cleanup is
>>> successful, it will clean the Checkpoint data. If the above reasons are
>>> excluded, then maybe you provide JM's log to help us confirm whether this
>>> is the reason. I think it is more appropriate to ping Till.[3]
>>>
>>> [1]:
>>> https://ci.apache.org/projects/flink/flink-docs-release-1.6/dev/stream/state/checkpointing.html#state-checkpoints-num-retained
>>> [2]:
>>> https://stackoverflow.com/questions/44928624/apache-flink-not-deleting-old-checkpoints
>>> [3]:
>>> https://github.com/apache/flink/blob/master/flink-runtime/src/main/java/org/apache/flink/runtime/zookeeper/ZooKeeperStateHandleStore.java#L437
>>>
>>> Thanks, vino.
>>>
>>> Laura Uzcátegui <laura.uzcateguij@gmail.com> 于2018年8月30日周四
下午10:52写道:
>>>
>>>> Hello,
>>>>
>>>>  At work, we are currently standing up a cluster with the following
>>>> configuration:
>>>>
>>>>
>>>>    - Flink version: 1.4.2
>>>>    - HA Enabled with Zookeeper
>>>>    - State backend : rocksDB
>>>>    - state.checkpoints.dir: hdfs://namenode:9000/flink/checkpoints
>>>>    - state.backend.rocksdb.checkpointdir:
>>>>    hdfs://namenode:9000/flink/checkpoints
>>>>    - *high-availability.storageDir*:
>>>>    hdfs://namenode:9000/flink/recovery
>>>>
>>>> We have also a job running with checkpointing enabled and without
>>>> externalized checkpoint.
>>>>
>>>> We run this job multiple times a day since it's run from our
>>>> integration-test pipeline, and we started noticing the folder
>>>> *high-availability.storageDir  *storing the completedCheckpoint files
>>>> is increasing constantly the number of files created, which is making us
>>>> wonder if there is no cleanup policy for the Filesystem when HA is enabled.
>>>>
>>>> Under what  circumstance would there be an ever increasing number of
>>>> completedCheckpoint files on the HA storage dir when there is only a single
>>>> job running over and over again ?
>>>>
>>>> Here is a list of what we are seeing accumulating over time and
>>>> actually reaching the maximum of files allowed on the Filesystem.
>>>>
>>>> completedCheckpoint00d86c01d8b9
>>>> completedCheckpoint00d86e9030a9
>>>> completedCheckpoint00d877b74355
>>>> completedCheckpoint00d87b3dd9ad
>>>> completedCheckpoint00d8815d9afd
>>>> completedCheckpoint00d88973195c
>>>> completedCheckpoint00d88b4792f2
>>>> completedCheckpoint00d890d499dc
>>>> completedCheckpoint00d91b00ada2
>>>>
>>>>
>>>> Cheers,
>>>>
>>>>
>>>> Laura U.
>>>>
>>>>
>>

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