I think you should use nfs, which is easily to be deployed unlike hdfs.
The state is written and read by TM.
ZK is used to record some meta data of the checkpoint, such as the ckpt
file path.
Finally, I don't think your job can be recovered normally if you are not
running with a shared storage.
Afek, Ifat (Nokia - IL/Kfar Sava) <ifat.a...@nokia.com> 于2022年3月2日周三
16:16写道：
> Thanks.
>
>
>
> At the moment I’m running without a shared file storage, and I’m trying to
> better understand the recovery process.
>
>
>
> The behavior I see is as follows:
>
> - The job manager identifies the task manager’s failure and tries to
> restart
> - The job manager fails to find the checkpoint. Looking inside the
> pods, I see that the checkpoints are stored in the task manager (after it
> was restarted by k8s), but not in the job manager.
> - The job manager gives up after a few retries
> - The job manager succeeds to get the checkpoint from Zookeeper
> - The job manager successfully restarts the task manager
>
>
>
> I’ll be happy if you can help me understand the
> behavior:
>
> Who is responsible for writing and then reading the checkpoints data? The
> task manager or the job manager? Should the job manager and task manager
> access the same storage, so the job manager can retrieve the task manager
> checkpoints?
>
> What is the Zookeeper’s part in the story?
>
> And is there a way for me to improve this process / shorten the time it
> takes ?
>
>
>
> The relevant section in my log:
>
>
>
> java.lang.Exception: Exception while creating StreamOperatorStateContext.
>
> at
> org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.streamOperatorStateContext(StreamTaskStateInitializerImpl.java:254)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.streaming.api.operators.AbstractStreamOperator.initializeState(AbstractStreamOperator.java:272)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.streaming.runtime.tasks.OperatorChain.initializeStateAndOpenOperators(OperatorChain.java:441)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.streaming.runtime.tasks.StreamTask.restoreGates(StreamTask.java:585)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.streaming.runtime.tasks.StreamTaskActionExecutor$1.call(StreamTaskActionExecutor.java:55)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.streaming.runtime.tasks.StreamTask.executeRestore(StreamTask.java:565)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.streaming.runtime.tasks.StreamTask.runWithCleanUpOnFail(StreamTask.java:650)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.streaming.runtime.tasks.StreamTask.restore(StreamTask.java:540)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at org.apache.flink.runtime.taskmanager.Task.doRun(Task.java:759)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at org.apache.flink.runtime.taskmanager.Task.run(Task.java:566)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at java.lang.Thread.run(Unknown Source) ~[?:?]
>
> Caused by: org.apache.flink.util.FlinkException: Could not restore
> operator state backend for
> DoFnOperator_764f1681beaffc88f686a6a1532b6deb_(1/1) from any of the 1
> provided restore options.
>
> at
> org.apache.flink.streaming.api.operators.BackendRestorerProcedure.createAndRestore(BackendRestorerProcedure.java:160)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.operatorStateBackend(StreamTaskStateInitializerImpl.java:285)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.streamOperatorStateContext(StreamTaskStateInitializerImpl.java:173)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> ... 10 more
>
> Caused by: org.apache.flink.runtime.state.BackendBuildingException: Failed
> when trying to restore operator state backend
>
> at
> org.apache.flink.runtime.state.DefaultOperatorStateBackendBuilder.build(DefaultOperatorStateBackendBuilder.java:83)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.runtime.state.hashmap.HashMapStateBackend.createOperatorStateBackend(HashMapStateBackend.java:148)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.lambda$operatorStateBackend$0(StreamTaskStateInitializerImpl.java:276)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.streaming.api.operators.BackendRestorerProcedure.attemptCreateAndRestore(BackendRestorerProcedure.java:168)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.streaming.api.operators.BackendRestorerProcedure.createAndRestore(BackendRestorerProcedure.java:135)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.operatorStateBackend(StreamTaskStateInitializerImpl.java:285)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.streamOperatorStateContext(StreamTaskStateInitializerImpl.java:173)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> ... 10 more
>
> Caused by: java.io.FileNotFoundException:
> /flink_state/checkpoints/523f9e48274186bb97c13e3c2213be0e/chk-8/07e16ec0-0415-4aff-8981-5305e2b618f6
> (No such file or directory)
>
> at java.io.FileInputStream.open0(Native Method) ~[?:?]
>
> at java.io.FileInputStream.open(Unknown Source) ~[?:?]
>
> at java.io.FileInputStream.<init>(Unknown Source) ~[?:?]
>
> at
> org.apache.flink.core.fs.local.LocalDataInputStream.<init>(LocalDataInputStream.java:50)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.core.fs.local.LocalFileSystem.open(LocalFileSystem.java:134)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.core.fs.SafetyNetWrapperFileSystem.open(SafetyNetWrapperFileSystem.java:87)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.runtime.state.filesystem.FileStateHandle.openInputStream(FileStateHandle.java:68)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.runtime.state.OperatorStreamStateHandle.openInputStream(OperatorStreamStateHandle.java:66)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.runtime.state.OperatorStateRestoreOperation.restore(OperatorStateRestoreOperation.java:72)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.runtime.state.DefaultOperatorStateBackendBuilder.build(DefaultOperatorStateBackendBuilder.java:80)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.runtime.state.hashmap.HashMapStateBackend.createOperatorStateBackend(HashMapStateBackend.java:148)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.lambda$operatorStateBackend$0(StreamTaskStateInitializerImpl.java:276)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.streaming.api.operators.BackendRestorerProcedure.attemptCreateAndRestore(BackendRestorerProcedure.java:168)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.streaming.api.operators.BackendRestorerProcedure.createAndRestore(BackendRestorerProcedure.java:135)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.operatorStateBackend(StreamTaskStateInitializerImpl.java:285)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> at
> org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.streamOperatorStateContext(StreamTaskStateInitializerImpl.java:173)
> ~[flink-dist_2.11-1.13.5.jar:1.13.5]
>
> ... 10 more
>
>
>
> 2022-02-24 12:18:57,786 INFO
> org.apache.flink.runtime.executiongraph.failover.flip1.RestartPipelinedRegionFailoverStrategy
> [] - Calculating tasks to restart to recover the failed task
> 55f0dd6ce96daa34877e5b041baadee7_0.
>
> 2022-02-24 12:18:57,786 INFO
> org.apache.flink.runtime.executiongraph.failover.flip1.RestartPipelinedRegionFailoverStrategy
> [] - 2 tasks should be restarted to recover the failed task
> 55f0dd6ce96daa34877e5b041baadee7_0.
>
> 2022-02-24 12:18:57,786 INFO
> org.apache.flink.runtime.executiongraph.ExecutionGraph
> [] - Job AmfEventsToCentral (523f9e48274186bb97c13e3c2213be0e)
> switched from state RUNNING to RESTARTING.
>
> 2022-02-24 12:18:57,786 INFO
> org.apache.flink.runtime.executiongraph.ExecutionGraph
> [] - Source:
> readFromKafka/KafkaIO.Read.ReadFromKafkaViaUnbounded/Read(KafkaUnboundedSource)
> -> Flat Map ->
> convertAmfNotificationsToEvents/ParMultiDo(ConvertAmfNotificationsToEvents)
> -> WriteToAvro/MapElements/Map/ParMultiDo(Anonymous) ->
> WriteToAvro/PubsubUnboundedSink/Output Serialized PubsubMessage
> Proto/Map/ParMultiDo(Anonymous) ->
> WriteToAvro/PubsubUnboundedSink/PubsubUnboundedSink.PubsubSink/PubsubUnboundedSink.Window/Window.Assign.out
> ->
> WriteToAvro/PubsubUnboundedSink/PubsubUnboundedSink.PubsubSink/PubsubUnboundedSink.Shard/ParMultiDo(Shard)
> -> ToBinaryKeyedWorkItem (1/1) (cc9e2f14636aae06879e455656eab3ca) switched
> from INITIALIZING to CANCELING.
>
> 2022-02-24 12:18:57,853 INFO
> org.apache.flink.runtime.executiongraph.ExecutionGraph
> [] - Source:
> readFromKafka/KafkaIO.Read.ReadFromKafkaViaUnbounded/Read(KafkaUnboundedSource)
> -> Flat Map ->
> convertAmfNotificationsToEvents/ParMultiDo(ConvertAmfNotificationsToEvents)
> -> WriteToAvro/MapElements/Map/ParMultiDo(Anonymous) ->
> WriteToAvro/PubsubUnboundedSink/Output Serialized PubsubMessage
> Proto/Map/ParMultiDo(Anonymous) ->
> WriteToAvro/PubsubUnboundedSink/PubsubUnboundedSink.PubsubSink/PubsubUnboundedSink.Window/Window.Assign.out
> ->
> WriteToAvro/PubsubUnboundedSink/PubsubUnboundedSink.PubsubSink/PubsubUnboundedSink.Shard/ParMultiDo(Shard)
> -> ToBinaryKeyedWorkItem (1/1) (cc9e2f14636aae06879e455656eab3ca) switched
> from CANCELING to CANCELED.
>
> 2022-02-24 12:18:57,854 INFO
> org.apache.flink.runtime.resourcemanager.slotmanager.DeclarativeSlotManager
> [] - Clearing resource requirements of job 523f9e48274186bb97c13e3c2213be0e
>
> 2022-02-24 12:19:52,032 INFO
> org.apache.flink.runtime.jobmaster.slotpool.DefaultDeclarativeSlotPool
> [] - Releasing slot [28162b793b27f93fe4463e330e4cbc33].
>
> 2022-02-24 12:20:16,702 INFO
> org.apache.flink.runtime.executiongraph.ExecutionGraph
> [] - Job AmfEventsToCentral (523f9e48274186bb97c13e3c2213be0e)
> switched from state RESTARTING to RUNNING.
>
> 2022-02-24 12:20:16,704 INFO
> org.apache.flink.runtime.checkpoint.DefaultCompletedCheckpointStore
> [] - Recovering checkpoints from
> ZooKeeperStateHandleStore{namespace='flink/default/checkpoints/523f9e48274186bb97c13e3c2213be0e'}.
>
> 2022-02-24 12:20:16,712 INFO
> org.apache.flink.runtime.checkpoint.DefaultCompletedCheckpointStore
> [] - Found 1 checkpoints in
> ZooKeeperStateHandleStore{namespace='flink/default/checkpoints/523f9e48274186bb97c13e3c2213be0e'}.
>
> 2022-02-24 12:20:16,712 INFO
> org.apache.flink.runtime.checkpoint.DefaultCompletedCheckpointStore
> [] - All 1 checkpoints found are already downloaded.
>
> 2022-02-24 12:20:16,712 INFO
> org.apache.flink.runtime.checkpoint.CheckpointCoordinator [] -
> Restoring job 523f9e48274186bb97c13e3c2213be0e from Checkpoint 8 @
> 1645704948497 for 523f9e48274186bb97c13e3c2213be0e located at
> file:/flink_state/checkpoints/523f9e48274186bb97c13e3c2213be0e/chk-8.
>
> 2022-02-24 12:20:16,713 INFO
> org.apache.flink.runtime.checkpoint.CheckpointCoordinator [] - No
> master state to restore
>
> 2
>
>
>
>
>
> Thanks,
>
> Ifat
>
>
>
> *From: *yidan zhao <hinobl...@gmail.com>
> *Date: *Wednesday, 2 March 2022 at 4:08
> *To: *"Afek, Ifat (Nokia - IL/Kfar Sava)" <ifat.a...@nokia.com>
> *Cc: *zhlonghong <zhlongh...@gmail.com>, "user@flink.apache.org" <
> user@flink.apache.org>
> *Subject: *Re: Flink job recovery after task manager failure
>
>
>
> State backend can be set as hashMap or rocksDB.
>
> Checkpoint storage must be a shared file system(nfs or hdfs or something
> else).
>
>
>
> Afek, Ifat (Nokia - IL/Kfar Sava) <ifat.a...@nokia.com> 于2022年3月2日周三 05:55
> 写道：
>
> Hi,
>
>
>
> I’m trying to understand the guidelines for task manager recovery.
>
> From what I see in the documentation, state backend can be set as in
> memory / file system / rocksdb, and the checkpoint storage requires a
> shared file system for both file system and rocksdb. Is that correct? Must
> the file system be shared between the task managers and job managers? Is
> there another option?
>
>
>
> Thanks,
>
> Ifat
>
>
>
> *From: *Zhilong Hong <zhlongh...@gmail.com>
> *Date: *Thursday, 24 February 2022 at 19:58
> *To: *"Afek, Ifat (Nokia - IL/Kfar Sava)" <ifat.a...@nokia.com>
> *Cc: *"user@flink.apache.org" <user@flink.apache.org>
> *Subject: *Re: Flink job recovery after task manager failure
>
>
>
> Hi, Afek
>
>
>
> I've read the log you provided. Since you've set the value of
> restart-strategy to be exponential-delay and the value
> of restart-strategy.exponential-delay.initial-backoff is 10s, everytime a
> failover is triggered, the JobManager will have to wait for 10 seconds
> before it restarts the job.If you'd prefer a quicker restart, you could
> change the restart strategy to fixed-delay and set a small value for
> restart-strategy.fixed-delay.delay.
>
>
>
> Furthermore, there are two more failovers that happened during the
> initialization of recovered tasks. During the initialization of a task, it
> will try to recover the states from the last valid checkpoint. A
> FileNotFound exception happens during the recovery process. I'm not quite
> sure the reason. Since the recovery succeeds after two failovers, I think
> maybe it's because the local disks of your cluster are not stable.
>
>
>
> Sincerely,
>
> Zhilong
>
>
>
> On Thu, Feb 24, 2022 at 9:04 PM Afek, Ifat (Nokia - IL/Kfar Sava) <
> ifat.a...@nokia.com> wrote:
>
> Thanks Zhilong.
>
>
>
> The first launch of our job is fast, I don’t think that’s the issue. I see
> in flink job manager log that there were several exceptions during the
> restart, and the task manager was restarted a few times until it was
> stabilized.
>
>
>
> You can find the log here:
>
> jobmanager-log.txt.gz
> <https://nokia-my.sharepoint.com/:u:/p/ifat_afek/EUsu4rb_-BpNrkpvSwzI-vgBtBO9OQlIm0CHtW0gsZ7Gqg?email=zhlonghong%40gmail.com&e=ww5Idt>
>
>
>
> Thanks,
>
> Ifat
>
>
>
> *From: *Zhilong Hong <zhlongh...@gmail.com>
> *Date: *Wednesday, 23 February 2022 at 19:38
> *To: *"Afek, Ifat (Nokia - IL/Kfar Sava)" <ifat.a...@nokia.com>
> *Cc: *"user@flink.apache.org" <user@flink.apache.org>
> *Subject: *Re: Flink job recovery after task manager failure
>
>
>
> Hi, Afek!
>
>
>
> When a TaskManager is killed, JobManager will not be acknowledged until a
> heartbeat timeout happens. Currently, the default value of
> heartbeat.timeout is 50 seconds [1]. That's why it takes more than 30
> seconds for Flink to trigger a failover. If you'd like to shorten the time
> a failover is triggered in this situation, you could decrease the value of
> heartbeat.timeout in flink-conf.yaml. However, if the value is set too
> small, heartbeat timeouts will happen more frequently and the cluster will
> be unstable. As FLINK-23403 [2] mentions, if you are using Flink 1.14 or
> 1.15, you could try to set the value to 10s.
>
>
>
> You mentioned that it takes 5-6 minutes to restart the jobs. It seems a
> bit weird. How long does it take to deploy your job for a brand new launch?
> You could compact and upload the log of JobManager to Google Drive or
> OneDrive and attach the sharing link. Maybe we can find out what happens
> via the log.
>
>
>
> Sincerely,
>
> Zhilong
>
>
>
> [1]
> https://nightlies.apache.org/flink/flink-docs-master/docs/deployment/config/#heartbeat-timeout
>
> [2] https://issues.apache.org/jira/browse/FLINK-23403
>
>
>
> On Thu, Feb 24, 2022 at 12:25 AM Afek, Ifat (Nokia - IL/Kfar Sava) <
> ifat.a...@nokia.com> wrote:
>
> Hi,
>
>
>
> I am trying to use Flink checkpoints solution in order to support task
> manager recovery.
>
> I’m running flink using beam with filesystem storage and the following
> parameters:
>
> checkpointingInterval=30000
>
> checkpointingMode=EXACTLY_ONCE.
>
>
>
> What I see is that if I kill a task manager pod, it takes flink about 30
> seconds to identify the failure and another 5-6 minutes to restart the jobs.
>
> Is there a way to shorten the downtime? What is an expected downtime in
> case the task manager is killed, until the jobs are recovered? Are there
> any best practices for handling it? (e.g. different configuration
> parameters)
>
>
>
> Thanks,
>
> Ifat
>
>
>
>
