hi, 1. I took a closer look at the relevant code about RocksDBIncrementalRestoreOperation::restoreInstanceDirectoryFromPath. And I did some verification. I found this problem is likely related to file system connection restrictions. At first I was worried that my hdfs would be overloaded due to a large number of connections, so I configured the following related parameters：
fs.<scheme>.limit.total: (number, 0/-1 mean no limit)fs.<scheme>.limit.input: (number, 0/-1 mean no limit)fs.<scheme>.limit.output: (number, 0/-1 mean no limit)fs.<scheme>.limit.timeout: (milliseconds, 0 means infinite)fs.<scheme>.limit.stream-timeout: (milliseconds, 0 means infinite) Since I configured the above configuration, this problem has begun to appear! When I removed the above configuration, the problem disappeared.I think that when flink is configured with file system connection restrictions, the mechanism for recovering from checkpoint needs to be improved. Jobs can recover from checkpoints more slowly with file system connection restrictions, rather than failing directly because of the above exceptions. 2. After the job has been running for a long time, if the state data stored in the state backend (such as hdfs) is lost for some reason, what other ways can quickly restore this state data back quickly, for example, through some kind of offline task is to quickly recover state data from offline data, so that streaming jobs can be launched from this recovered state data. Best Ben Ben Yan <yan.xiao.bin.m...@gmail.com> 于2018年12月8日周六 上午11:08写道： > I hava already tested it. > > [root@node ~]#ll > /mnt/yarn/local/usercache/yarn/appcache/application_1544101169829_0038/ > total 32 > drwxr-xr-x 2 yarn hadoop 4096 Dec 8 02:29 > blobStore-273cf1a6-0f98-4c86-801e-5d76fef66a58 > drwxr-xr-x 2 yarn hadoop 4096 Dec 8 02:29 > blobStore-992562a5-f42f-43f7-90de-a415b4dcd398 > drwx--x--- 4 yarn hadoop 4096 Dec 8 02:29 > container_e73_1544101169829_0038_01_000059 > drwx--x--- 13 yarn hadoop 4096 Dec 8 02:29 filecache > drwxr-xr-x 2 yarn hadoop 4096 Dec 8 02:29 > flink-dist-cache-6d8dab0c-4034-4bbe-a9b9-b524cf6856e3 > drwxr-xr-x 8 yarn hadoop 4096 Dec 8 02:29 > flink-io-6fba8471-4d84-4c13-9e3c-ef3891b366f0 > drwxr-xr-x 4 yarn hadoop 4096 Dec 8 02:29 localState > drwxr-xr-x 2 yarn hadoop 4096 Dec 8 02:29 > rocksdb-lib-7ef4471db8d3b8c1bdcfa4dba4d95a36 > > And the derectory "flink-io-6fba8471-4d84-4c13-9e3c-ef3891b366f0" does not > exist. > > [root@node ~]#ll > /mnt/yarn/local/usercache/yarn/appcache/application_1544101169829_0038/ > total 12 > drwx--x--- 13 yarn hadoop 4096 Dec 8 02:29 filecache > drwxr-xr-x 2 yarn hadoop 4096 Dec 8 02:53 localState > drwxr-xr-x 2 yarn hadoop 4096 Dec 8 02:53 > rocksdb-lib-7ef4471db8d3b8c1bdcfa4dba4d95a36 > > Ben Yan <yan.xiao.bin.m...@gmail.com> 于2018年12月8日周六 上午12:23写道： > >> Thank you for your advice! I will check this out next, and I will sync >> the information at any time with new progress. >> >> Stefan Richter <s.rich...@data-artisans.com> 于2018年12月8日周六 上午12:05写道： >> >>> I think then you need to investigate what goes wrong >>> in RocksDBIncrementalRestoreOperation::restoreInstanceDirectoryFromPath. If >>> you look at the code it lists the files in a directory and tries to hard >>> link them into another directory, and I would only expect to see the >>> mentioned exception if the original file that we try to link does not >>> exist. However, imo it must exist because we list it in the directory right >>> before the link attempt and Flink is not delete anything in the meantime. >>> So the question is, why can a file that was listed before just suddenly >>> disappear when it is hard linked? The only potential problem could be in >>> the path transformations and concatenations, but they look good to me and >>> also pass all tests, including end-to-end tests that do exactly such a >>> restore. I suggest to either observe the created files and what happens >>> with the one that is mentioned in the exception or introduce debug logging >>> in the code, in particular a check if the listed file (the link target) >>> does exist before linking, which it should in my opinion because it is >>> listed in the directory. >>> >>> On 7. Dec 2018, at 16:33, Ben Yan <yan.xiao.bin.m...@gmail.com> wrote: >>> >>> The version of the recovered checkpoint is also 1.7.0 . >>> >>> Stefan Richter <s.rich...@data-artisans.com> 于2018年12月7日周五 下午11:06写道： >>> >>>> Just to clarify, the checkpoint from which you want to resume in 1.7, >>>> was that taken by 1.6 or by 1.7? So far this is a bit mysterious because it >>>> says FileNotFound, but the whole iteration is driven by listing the >>>> existing files. Can you somehow monitor which files and directories are >>>> created during the restore attempt? >>>> >>>> On 7. Dec 2018, at 15:53, Ben Yan <yan.xiao.bin.m...@gmail.com> wrote: >>>> >>>> hi ，Stefan >>>> >>>> Thank you for your explanation. I used flink1.6.2, which is without any >>>> problems. I have tested it a few times with version 1.7.0, but every time I >>>> resume from the checkpoint, the job will show the exception I showed >>>> earlier, which will make the job unrecoverable.And I checked all the logs, >>>> except for this exception, there are no other exceptions. >>>> >>>> The following is all the logs when an exception occurs: >>>> >>>> 2018-12-06 22:53:41,282 INFO >>>> org.apache.flink.runtime.executiongraph.ExecutionGraph - >>>> KeyedProcess (120/138) (25ab0c8d0bc657860b766fa4c8d85a42) switched from >>>> DEPLOYING to RUNNING. >>>> >>>> 2018-12-06 22:53:41,285 INFO >>>> org.apache.flink.runtime.executiongraph.ExecutionGraph - >>>> KeyedProcess (2/138) (f770d22a976463d90fb4349d1c8521b8) switched from >>>> RUNNING to FAILED. >>>> java.lang.Exception: Exception while creating StreamOperatorStateContext. >>>> at >>>> org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.streamOperatorStateContext(StreamTaskStateInitializerImpl.java:195) >>>> at >>>> org.apache.flink.streaming.api.operators.AbstractStreamOperator.initializeState(AbstractStreamOperator.java:250) >>>> at >>>> org.apache.flink.streaming.runtime.tasks.StreamTask.initializeState(StreamTask.java:738) >>>> at >>>> org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:289) >>>> at org.apache.flink.runtime.taskmanager.Task.run(Task.java:704) >>>> at java.lang.Thread.run(Thread.java:748) >>>> Caused by: org.apache.flink.util.FlinkException: Could not restore keyed >>>> state backend for >>>> KeyedProcessOperator_e528d5d97ea2d7cefbcf6ff5b46354d5_(2/138) from any of >>>> the 1 provided restore options. >>>> at >>>> org.apache.flink.streaming.api.operators.BackendRestorerProcedure.createAndRestore(BackendRestorerProcedure.java:137) >>>> at >>>> org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.keyedStatedBackend(StreamTaskStateInitializerImpl.java:284) >>>> at >>>> org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.streamOperatorStateContext(StreamTaskStateInitializerImpl.java:135) >>>> ... 5 more >>>> Caused by: java.nio.file.NoSuchFileException: >>>> /mnt/yarn/local/usercache/yarn/appcache/application_1544101169829_0004/flink-io-133c16c5-4565-4014-b769-2a978af8e772/job_6e40c9381aa12f69b6ac182c91d993f5_op_KeyedProcessOperator_e528d5d97ea2d7cefbcf6ff5b46354d5__2_138__uuid_ab38b75f-77d7-4124-a410-6444b35d232d/db/000495.sst >>>> -> >>>> /mnt/yarn/local/usercache/yarn/appcache/application_1544101169829_0004/flink-io-133c16c5-4565-4014-b769-2a978af8e772/job_6e40c9381aa12f69b6ac182c91d993f5_op_KeyedProcessOperator_e528d5d97ea2d7cefbcf6ff5b46354d5__2_138__uuid_ab38b75f-77d7-4124-a410-6444b35d232d/cf45eae8-d5d4-4f04-8bf9-8d54ac078769/000495.sst >>>> at >>>> sun.nio.fs.UnixException.translateToIOException(UnixException.java:86) >>>> at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:102) >>>> at >>>> sun.nio.fs.UnixFileSystemProvider.createLink(UnixFileSystemProvider.java:476) >>>> at java.nio.file.Files.createLink(Files.java:1086) >>>> at >>>> org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend$RocksDBIncrementalRestoreOperation.restoreInstanceDirectoryFromPath(RocksDBKeyedStateBackend.java:1238) >>>> at >>>> org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend$RocksDBIncrementalRestoreOperation.restoreLocalStateIntoFullInstance(RocksDBKeyedStateBackend.java:1186) >>>> at >>>> org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend$RocksDBIncrementalRestoreOperation.restoreWithoutRescaling(RocksDBKeyedStateBackend.java:916) >>>> at >>>> org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend$RocksDBIncrementalRestoreOperation.restore(RocksDBKeyedStateBackend.java:864) >>>> at >>>> org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend.restore(RocksDBKeyedStateBackend.java:525) >>>> at >>>> org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend.restore(RocksDBKeyedStateBackend.java:147) >>>> at >>>> org.apache.flink.streaming.api.operators.BackendRestorerProcedure.attemptCreateAndRestore(BackendRestorerProcedure.java:151) >>>> at >>>> org.apache.flink.streaming.api.operators.BackendRestorerProcedure.createAndRestore(BackendRestorerProcedure.java:123) >>>> ... 7 more >>>> 2018-12-06 22:53:41,286 INFO >>>> org.apache.flink.runtime.executiongraph.ExecutionGraph - Job >>>> Flink-Job-Offline (6e40c9381aa12f69b6ac182c91d993f5) switched from state >>>> RUNNING to FAILING. >>>> java.lang.Exception: Exception while creating StreamOperatorStateContext. >>>> at >>>> org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.streamOperatorStateContext(StreamTaskStateInitializerImpl.java:195) >>>> at >>>> org.apache.flink.streaming.api.operators.AbstractStreamOperator.initializeState(AbstractStreamOperator.java:250) >>>> at >>>> org.apache.flink.streaming.runtime.tasks.StreamTask.initializeState(StreamTask.java:738) >>>> at >>>> org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:289) >>>> at org.apache.flink.runtime.taskmanager.Task.run(Task.java:704) >>>> at java.lang.Thread.run(Thread.java:748) >>>> Caused by: org.apache.flink.util.FlinkException: Could not restore keyed >>>> state backend for >>>> KeyedProcessOperator_e528d5d97ea2d7cefbcf6ff5b46354d5_(2/138) from any of >>>> the 1 provided restore options. >>>> at >>>> org.apache.flink.streaming.api.operators.BackendRestorerProcedure.createAndRestore(BackendRestorerProcedure.java:137) >>>> at >>>> org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.keyedStatedBackend(StreamTaskStateInitializerImpl.java:284) >>>> at >>>> org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.streamOperatorStateContext(StreamTaskStateInitializerImpl.java:135) >>>> ... 5 more >>>> Caused by: java.nio.file.NoSuchFileException: >>>> /mnt/yarn/local/usercache/yarn/appcache/application_1544101169829_0004/flink-io-133c16c5-4565-4014-b769-2a978af8e772/job_6e40c9381aa12f69b6ac182c91d993f5_op_KeyedProcessOperator_e528d5d97ea2d7cefbcf6ff5b46354d5__2_138__uuid_ab38b75f-77d7-4124-a410-6444b35d232d/db/000495.sst >>>> -> >>>> /mnt/yarn/local/usercache/yarn/appcache/application_1544101169829_0004/flink-io-133c16c5-4565-4014-b769-2a978af8e772/job_6e40c9381aa12f69b6ac182c91d993f5_op_KeyedProcessOperator_e528d5d97ea2d7cefbcf6ff5b46354d5__2_138__uuid_ab38b75f-77d7-4124-a410-6444b35d232d/cf45eae8-d5d4-4f04-8bf9-8d54ac078769/000495.sst >>>> at >>>> sun.nio.fs.UnixException.translateToIOException(UnixException.java:86) >>>> at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:102) >>>> at >>>> sun.nio.fs.UnixFileSystemProvider.createLink(UnixFileSystemProvider.java:476) >>>> at java.nio.file.Files.createLink(Files.java:1086) >>>> at >>>> org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend$RocksDBIncrementalRestoreOperation.restoreInstanceDirectoryFromPath(RocksDBKeyedStateBackend.java:1238) >>>> at >>>> org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend$RocksDBIncrementalRestoreOperation.restoreLocalStateIntoFullInstance(RocksDBKeyedStateBackend.java:1186) >>>> at >>>> org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend$RocksDBIncrementalRestoreOperation.restoreWithoutRescaling(RocksDBKeyedStateBackend.java:916) >>>> at >>>> org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend$RocksDBIncrementalRestoreOperation.restore(RocksDBKeyedStateBackend.java:864) >>>> at >>>> org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend.restore(RocksDBKeyedStateBackend.java:525) >>>> at >>>> org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend.restore(RocksDBKeyedStateBackend.java:147) >>>> at >>>> org.apache.flink.streaming.api.operators.BackendRestorerProcedure.attemptCreateAndRestore(BackendRestorerProcedure.java:151) >>>> at >>>> org.apache.flink.streaming.api.operators.BackendRestorerProcedure.createAndRestore(BackendRestorerProcedure.java:123) >>>> ... 7 more >>>> 2018-12-06 22:53:41,287 INFO >>>> org.apache.flink.runtime.executiongraph.ExecutionGraph - Source: >>>> topic.rate (1/16) (5637f1c3568ca7c29db002e579c05546) switched from RUNNING >>>> to CANCELING. >>>> >>>> >>>> >>>> Best, >>>> Ben >>>> >>>> Stefan Richter <s.rich...@data-artisans.com> 于2018年12月7日周五 下午10:00写道： >>>> >>>>> Hi, >>>>> >>>>> From what I can see in the log here, it looks like your RocksDB is not >>>>> recovering from local but from a remote filesystem. This recovery >>>>> basically >>>>> has steps: >>>>> >>>>> 1: Create a temporary directory (in your example, this is the dir that >>>>> ends …/5683a26f-cde2-406d-b4cf-3c6c3976f8ba) and download all the files, >>>>> mainly sst files from remote fs to the temporary directory in local fs. >>>>> >>>>> 2: List all the downloaded files in the temporary directory and either >>>>> hardlink (for sst files) or copy (for all other files) the listed files >>>>> into the new RocksDb instance path (the path that ends with …/db) >>>>> >>>>> 3: Open the new db from the instance path, delete the temporary >>>>> directory. >>>>> >>>>> Now what is very surprising here is that it claims some file was not >>>>> found (not clear which one, but I assume the downloaded file). However, >>>>> how >>>>> the file can be lost between downloading/listing and the attempt to >>>>> hardlink it is very mysterious. Can you check the logs for any other >>>>> exceptions and can you check what files exist in the recovery (e.g. what >>>>> is >>>>> downloaded, if the instance path is there, …). For now, I cannot see how a >>>>> listed file could suddenly disappear, Flink will only delete the temporary >>>>> directory if recovery is completed or failed. >>>>> >>>>> Also: is this problem deterministic or was this a singularity? Did you >>>>> use a different Flink version before (which worked)? >>>>> >>>>> Best, >>>>> Stefan >>>>> >>>>> On 7. Dec 2018, at 11:28, Ben Yan <yan.xiao.bin.m...@gmail.com> wrote: >>>>> >>>>> hi . I am using flink-1.7.0. I am using RockDB and hdfs as >>>>> statebackend, but recently I found the following exception when the job >>>>> resumed from the checkpoint. Task-local state is always considered a >>>>> secondary copy, the ground truth of the checkpoint state is the primary >>>>> copy in the distributed store. But it seems that the job did not >>>>> recover from hdfs, and it failed directly.Hope someone can give me >>>>> advices or hints about the problem that I encountered. >>>>> >>>>> >>>>> 2018-12-06 22:54:04,171 INFO >>>>> org.apache.flink.runtime.executiongraph.ExecutionGraph - >>>>> KeyedProcess (3/138) (5d96a585130f7a21f22f82f79941fb1d) switched from >>>>> RUNNING to FAILED. >>>>> java.lang.Exception: Exception while creating StreamOperatorStateContext. >>>>> at >>>>> org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.streamOperatorStateContext(StreamTaskStateInitializerImpl.java:195) >>>>> at >>>>> org.apache.flink.streaming.api.operators.AbstractStreamOperator.initializeState(AbstractStreamOperator.java:250) >>>>> at >>>>> org.apache.flink.streaming.runtime.tasks.StreamTask.initializeState(StreamTask.java:738) >>>>> at >>>>> org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:289) >>>>> at org.apache.flink.runtime.taskmanager.Task.run(Task.java:704) >>>>> at java.lang.Thread.run(Thread.java:748) >>>>> Caused by: org.apache.flink.util.FlinkException: Could not restore keyed >>>>> state backend for >>>>> KeyedProcessOperator_e528d5d97ea2d7cefbcf6ff5b46354d5_(3/138) from any of >>>>> the 1 provided restore options. >>>>> at >>>>> org.apache.flink.streaming.api.operators.BackendRestorerProcedure.createAndRestore(BackendRestorerProcedure.java:137) >>>>> at >>>>> org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.keyedStatedBackend(StreamTaskStateInitializerImpl.java:284) >>>>> at >>>>> org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.streamOperatorStateContext(StreamTaskStateInitializerImpl.java:135) >>>>> ... 5 more >>>>> Caused by: java.nio.file.NoSuchFileException: >>>>> /mnt/yarn/local/usercache/yarn/appcache/application_1544101169829_0004/flink-io-0115e9d6-a816-4b65-8944-1423f0fdae58/job_6e40c9381aa12f69b6ac182c91d993f5_op_KeyedProcessOperator_e528d5d97ea2d7cefbcf6ff5b46354d5__3_138__uuid_1c6a5a11-caaf-4564-b3d0-9c7dadddc390/db/000495.sst >>>>> -> >>>>> /mnt/yarn/local/usercache/yarn/appcache/application_1544101169829_0004/flink-io-0115e9d6-a816-4b65-8944-1423f0fdae58/job_6e40c9381aa12f69b6ac182c91d993f5_op_KeyedProcessOperator_e528d5d97ea2d7cefbcf6ff5b46354d5__3_138__uuid_1c6a5a11-caaf-4564-b3d0-9c7dadddc390/5683a26f-cde2-406d-b4cf-3c6c3976f8ba/000495.sst >>>>> at >>>>> sun.nio.fs.UnixException.translateToIOException(UnixException.java:86) >>>>> at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:102) >>>>> at >>>>> sun.nio.fs.UnixFileSystemProvider.createLink(UnixFileSystemProvider.java:476) >>>>> at java.nio.file.Files.createLink(Files.java:1086) >>>>> at >>>>> org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend$RocksDBIncrementalRestoreOperation.restoreInstanceDirectoryFromPath(RocksDBKeyedStateBackend.java:1238) >>>>> at >>>>> org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend$RocksDBIncrementalRestoreOperation.restoreLocalStateIntoFullInstance(RocksDBKeyedStateBackend.java:1186) >>>>> at >>>>> org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend$RocksDBIncrementalRestoreOperation.restoreWithoutRescaling(RocksDBKeyedStateBackend.java:916) >>>>> at >>>>> org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend$RocksDBIncrementalRestoreOperation.restore(RocksDBKeyedStateBackend.java:864) >>>>> at >>>>> org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend.restore(RocksDBKeyedStateBackend.java:525) >>>>> at >>>>> org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackend.restore(RocksDBKeyedStateBackend.java:147) >>>>> at >>>>> org.apache.flink.streaming.api.operators.BackendRestorerProcedure.attemptCreateAndRestore(BackendRestorerProcedure.java:151) >>>>> at >>>>> org.apache.flink.streaming.api.operators.BackendRestorerProcedure.createAndRestore(BackendRestorerProcedure.java:123) >>>>> ... 7 more >>>>> >>>>> >>>>> Best >>>>> >>>>> Ben >>>>> >>>>> >>>>> >>>> >>>
