[jira] [Created] (FLINK-12379) Parallelism in job/GCS/Hadoop: Could not finalize the pending checkpoint

[Shang Yuanchun (Jira)]

Henrik created FLINK-12379:
------------------------------

             Summary: Parallelism in job/GCS/Hadoop: Could not finalize the pending checkpoint
                 Key: FLINK-12379
                 URL: https://issues.apache.org/jira/browse/FLINK-12379
             Project: Flink
          Issue Type: Bug
          Components: FileSystems
    Affects Versions: 1.8.0
         Environment: GCS +

 
{code:java}
<flink.version>1.8.0</flink.version>
<java.version>1.8</java.version>
<scala.binary.version>2.11</scala.binary.version>{code}
{code:java}
<!-- Cloud Storage: -->
<!-- https://search.maven.org/search?q=g:com.google.cloud.bigdataoss -->
<!-- https://github.com/GoogleCloudPlatform/bigdata-interop/blob/master/pubsub/README.md -->
<dependency>
  <groupId>com.google.cloud.bigdataoss</groupId>
  <artifactId>gcs-connector</artifactId>
  <version>hadoop2-1.9.16</version>
</dependency>
<dependency>
  <groupId>org.apache.flink</groupId>
  <artifactId>flink-connector-filesystem_2.11</artifactId>
  <version>${flink.version}</version>
</dependency>
<dependency>
  <groupId>org.apache.flink</groupId>
  <artifactId>flink-hadoop-fs</artifactId>
  <version>${flink.version}</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.flink/flink-shaded-hadoop2 -->
<dependency>
  <groupId>org.apache.flink</groupId>
  <artifactId>flink-shaded-hadoop2</artifactId>
  <version>${hadoop.version}-${flink.version}</version>
</dependency>
{code}
 

 
            Reporter: Henrik


When running a standalone-job w/ parallelism=4 + taskmanager, you will shortly get this crash
{code:java}
2019-04-30 22:20:02,928 WARN  org.apache.flink.runtime.jobmaster.JobMaster                  - Error while processing checkpoint acknowledgement message
org.apache.flink.runtime.checkpoint.CheckpointException: Could not finalize the pending checkpoint 5.
    at org.apache.flink.runtime.checkpoint.CheckpointCoordinator.completePendingCheckpoint(CheckpointCoordinator.java:837)
    at org.apache.flink.runtime.checkpoint.CheckpointCoordinator.receiveAcknowledgeMessage(CheckpointCoordinator.java:756)
    at org.apache.flink.runtime.jobmaster.JobMaster.lambda$acknowledgeCheckpoint$9(JobMaster.java:676)
    at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:39)
    at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:415)
    at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
    at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
    at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
    at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
Caused by: org.apache.hadoop.fs.FileAlreadyExistsException: 'gs://example_bucket/flink/checkpoints/00000000000000000000000000000000/chk-5/_metadata' already exists
    at com.google.cloud.hadoop.fs.gcs.GoogleHadoopOutputStream.createChannel(GoogleHadoopOutputStream.java:85)
    at com.google.cloud.hadoop.fs.gcs.GoogleHadoopOutputStream.<init>(GoogleHadoopOutputStream.java:74)
    at com.google.cloud.hadoop.fs.gcs.GoogleHadoopFileSystemBase.create(GoogleHadoopFileSystemBase.java:797)
    at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:929)
    at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:910)
    at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:807)
    at org.apache.flink.runtime.fs.hdfs.HadoopFileSystem.create(HadoopFileSystem.java:141)
    at org.apache.flink.runtime.fs.hdfs.HadoopFileSystem.create(HadoopFileSystem.java:37)
    at org.apache.flink.runtime.state.filesystem.FsCheckpointMetadataOutputStream.<init>(FsCheckpointMetadataOutputStream.java:65)
    at org.apache.flink.runtime.state.filesystem.FsCheckpointStorageLocation.createMetadataOutputStream(FsCheckpointStorageLocation.java:104)
    at org.apache.flink.runtime.checkpoint.PendingCheckpoint.finalizeCheckpoint(PendingCheckpoint.java:259)
    at org.apache.flink.runtime.checkpoint.CheckpointCoordinator.completePendingCheckpoint(CheckpointCoordinator.java:829)
    ... 8 more
Caused by: java.nio.file.FileAlreadyExistsException: Object gs://example_bucket/flink/checkpoints/00000000000000000000000000000000/chk-5/_metadata already exists.
    at com.google.cloud.hadoop.gcsio.GoogleCloudStorageImpl.getWriteGeneration(GoogleCloudStorageImpl.java:1918)
    at com.google.cloud.hadoop.gcsio.GoogleCloudStorageImpl.create(GoogleCloudStorageImpl.java:410)
    at com.google.cloud.hadoop.gcsio.GoogleCloudStorageFileSystem.createInternal(GoogleCloudStorageFileSystem.java:286)
    at com.google.cloud.hadoop.gcsio.GoogleCloudStorageFileSystem.create(GoogleCloudStorageFileSystem.java:264)
    at com.google.cloud.hadoop.fs.gcs.GoogleHadoopOutputStream.createChannel(GoogleHadoopOutputStream.java:82)
    ... 19 more
2019-04-30 22:20:03,114 INFO  org.apache.flink.runtime.checkpoint.CheckpointCoordinator     - Triggering checkpoint 6 @ 1556662802928 for job 00000000000000000000000000000000.{code}
My guess at why; concurrent checkpoint writers are updating the _metadata resource concurrently. They should be using optimistic concurrency control with ETag on GCS, and then retry until successful.



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