Hi, I'm running a scala flink app in an AWS EMR cluster (emr 5.17, hadoop 2.8.4) with flink parallelization set to 400. The source is a Kafka topic and sinks to S3 in the format of: s3://<day>/<hour>/<worker_number>/<files>. There's potentially 400 files writing simultaneously.
Configuration: - Flink v1.5.2 - Checkpointing enabled w/ RocksDb (flink-statebackend-rocksdb_2.11, v1.6.1). Interval is every 2 mins with max concurrent set to 1. Min pause between checkpoints in 2 mins. Timeout is set to 2 mins. - BucketingSink (flink-connector-filesystem_2.11, v1.6.1). - Batch file size is set to 5mb. - Batch rollover interval is set to 30min - Writer uses GZip compression - Hadoop Maven Dependencies (hadoop-hdfs v3.1.1, hadoop-common v3.1.1, hadoop-core v1.2.1, hadoop-aws v3.1.1) The app is able to run for hours straight, but occasionally (once or twice a day), it displays the following exception. When this happens, the app is able to recover from previous checkpoint, but I am concerned about the exception: Caused by: java.io.IOException: com.amazon.ws.emr.hadoop.fs.shaded.com.amazonaws.services.s3.model.AmazonS3Exception: Not Found (Service: Amazon S3; Status Code 404; Error ... Request ID: xxxxxxxx, S3 Extended Request ID: xxxxxxxxxxxxxxxxxxxxxxxxxx - at com.amazon.ws.emr.hadoop.fs.s3n.Jets3tNativeFileSystemStore.handleAmazonServiceException(Jets3tNativeFileSystemStore.java:446) - at com.amazon.ws.emr.hadoop.fs.s3n.Jets3tNativeFileSystemStore.copy(Jets3tNativeFileSystemStore.java:427) - at com.amazon.ws.emr.hadoop.fs.s3n.S3NativeFileSystem.rename(S3NativeFileSystem.java:1297) - at com.amazon.ws.emr.hadoop.fs.EmrFileSystem.rename(EmrFileSystem.java:312) - at org.apache.flink.streaming.connectors.fs.bucketing.BucketingSink.handlePendingInProgressFile(BucketingSink.java:815) Caused by: com.amazon.ws.emr.hadoop.fs.shaded.com.amazonaws.services.s3.model.AmazonS3Exception: Not Found (Service: Amazon S3; Status Code 404; Error ... Request ID: xxxxxxxx, S3 Extended Request ID: xxxxxxxxxxxxxxxxxxxxxxxxxx - at com.amazon.ws.emr.hadoop.fs.shaded.com.amazonaws.http.AmazonHttpClient$RequestExecutor.handleErrorResponse(AmazonHttpClient.java:1632) - at com.amazon.ws.emr.hadoop.fs.shaded.com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeOneRequest(AmazonHttpClient.java:1304) - at com.amazon.ws.emr.hadoop.fs.shaded.com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeHelper(AmazonHttpClient.java:1058) - at com.amazon.ws.emr.hadoop.fs.shaded.com.amazonaws.http.AmazonHttpClient$RequestExecutor.doExecute(AmazonHttpClient.java:743) - at com.amazon.ws.emr.hadoop.fs.shaded.com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeWithTimer(AmazonHttpClient.java:717) - at com.amazon.ws.emr.hadoop.fs.shaded.com.amazonaws.http.AmazonHttpClient$RequestExecutor.execute(AmazonHttpClient.java:699) - at com.amazon.ws.emr.hadoop.fs.shaded.com.amazonaws.http.AmazonHttpClient$RequestExecutor.access$500(AmazonHttpClient.java:667) - at com.amazon.ws.emr.hadoop.fs.shaded.com.amazonaws.http.AmazonHttpClient$RequestExecutionBuilderImpl.execute(AmazonHttpClient.java:649) - at com.amazon.ws.emr.hadoop.fs.shaded.com.amazonaws.http.AmazonHttpClient.execute(AmazonHttpClient.java:513) - at com.amazon.ws.emr.hadoop.fs.shaded.com.amazonaws.services.s3.AmazonS3Client.invoke(AmazonS3Client.java:4365) - at com.amazon.ws.emr.hadoop.fs.shaded.com.amazonaws.services.s3.AmazonS3Client.invoke(AmazonS3Client.java:4312) - at com.amazon.ws.emr.hadoop.fs.shaded.com.amazonaws.services.s3.AmazonS3Client.getObjectMetadata(AmazonS3Client.java:1270) - at com.amazon.ws.emr.hadoop.fs.s3.lite.call.GetObjectMetadataCall.perform(GetObjectMetadataCall.java:22) - at com.amazon.ws.emr.hadoop.fs.s3.lite.call.GetObjectMetadataCall.perform(GetObjectMetadataCall.java:8) - at com.amazon.ws.emr.hadoop.fs.s3.lite.executor.GlobalS3Exxecutor.execute(GlobalS3Executor.java:91) And sometimes, it will show this: - java.lang.RuntimeException: Error while restoring BucketingSink state. - at org.apache.flink.streaming.connectors.fs.bucketing.BucketingSink.handlePendingInProgressFile(BucketingSink.java:888) - at org.apache.flink.streaming.connectors.fs.bucketing.BucketingSink.handleRestoredBucketState(BucketingSink.java:767) - at org.apache.flink.streaming.connectors.fs.bucketing.BucketingSink.initializeState(BucketingSink.java:394) - at org.apache.flink.streaming.util.functions.StreamingFunctionUtils.tryRestoreFunction(StreamingFunctionUtils.java:178) - at org.apache.flink.streaming.util.functions.StreamingFunctionUtils.restoreFunctionState(StreamingFunctionUtils.java:160) - at org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator.initializeState(AbstractUdfStreamOperator.java:96) - at org.apache.flink.streaming.api.operators.AbstractStreamOperator.initializeState(AbstractStreamOperator.java:254) - at org.apache.flink.streaming.runtime.tasks.StreamTask.initializeState(StreamTask.java:730) - at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:295) - at org.apache.flink.runtime.taskmanager.Task.run(Task.java:703) What causes this and how can it be resolved? Thank you. There seems to be a related Flink ticket and PR here, but I'm not sure if this is the exact same issue and if it has been resolved: https://issues.apache.org/jira/browse/FLINK-6306 https://github.com/apache/flink/pull/3752 https://github.com/apache/flink/pull/4607
