由于 ClosedChannelException (DFSOutputStream.checkClosed)，Spark 作业失败

Question

我有一个 spark 应用程序。我使用 saveAsNewAPIHadoopDataset 在 hdfs 上存储一个 rdd，利用 AvroKeyOutputFormat.

对于大型 RDD，有时我会收到太多 ClosedChannelException 以致应用程序最终中止。

我在某处读到设置 hadoopConf.set("fs.hdfs.impl.disable.cache", "false"); 有帮助。

以下是我保存 rdd 的方法：

        hadoopConf.set("fs.hdfs.impl.disable.cache", "false");
        final Job job = Job.getInstance(hadoopConf);            
        FileOutputFormat.setOutputPath(job, outPutPath);
        AvroJob.setOutputKeySchema(job, MyClass.SCHEMA$);
        job.setOutputFormatClass(AvroKeyOutputFormat.class);

        rdd                    
                .mapToPair(new PreparePairForDatnum())
                .saveAsNewAPIHadoopDataset(job.getConfiguration());

这是堆栈跟踪：

java.nio.channels.ClosedChannelException
    at org.apache.hadoop.hdfs.DFSOutputStream.checkClosed(DFSOutputStream.java:1765)
    at org.apache.hadoop.fs.FSOutputSummer.write(FSOutputSummer.java:108)
    at org.apache.hadoop.fs.FSDataOutputStream$PositionCache.write(FSDataOutputStream.java:58)
    at java.io.DataOutputStream.write(DataOutputStream.java:107)
    at org.apache.avro.file.DataFileWriter$BufferedFileOutputStream$PositionFilter.write(DataFileWriter.java:458)
    at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82)
    at java.io.BufferedOutputStream.write(BufferedOutputStream.java:121)
    at org.apache.avro.io.BufferedBinaryEncoder$OutputStreamSink.innerWrite(BufferedBinaryEncoder.java:216)
    at org.apache.avro.io.BufferedBinaryEncoder.writeFixed(BufferedBinaryEncoder.java:150)
    at org.apache.avro.file.DataFileStream$DataBlock.writeBlockTo(DataFileStream.java:369)
    at org.apache.avro.file.DataFileWriter.writeBlock(DataFileWriter.java:395)
    at org.apache.avro.file.DataFileWriter.writeIfBlockFull(DataFileWriter.java:340)
    at org.apache.avro.file.DataFileWriter.append(DataFileWriter.java:311)
    at org.apache.avro.mapreduce.AvroKeyRecordWriter.write(AvroKeyRecordWriter.java:77)
    at org.apache.avro.mapreduce.AvroKeyRecordWriter.write(AvroKeyRecordWriter.java:39)
    at org.apache.spark.rdd.PairRDDFunctions$$anonfun$saveAsNewAPIHadoopDataset$$anonfun$$anonfun$apply.apply$mcV$sp(PairRDDFunctions.scala:1036)
    at org.apache.spark.rdd.PairRDDFunctions$$anonfun$saveAsNewAPIHadoopDataset$$anonfun$$anonfun$apply.apply(PairRDDFunctions.scala:1034)
    at org.apache.spark.rdd.PairRDDFunctions$$anonfun$saveAsNewAPIHadoopDataset$$anonfun$$anonfun$apply.apply(PairRDDFunctions.scala:1034)
    at org.apache.spark.util.Utils$.tryWithSafeFinally(Utils.scala:1206)
    at org.apache.spark.rdd.PairRDDFunctions$$anonfun$saveAsNewAPIHadoopDataset$$anonfun.apply(PairRDDFunctions.scala:1042)
    at org.apache.spark.rdd.PairRDDFunctions$$anonfun$saveAsNewAPIHadoopDataset$$anonfun.apply(PairRDDFunctions.scala:1014)
    at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:66)
    at org.apache.spark.scheduler.Task.run(Task.scala:88)
    at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:214)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
    Suppressed: java.nio.channels.ClosedChannelException
        at org.apache.hadoop.hdfs.DFSOutputStream.checkClosed(DFSOutputStream.java:1765)
        at org.apache.hadoop.fs.FSOutputSummer.write(FSOutputSummer.java:108)
        at org.apache.hadoop.fs.FSDataOutputStream$PositionCache.write(FSDataOutputStream.java:58)
        at java.io.DataOutputStream.write(DataOutputStream.java:107)
        at org.apache.avro.file.DataFileWriter$BufferedFileOutputStream$PositionFilter.write(DataFileWriter.java:458)
        at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82)
        at java.io.BufferedOutputStream.write(BufferedOutputStream.java:121)
        at org.apache.avro.io.BufferedBinaryEncoder$OutputStreamSink.innerWrite(BufferedBinaryEncoder.java:216)
        at org.apache.avro.io.BufferedBinaryEncoder.writeFixed(BufferedBinaryEncoder.java:150)
        at org.apache.avro.file.DataFileStream$DataBlock.writeBlockTo(DataFileStream.java:369)
        at org.apache.avro.file.DataFileWriter.writeBlock(DataFileWriter.java:395)
        at org.apache.avro.file.DataFileWriter.sync(DataFileWriter.java:413)
        at org.apache.avro.file.DataFileWriter.flush(DataFileWriter.java:422)
        at org.apache.avro.file.DataFileWriter.close(DataFileWriter.java:445)
        at org.apache.avro.mapreduce.AvroKeyRecordWriter.close(AvroKeyRecordWriter.java:83)
        at org.apache.spark.rdd.PairRDDFunctions$$anonfun$saveAsNewAPIHadoopDataset$$anonfun$$anonfun$apply.apply$mcV$sp(PairRDDFunctions.scala:1043)
        at org.apache.spark.util.Utils$.tryWithSafeFinally(Utils.scala:1215)
        ... 8 more

Answer 1

执行者被杀时可能发生。在您的日志中查看类似内容：

2016-07-20 22:00:42,976 | WARN  | org.apache.spark.scheduler.cluster.YarnSchedulerBackend$YarnSchedulerEndpoint | Container container_e10838_1468831508103_1724_01_055482 on host: hostName was preempted.
2016-07-20 22:00:42,977 | ERROR | org.apache.spark.scheduler.cluster.YarnClusterScheduler | Lost executor 6 on hostName: Container container_e10838_1468831508103_1724_01_055482 on host: hostName was preempted.

如果你找到了，那么你的任务的执行者被 yarn application master 抢占了。换句话说，他被杀了，又得到了一个运行队列。关于抢占和yarn调度可以参考here and here.

由于 ClosedChannelException (DFSOutputStream.checkClosed)，Spark 作业失败

Spark job-failure due to ClosedChannelException (DFSOutputStream.checkClosed)

java

hadoop

hdfs

avro

apache-spark