java – Amazon EMR：使用S3的输入和输出运行Custom Jar

我正在尝试运行具有自定义jar步骤的EMR集群.程序从S3获取输入并输出到S3(或者至少这是我想要完成的).在步骤配置中,我在arguments字段中有以下内容：

v3.MaxTemperatureDriver
s3n://hadoopbook/ncdc/all
s3n://hadoop-szhu/max-temp

其中hadoopbook / ncdc / all是包含输入数据的存储桶的路径(作为旁注,我正在运行的示例来自此book),而hadoop-szhu是我自己的存储桶,我想存储输出.在此post之后,我的MapReduce驱动程序如下所示：

package v3;

import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;

import v1.MaxTemperatureReducer;

public class MaxTemperatureDriver extends Configured implements Tool {

  @Override
  public int run(String[] args) throws Exception {
    if (args.length != 2) {
      System.err.printf("Usage: %s [generic options] <input> <output>\n",getClass().getSimpleName());
      ToolRunner.printGenericCommandUsage(System.err);
      return -1;
    }

    Job job = new Job(getConf(),"Max temperature");
    job.setJarByClass(getClass());

    FileInputFormat.addInputPath(job,new Path(args[0]));
    FileOutputFormat.setoutputPath(job,new Path(args[1]));

    job.setMapperClass(MaxTemperatureMapper.class);
    job.setCombinerClass(MaxTemperatureReducer.class);
    job.setReducerClass(MaxTemperatureReducer.class);

    job.setoutputKeyClass(Text.class);
    job.setoutputValueClass(IntWritable.class);

    return job.waitForCompletion(true) ? 0 : 1;
  }

  public static void main(String[] args) throws Exception {
    int exitCode = ToolRunner.run(new MaxTemperatureDriver(),args);
    System.exit(exitCode);
  }
}

但是,当我尝试运行它时,我收到以下错误：

Exception in thread "main" java.io.IOException: No FileSystem for scheme: s3n

我还尝试使用以下方法将数据从s3复制到集群(在sshing进入主节点后运行)：

hadoop distcp \
  -Dfs.s3n.awsAccessKeyId='...' \
  -Dfs.s3n.awsSecretAccessKey='...' \
  s3n://hadoopbook/ncdc/all input/ncdc/all

但是我收到了一些错误,我在下面列出了一段摘录：

2016-09-03 07:07:11,858 FATAL [IPC Server handler 6 on 43495] org.apache.hadoop.mapred.TaskAttemptListenerImpl: Task: attempt_1472884232220_0001_m_000000_0 - exited : java.io.IOException: org.apache.hadoop.tools.mapred.RetriableFileCopycommand$copyReadException: java.io.FileNotFoundException: No such file or directory 's3n://hadoopbook/ncdc/all/1901.gz'
    at org.apache.hadoop.tools.mapred.copyMapper.map(copyMapper.java:224)
    at org.apache.hadoop.tools.mapred.copyMapper.map(copyMapper.java:50)
    at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:146)
    at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:796)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:342)
    at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:164)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:422)
    at org.apache.hadoop.security.UserGroupinformation.doAs(UserGroupinformation.java:1657)
    at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:158)
Caused by: org.apache.hadoop.tools.mapred.RetriableFileCopycommand$copyReadException: java.io.FileNotFoundException: No such file or directory 's3n://hadoopbook/ncdc/all/1901.gz'
    ... 10 more
Caused by: java.io.FileNotFoundException: No such file or directory 's3n://hadoopbook/ncdc/all/1901.gz'
    at com.amazon.ws.emr.hadoop.fs.s3n.S3NativeFileSystem.getFileStatus(S3NativeFileSystem.java:818)
    at com.amazon.ws.emr.hadoop.fs.EmrFileSystem.getFileStatus(EmrFileSystem.java:511)
    at org.apache.hadoop.tools.mapred.copyMapper.map(copyMapper.java:219)
    ... 9 more

我不确定问题出在哪里,但我很乐意提供更多细节(请在下面评论).谢谢！

解决方法

s3n：//是旧协议,你应该使用s3：//

参考：http://docs.aws.amazon.com//ElasticMapReduce/latest/ManagementGuide/emr-plan-file-systems.html