Question

我正在尝试使用EMR的Amazon s3存储。但是，当我目前运行我的代码时，我会遇到多个错误，如

java.lang.IllegalArgumentException: This file system object (hdfs://10.254.37.109:9000)    does not support access to the request path 's3n://energydata/input/centers_200_10k_norm.csv' You possibly called FileSystem.get(conf) when you should have called FileSystem.get(uri, conf) to obtain a file system supporting your path.
at org.apache.hadoop.fs.FileSystem.checkPath(FileSystem.java:384)
at org.apache.hadoop.hdfs.DistributedFileSystem.getPathName(DistributedFileSystem.java:129)
at org.apache.hadoop.hdfs.DistributedFileSystem.open(DistributedFileSystem.java:154)
at org.apache.hadoop.fs.FileSystem.open(FileSystem.java:429)
at edu.stanford.cs246.hw2.KMeans$CentroidMapper.setup(KMeans.java:112)
at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:142)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:771)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:375)
at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1132)
at org.apache.hadoop.mapred.Child.main(Child.java:249)

在main中我设置了这样的输入和输出路径，并将s3n：//energydata/input/centers_200_10k_norm.csv放在我在mapper和reducer中检索的配置CFILE中：

FileSystem fs = FileSystem.get(conf);
conf.set(CFILE, inPath); //inPath in this case is s3n://energydata/input/centers_200_10k_norm.csv
FileInputFormat.addInputPath(job, new Path(inputDir));
FileOutputFormat.setOutputPath(job, new Path(outputDir));

我的mapper和reducer中出现上述错误的具体示例，我尝试访问CFILE（s3n：//energydata/input/centers_200_10k_norm.csv）。这就是我尝试获取路径的方式：

FileSystem fs = FileSystem.get(context.getConfiguration());
Path cFile = new Path(context.getConfiguration().get(CFILE));
DataInputStream d = new DataInputStream(fs.open(cFile));  ---->Error

s3n：//energydata/input/centers_200_10k_norm.csv是程序的输入参数之一，当我启动EMR作业时，我将输入和输出目录指定为s3n：// energydata / input和s3n：/ / energydata /输出

我尝试了file path in hdfs中的建议，但我仍然收到错误。任何帮助将不胜感激。

谢谢！

Answer 1

尝试改为：

Path cFile = new Path(context.getConfiguration().get(CFILE));
FileSystem fs = cFile.getFileSystem(context.getConfiguration());
DataInputStream d = new DataInputStream(fs.open(cFile));

Answer 2

感谢。我实际上使用以下代码修复它：

String uriStr =  "s3n://energydata/centroid/";
URI uri = URI.create(uriStr);
FileSystem fs = FileSystem.get(uri, context.getConfiguration());    
Path cFile = new Path(context.getConfiguration().get(CFILE));  
DataInputStream d = new DataInputStream(fs.open(cFile));

使用amazon s3作为输入，输出并将中间结果存储在EMR map中减少作业

2 个答案: