1

编辑：

查看 namenode 日志，我注意到定期引发异常。它可能是相关的吗？

2013-04-10 19:23:50,613 WARN org.apache.hadoop.security.ShellBasedUnixGroupsMapping (IPC Server handler 43 on 9000): got exception trying to get groups for user job_201304101854_0005
org.apache.hadoop.util.Shell$ExitCodeException: id: job_201304101854_0005: No such user

    at org.apache.hadoop.util.Shell.runCommand(Shell.java:255)
    at org.apache.hadoop.util.Shell.run(Shell.java:182)
    at org.apache.hadoop.util.Shell$ShellCommandExecutor.execute(Shell.java:375)
    at org.apache.hadoop.util.Shell.execCommand(Shell.java:461)
    at org.apache.hadoop.util.Shell.execCommand(Shell.java:444)
    at org.apache.hadoop.security.ShellBasedUnixGroupsMapping.getUnixGroups(ShellBasedUnixGroupsMapping.java:78)
    at org.apache.hadoop.security.ShellBasedUnixGroupsMapping.getGroups(ShellBasedUnixGroupsMapping.java:53)
    at org.apache.hadoop.security.Groups.getGroups(Groups.java:79)
    at org.apache.hadoop.security.UserGroupInformation.getGroupNames(UserGroupInformation.java:1037)
    at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.<init>(FSPermissionChecker.java:50)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkPermission(FSNamesystem.java:5218)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkTraverse(FSNamesystem.java:5201)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getFileInfo(FSNamesystem.java:2030)
    at org.apache.hadoop.hdfs.server.namenode.NameNode.getFileInfo(NameNode.java:850)
    at sun.reflect.GeneratedMethodAccessor3.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:573)
    at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1393)
    at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1389)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:396)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1132)
    at org.apache.hadoop.ipc.Server$Handler.run(Server.java:1387)
2013-04-10 19:23:50,614 INFO org.apache.hadoop.security.ShellBasedUnixGroupsMapping (IPC Server handler 43 on 9000): add job_201304101854_0005 to shell userGroupsCache
2013-04-10 19:23:50,614 WARN org.apache.hadoop.security.UserGroupInformation (IPC Server handler 43 on 9000): No groups available for user job_201304101854_0005
2013-04-10 19:23:55,886 WARN org.apache.hadoop.security.UserGroupInformation (IPC Server handler 46 on 9000): No groups available for user job_201304101854_0005

我们制作了自定义二进制文件来执行 map 和 reduce，使用常识“cat 文件 | map | sort | reduce > output”模式测试了它们的正确操作。我们确保静态编译二进制文件以引入尽可能多的依赖项，并且我们还通过手动将二进制文件上传到主服务器来确认二进制文件在 Amazon 的 EMR AMI 上运行。如果相关，我们选择的语言是 Haskell，编译结果是一个简单的、本机的、二进制可执行文件。

以最简单的情况为例：

bin/hadoop jar contrib/streaming/hadoop-streaming.jar \
    -input s3n://path/to/input \
    -output s3n://path/to/output \
    -mapper "s3n://path/to/Program map" \
    -reducer "s3n://path/to/Program reduce"

这项工作确实开始了，但它卡在地图 0% 阶段并且没有让步。它不会从那里继续前进，并且没有任何日志似乎表明任何有用的东西。由于在 600 秒内“未报告”，每个地图任务都会被杀死。每个映射器都显示如下状态作为其状态，同时显示 0% 完成：

s3n://path/to/file.csv.gz:0+38175575

计数器部分显示了从 s3n 读取的类似 17.5KB 的内容。

如果我们现在将作业修改为以下内容以进行测试：

bin/hadoop jar contrib/streaming/hadoop-streaming.jar \
    -input s3n://path/to/input \
    -output s3n://path/to/output \
    -mapper s3n://elasticmapreduce/samples/wordcount/wordSplitter.py \
    -reducer aggregate

然后映射器阶段完成 100%，但减速器引发异常：

java.io.IOException: exception in uploadSinglePart
    at org.apache.hadoop.fs.s3native.MultipartUploadOutputStream.uploadSinglePart(MultipartUploadOutputStream.java:163)
    at org.apache.hadoop.fs.s3native.MultipartUploadOutputStream.close(MultipartUploadOutputStream.java:219)
    at org.apache.hadoop.fs.FSDataOutputStream$PositionCache.close(FSDataOutputStream.java:70)
    at org.apache.hadoop.fs.FSDataOutputStream.close(FSDataOutputStream.java:96)
    at org.apache.hadoop.mapred.TextOutputFormat$LineRecordWriter.close(TextOutputFormat.java:109)
    at org.apache.hadoop.mapred.ReduceTask$OldTrackingRecordWriter.close(ReduceTask.java:475)
    at org.apache.hadoop.mapred.ReduceTask.runOldReducer(ReduceTask.java:539)
    at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:429)
    at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:396)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1132)
    at org.apache.hadoop.mapred.Child.main(Child.java:249)
Caused by: java.lang.RuntimeException: exception in putObject
    at org.apache.hadoop.fs.s3native.Jets3tNativeFileSystemStore.storeFile(Jets3tNativeFileSystemStore.java:128)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:83)
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:59)
    at org.apache.hadoop.fs.s3native.$Proxy3.storeFile(Unknown Source)
    at org.apache.hadoop.fs.s3native.MultipartUploadOutputStream.uploadSinglePart(MultipartUploadOutputStream.java:160)
    ... 12 more
Caused by: Status Code: 403, AWS Service: Amazon S3, AWS Request ID: 8220819721FFE29E, AWS Error Code: AccessDenied, AWS Error Message: Access Denied, S3 Extended Request ID: TekkBZzgaBlK0e8SkoC7bcBsu1w7Nbpy2U7hPCGp5IPrrsqaPTxUg7QQ09xTXRYC
    at com.amazonaws.http.AmazonHttpClient.handleErrorResponse(AmazonHttpClient.java:619)
    at com.amazonaws.http.AmazonHttpClient.executeHelper(AmazonHttpClient.java:317)
    at com.amazonaws.http.AmazonHttpClient.execute(AmazonHttpClient.java:170)
    at com.amazonaws.services.s3.AmazonS3Client.invoke(AmazonS3Client.java:2943)
    at com.amazonaws.services.s3.AmazonS3Client.putObject(AmazonS3Client.java:1123)
    at org.apache.hadoop.fs.s3native.Jets3tNativeFileSystemStore.storeFile(Jets3tNativeFileSystemStore.java:121)
    ... 20 more

令人沮丧的是，例如，在相同类型的 EMR 集群上运行 hive 似乎在 S3 上创建新的外部映射表和文件时没有任何问题。

尝试了几个想法后，如果有人能给我们正确的方向以使我们的设置正常工作，我将不胜感激。

谢谢你，OA

4

1 回答 1

3

我认为这很可能是您的问题：

-mapper "s3n://path/to/Program map"

空格很可能会给您带来问题。我可能会尝试构建两个单独的二进制文件，一个用于 map，一个用于 reduce，您可以直接调用它们而不是传递参数。至少这将帮助您查明问题。

否则，这听起来像是 S3 许可或 mime 类型问题。我会检查您的存储桶的权限，以验证您用于 EMR 作业的凭据是否可以访问该存储桶。

一旦你确定在那里，我会检查二进制文件本身的权限和属性；当 S3 mime 类型设置不正确时，我遇到了奇怪的问题。例如，这里是 wordSplitter 信息：

$ s3cmd info s3://elasticmapreduce/samples/wordcount/wordSplitter.py
s3://elasticmapreduce/samples/wordcount/wordSplitter.py (object):
File size: 294
Last mod:  Wed, 29 Feb 2012 01:50:25 GMT
MIME type: text/x-python
MD5 sum:   f5b4829658cfbcd5fa5eb32c58163fa8

您的二进制文件可能默认为某种阻碍执行的 mime 类型。

于 2013-04-10T18:55:18.303 回答