5.运行wordcount实例
(1)格式化HDFS
$bin/hadoop namenode -format
格式化执行信息如下所示:
10/08/01 19:04:02 INFO namenode.NameNode: STARTUP_MSG:
/************************************************************
STARTUP_MSG: Starting NameNode
STARTUP_MSG: host = localhost/127.0.0.1
STARTUP_MSG: args = [-format]
STARTUP_MSG: version = 0.19.0
STARTUP_MSG: build = https://svn.apache.org/repos/asf/hadoop/core/branches/branch-0.19 -r 713890; compiled by 'ndaley' on Fri Nov 14 03:12:29 UTC 2008
************************************************************/
Re-format filesystem in /tmp/hadoop-root/dfs/name ? (Y or N) y
Format aborted in /tmp/hadoop-root/dfs/name
10/08/01 19:04:05 INFO namenode.NameNode: SHUTDOWN_MSG:
/************************************************************
SHUTDOWN_MSG: Shutting down NameNode at localhost/127.0.0.1
************************************************************/
(2)启动Hadoop相关后台进程
$bin/start-all.sh
starting namenode, logging to /root/hadoop-0.19.0/bin/../logs/hadoop-root-namenode-localhost.out
localhost: starting datanode, logging to /root/hadoop-0.19.0/bin/../logs/hadoop-root-datanode-localhost.out
localhost: starting secondarynamenode, logging to /root/hadoop-0.19.0/bin/../logs/hadoop-root-secondarynamenode-localhost.out
starting jobtracker, logging to /root/hadoop-0.19.0/bin/../logs/hadoop-root-jobtracker-localhost.out
localhost: starting tasktracker, logging to /root/hadoop-0.19.0/bin/../logs/hadoop-root-tasktracker-localhost.out
1、Call to localhost/127.0.0.1:9000 failed on local exception异常
(1)异常描述
可能你会在执行如下命令行的时候出现:
[iyunv@localhost hadoop-0.19.0]# bin/hadoop jar hadoop-0.19.0-examples.jar wordcount input output
出错异常信息如下所示:
10/08/01 19:50:55 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 0 time(s).
10/08/01 19:50:56 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 1 time(s).
10/08/01 19:50:57 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 2 time(s).
10/08/01 19:50:58 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 3 time(s).
10/08/01 19:50:59 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 4 time(s).
10/08/01 19:51:00 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 5 time(s).
10/08/01 19:51:01 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 6 time(s).
10/08/01 19:51:02 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 7 time(s).
10/08/01 19:51:03 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 8 time(s).
10/08/01 19:51:04 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 9 time(s).
java.lang.RuntimeException: java.io.IOException: Call to localhost/127.0.0.1:9000 failed on local exception: Connection refused
at org.apache.hadoop.mapred.JobConf.getWorkingDirectory(JobConf.java:323)
at org.apache.hadoop.mapred.FileInputFormat.setInputPaths(FileInputFormat.java:295)
at org.apache.hadoop.mapred.FileInputFormat.setInputPaths(FileInputFormat.java:268)
at org.apache.hadoop.examples.WordCount.run(WordCount.java:146)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
at org.apache.hadoop.examples.WordCount.main(WordCount.java:155)
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.util.ProgramDriver$ProgramDescription.invoke(ProgramDriver.java:68)
at org.apache.hadoop.util.ProgramDriver.driver(ProgramDriver.java:141)
at org.apache.hadoop.examples.ExampleDriver.main(ExampleDriver.java:61)
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.util.RunJar.main(RunJar.java:165)
at org.apache.hadoop.mapred.JobShell.run(JobShell.java:54)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:79)
at org.apache.hadoop.mapred.JobShell.main(JobShell.java:68)
Caused by: java.io.IOException: Call to localhost/127.0.0.1:9000 failed on local exception: Connection refused
at org.apache.hadoop.ipc.Client.call(Client.java:699)
at org.apache.hadoop.ipc.RPC$Invoker.invoke(RPC.java:216)
at $Proxy0.getProtocolVersion(Unknown Source)
at org.apache.hadoop.ipc.RPC.getProxy(RPC.java:319)
at org.apache.hadoop.hdfs.DFSClient.createRPCNamenode(DFSClient.java:104)
at org.apache.hadoop.hdfs.DFSClient.<init>(DFSClient.java:177)
at org.apache.hadoop.hdfs.DistributedFileSystem.initialize(DistributedFileSystem.java:74)
at org.apache.hadoop.fs.FileSystem.createFileSystem(FileSystem.java:1367)
at org.apache.hadoop.fs.FileSystem.access$200(FileSystem.java:56)
at org.apache.hadoop.fs.FileSystem$Cache.get(FileSystem.java:1379)
at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:215)
at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:120)
at org.apache.hadoop.mapred.JobConf.getWorkingDirectory(JobConf.java:319)
... 21 more
Caused by: java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:574)
at sun.nio.ch.SocketAdaptor.connect(SocketAdaptor.java:100)
at org.apache.hadoop.ipc.Client$Connection.setupIOstreams(Client.java:299)
at org.apache.hadoop.ipc.Client$Connection.access$1700(Client.java:176)
at org.apache.hadoop.ipc.Client.getConnection(Client.java:772)
at org.apache.hadoop.ipc.Client.call(Client.java:685)
... 33 more
(2)异常分析
从上述异常信息分析,这句是关键:
Retrying connect to server: localhost/127.0.0.1:9000.
[iyunv@localhost hadoop-0.19.0]# bin/hadoop jar hadoop-0.19.0-examples.jar wordcount input output
结果抛出一堆异常,信息如下:
org.apache.hadoop.mapred.InvalidInputException: Input path does not exist: hdfs://localhost:9000/user/root/input
at org.apache.hadoop.mapred.FileInputFormat.listStatus(FileInputFormat.java:179)
at org.apache.hadoop.mapred.FileInputFormat.getSplits(FileInputFormat.java:190)
at org.apache.hadoop.mapred.JobClient.submitJob(JobClient.java:782)
at org.apache.hadoop.mapred.JobClient.runJob(JobClient.java:1127)
at org.apache.hadoop.examples.WordCount.run(WordCount.java:149)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
at org.apache.hadoop.examples.WordCount.main(WordCount.java:155)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.util.ProgramDriver$ProgramDescription.invoke(ProgramDriver.java:68)
at org.apache.hadoop.util.ProgramDriver.driver(ProgramDriver.java:141)
at org.apache.hadoop.examples.ExampleDriver.main(ExampleDriver.java:61)
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.util.RunJar.main(RunJar.java:165)
at org.apache.hadoop.mapred.JobShell.run(JobShell.java:54)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:79)
at org.apache.hadoop.mapred.JobShell.main(JobShell.java:68)