我已经在两台机器上配置了hadoop。我可以使用ssh访问两台机器而不需要密码。我已经使用以下命令成功格式化了namenode:——
bin/hadoop namenode -format
然后我试着运行hadoop.tar附带的PI示例
sandip@master:~/hadoop-1.0.4$ bin/hadoop jar hadoop-examples-1.0.4.jar pi 5 500
Number of Maps = 5
Samples per Map = 500
13/04/14 04:13:04 INFO ipc.Client: Retrying connect to server:
master/192.168.188.131:9000. Already tried 0 time(s).
13/04/14 04:13:05 INFO ipc.Client: Retrying connect to server:
master/192.168.188.131:9000. Already tried 1 time(s).
13/04/14 04:13:06 INFO ipc.Client: Retrying connect to server:
master/192.168.188.131:9000. Already tried 2 time(s).
13/04/14 04:13:07 INFO ipc.Client: Retrying connect to server:
master/192.168.188.131:9000. Already tried 3 time(s).
13/04/14 04:13:08 INFO ipc.Client: Retrying connect to server:
master/192.168.188.131:9000. Already tried 4 time(s).
13/04/14 04:13:09 INFO ipc.Client: Retrying connect to server:
master/192.168.188.131:9000. Already tried 5 time(s).
13/04/14 04:13:10 INFO ipc.Client: Retrying connect to server:
master/192.168.188.131:9000. Already tried 6 time(s).
13/04/14 04:13:11 INFO ipc.Client: Retrying connect to server:
master/192.168.188.131:9000. Already tried 7 time(s).
13/04/14 04:13:12 INFO ipc.Client: Retrying connect to server:
master/192.168.188.131:9000. Already tried 8 time(s).
13/04/14 04:13:13 INFO ipc.Client: Retrying connect to server:
master/192.168.188.131:9000. Already tried 9 time(s).
java.lang.RuntimeException: java.net.ConnectException: Call to
master/192.168.188.131:9000 failed on connection exception: java.net.ConnectException:
Connection refused
at org.apache.hadoop.mapred.JobConf.getWorkingDirectory(JobConf.java:546)
at org.apache.hadoop.mapred.FileInputFormat.setInputPaths(FileInputFormat.java:318)
at org.apache.hadoop.examples.PiEstimator.estimate(PiEstimator.java:265)
at org.apache.hadoop.examples.PiEstimator.run(PiEstimator.java:342)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
at org.apache.hadoop.examples.PiEstimator.main(PiEstimator.java:351)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:616)
at
org.apache.hadoop.util.ProgramDriver$ProgramDescription.invoke(ProgramDriver.java:68)
at org.apache.hadoop.util.ProgramDriver.driver(ProgramDriver.java:139)
at org.apache.hadoop.examples.ExampleDriver.main(ExampleDriver.java:64)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at
哎呀，我忘了启动hadoop集群了。我通过运行这个命令修复了它:-
bin/start-all.sh
提示:连接被拒绝。通过查看日志，我可以说在启动集群时，您的机器无法连接到namenode。
检查以下事项:-名称节点地址是正确的(您使用core-site.xml中的default.fs.name给出它)-检查是否在mapred-site.xml中指定了正确的任务跟踪器地址—检查core-site.xml中是否指定了hadoop.tmp.dir属性。并且此目录在格式化后存在于您的机器上。
-格式化后，只需验证一件事是版本文件应该包含相同的名称空间id在主节点和从节点。