hadoop - 运行HBase MapReduce作业时出现NullPoinerEcxeption

Question

我试图在hadoop中运行HBase Mapreduce作业。
我使用${HADOOP_HOME}/bin/hadoop jar ${HBASE_HOME}/lib/hbase-server-VERSION.jar rowcounter usertable来运行作业。

运行时出现以下异常

Exception in thread "main" java.lang.reflect.InvocationTargetException
        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.hbase.mapreduce.Driver.main(Driver.java:54)
        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:212)
Caused by: java.lang.NullPointerException
        at org.apache.hadoop.net.DNS.reverseDns(DNS.java:92)
        at org.apache.hadoop.hbase.mapreduce.TableInputFormatBase.reverseDNS(TableInputFormatBase.java:228)
        at org.apache.hadoop.hbase.mapreduce.TableInputFormatBase.getSplits(TableInputFormatBase.java:191)
        at org.apache.hadoop.mapreduce.JobSubmitter.writeNewSplits(JobSubmitter.java:493)
        at org.apache.hadoop.mapreduce.JobSubmitter.writeSplits(JobSubmitter.java:510)
        at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:394)
        at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1285)
        at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1282)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:396)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1614)
        at org.apache.hadoop.mapreduce.Job.submit(Job.java:1282)
        at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:1303)
        at org.apache.hadoop.hbase.mapreduce.RowCounter.main(RowCounter.java:191)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.apache.hadoop.util.ProgramDriver$ProgramDescription.invoke(ProgramDriver.java:72)
        at org.apache.hadoop.util.ProgramDriver.run(ProgramDriver.java:145)
        at org.apache.hadoop.util.ProgramDriver.driver(ProgramDriver.java:153)
        ... 10 more

谁能解释为什么此NullPointerException引发

Answer 1

Caused by: java.lang.NullPointerException
        at org.apache.hadoop.net.DNS.reverseDns(DNS.java:92)
        at org.apache.hadoop.hbase.mapreduce.TableInputFormatBase.reverseDNS(TableInputFormatBase.java:228)
        at org.apache.hadoop.hbase.mapreduce.TableInputFormatBase.getSplits(TableInputFormatBase.java:191)

根据上述异常(exception)，在执行Reversedns查找时似乎存在一些问题。这表明存在infrstructure / network / os设置问题。