我是Hadoop的新手，最近我在Ubuntu 18.04上配置了Hadoop 3.1.2。我能够成功运行服务，但是，当我运行mapreduce的Pi示例时，得到以下信息：
ERROR [main] org.apache.hadoop.mapreduce.v2.app.MRAppMaster: Error starting MRAppMaster
org.apache.hadoop.yarn.exceptions.YarnRuntimeException: java.lang.NullPointerException
at org.apache.hadoop.mapreduce.v2.app.rm.RMCommunicator.register(RMCommunicator.java:178)
at org.apache.hadoop.mapreduce.v2.app.rm.RMCommunicator.serviceStart(RMCommunicator.java:122)
at org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator.serviceStart(RMContainerAllocator.java:280)
at org.apache.hadoop.service.AbstractService.start(AbstractService.java:194)
at org.apache.hadoop.mapreduce.v2.app.MRAppMaster$ContainerAllocatorRouter.serviceStart(MRAppMaster.java:979)
at org.apache.hadoop.service.AbstractService.start(AbstractService.java:194)
at org.apache.hadoop.service.CompositeService.serviceStart(CompositeService.java:121)
at org.apache.hadoop.mapreduce.v2.app.MRAppMaster.serviceStart(MRAppMaster.java:1293)
at org.apache.hadoop.service.AbstractService.start(AbstractService.java:194)
at org.apache.hadoop.mapreduce.v2.app.MRAppMaster$6.run(MRAppMaster.java:1761)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at java.base/javax.security.auth.Subject.doAs(Subject.java:423)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1729)
at org.apache.hadoop.mapreduce.v2.app.MRAppMaster.initAndStartAppMaster(MRAppMaster.java:1757)
at org.apache.hadoop.mapreduce.v2.app.MRAppMaster.main(MRAppMaster.java:1691)
Caused by: java.lang.NullPointerException
at org.apache.hadoop.mapreduce.v2.app.client.MRClientService.getHttpPort(MRClientService.java:177)
at org.apache.hadoop.mapreduce.v2.app.rm.RMCommunicator.register(RMCommunicator.java:159)
... 14 more
2019-02-19 21:33:13,954 INFO [main] org.apache.hadoop.util.ExitUtil: Exiting with status 1: org.apache.hadoop.yarn.exceptions.YarnRuntimeException: java.lang.NullPointerException
。以下是我的错误日志。我找不到任何解决方案。请帮忙。
完整日志： https://drive.google.com/file/d/1r29ZbCMWgqhRp1pN_fNf0xCLkvb3IyFi/view?usp=sharing