java.io.IOException: Can't get Master Kerberos principal for use as renewer 错误解决

最近在集群中执行调度任务，或者是 在集群中执行 hadoop distcp 命令都会报这样的问题。

java.io.IOException: Can't get Master Kerberos principal for use as renewer
- at org.apache.hadoop.mapreduce.security.TokenCache.obtainTokensForNamenodesInternal(TokenCache.java:133)
 at org.apache.hadoop.mapreduce.security.TokenCache.obtainTokensForNamenodesInternal(TokenCache.java:100)
at org.apache.hadoop.mapreduce.security.TokenCache.obtainTokensForNamenodes(TokenCache.java:80)
 at org.apache.hadoop.tools.SimpleCopyListing.validatePaths(SimpleCopyListing.java:191)
at org.apache.hadoop.tools.CopyListing.buildListing(CopyListing.java:85)
 at org.apache.hadoop.tools.GlobbedCopyListing.doBuildListing(GlobbedCopyListing.java:90)
 at org.apache.hadoop.tools.CopyListing.buildListing(CopyListing.java:86)
 at org.apache.hadoop.tools.DistCp.createInputFileListing(DistCp.java:429)
 at org.apache.hadoop.tools.DistCp.prepareFileListing(DistCp.java:91)
at org.apache.hadoop.tools.DistCp.execute(DistCp.java:181)
at org.apache.hadoop.tools.DistCp.run(DistCp.java:143)
 at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
at org.apache.hadoop.tools.DistCp.main(DistCp.java:493)

经过源码分析：

 代码中会去读取yarn的配置文件，如果读不到yarn的配置文件，就会报这样的错误。

解决方法：

与机器的HADOOP_CLASSPATH 环境变量有关，我们是有同事添加了错误的HADOOP_CLASSPATH 环境变量，最终在机器上移掉该环境变量，就可以工作了