MiniYarnCluster specifies individual remote log aggregation root dir for each NM. Test code that uses MiniYarnCluster won't be able to get the value of log aggregation root dir. The following code isn't necessary in MiniYarnCluster.
File remoteLogDir =
new File(testWorkDir, MiniYARNCluster.this.getName()
remoteLogDir-nm" + index);
In LogCLIHelpers.java, dumpAllContainersLogs should pass its conf object to FileContext.getFileContext() call.