執行hadoop fs -ls /命令報錯是怎么回事?。?/h1>

執行?hadoop fs -ls /命令后顯示如下：

-ls: java.net.UnknownHostException: gn80

Usage: hadoop fs [generic options]

? ? ? ? [-appendToFile <localsrc> ... <dst>]

? ? ? ? [-cat [-ignoreCrc] <src> ...]

? ? ? ? [-checksum <src> ...]

? ? ? ? [-chgrp [-R] GROUP PATH...]

? ? ? ? [-chmod [-R] <MODE[,MODE]... | OCTALMODE> PATH...]

? ? ? ? [-chown [-R] [OWNER][:[GROUP]] PATH...]

? ? ? ? [-copyFromLocal [-f] [-p] [-l] [-d] <localsrc> ... <dst>]

? ? ? ? [-copyToLocal [-f] [-p] [-ignoreCrc] [-crc] <src> ... <localdst>]

? ? ? ? [-count [-q] [-h] [-v] [-t [<storage type>]] [-u] [-x] <path> ...]

? ? ? ? [-cp [-f] [-p | -p[topax]] [-d] <src> ... <dst>]

? ? ? ? [-createSnapshot <snapshotDir> [<snapshotName>]]

? ? ? ? [-deleteSnapshot <snapshotDir> <snapshotName>]

? ? ? ? [-df [-h] [<path> ...]]

? ? ? ? [-du [-s] [-h] [-x] <path> ...]

? ? ? ? [-expunge]

? ? ? ? [-find <path> ... <expression> ...]

? ? ? ? [-get [-f] [-p] [-ignoreCrc] [-crc] <src> ... <localdst>]

? ? ? ? [-getfacl [-R] <path>]

? ? ? ? [-getfattr [-R] {-n name | -d} [-e en] <path>]

? ? ? ? [-getmerge [-nl] [-skip-empty-file] <src> <localdst>]

? ? ? ? [-help [cmd ...]]

? ? ? ? [-ls [-C] [-d] [-h] [-q] [-R] [-t] [-S] [-r] [-u] [<path> ...]]

? ? ? ? [-mkdir [-p] <path> ...]

? ? ? ? [-moveFromLocal <localsrc> ... <dst>]

? ? ? ? [-moveToLocal <src> <localdst>]

? ? ? ? [-mv <src> ... <dst>]

? ? ? ? [-put [-f] [-p] [-l] [-d] <localsrc> ... <dst>]

? ? ? ? [-renameSnapshot <snapshotDir> <oldName> <newName>]

? ? ? ? [-rm [-f] [-r|-R] [-skipTrash] [-safely] <src> ...]

? ? ? ? [-rmdir [--ignore-fail-on-non-empty] <dir> ...]

? ? ? ? [-setfacl [-R] [{-b|-k} {-m|-x <acl_spec>} <path>]|[--set <acl_spec> <path>]]

? ? ? ? [-setfattr {-n name [-v value] | -x name} <path>]

? ? ? ? [-setrep [-R] [-w] <rep> <path> ...]

? ? ? ? [-stat [format] <path> ...]

? ? ? ? [-tail [-f] <file>]

? ? ? ? [-test -[defsz] <path>]

? ? ? ? [-text [-ignoreCrc] <src> ...]

? ? ? ? [-touchz <path> ...]

? ? ? ? [-truncate [-w] <length> <path> ...]

? ? ? ? [-usage [cmd ...]]

Generic options supported are

-conf <configuration file>? ? ?specify an application configuration file

-D <property=value>? ? ? ? ? ? use value for given property

-fs <file:///|hdfs://namenode:port> specify default filesystem URL to use, overrides 'fs.defaultFS' property from configurations.

-jt <local|resourcemanager:port>? ? specify a ResourceManager

-files <comma separated list of files>? ? specify comma separated files to be copied to the map reduce cluster

-libjars <comma separated list of jars>? ? specify comma separated jar files to include in the classpath.

-archives <comma separated list of archives>? ? specify comma separated archives to be unarchived on the compute machines.

The general command line syntax is

command [genericOptions] [commandOptions]

Usage: hadoop fs [generic options] -ls [-C] [-d] [-h] [-q] [-R] [-t] [-S] [-r] [-u] [<path> ...]

請問這是怎么回事？