Hadoop版本是：
[hadoop@L-6140-BBS: ~/src/hadoop/conf]$ hadoop version
Hadoop 0.20.1+169.89
我运行mradmin freshNodes，但看起来没有这个命令
[hadoop@L-6140-BBS: ~/src/hadoop/conf]$ hadoop mradmin -refreshNodes
efreshNodes: Unknown command
Usage: java MRAdmin
[-refreshServiceAcl]
[-help [cmd]]
Generic options supported are
-conf <configuration file> specify an application configuration file
-D <property=value> use value for given property
-fs <local|namenode:port> specify a namenode
-jt <local|jobtracker:port> specify a job tracker
-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
bin/hadoop command [genericOptions] [commandOptions]