跨集群访问hdfs失败

$ hdfs dfs -ls hdfs://test:8020/hbase
ls: Operation category READ is not supported in state standby. Visit https://s.apache.org/sbnn-error

意思是namenode不可用，查看namenode状态

hdfs-site.xml
  <property>
    <name>dfs.ha.namenodes.nameservice1</name>
    <value>namenode223,namenode47</value>
  </property>

使用命令查看namenode状态，发现主NameNode是在运行的。

$hdfs haadmin -getServiceState namenode223                        
active

此时如果查看namenode是standby模式可以使用以下命令前置切换主备

hdfs haadmin -transitionToActive --forcemanual namenode47

找了半天才发现test:8020是之前的namenode，后来NameNode被我迁移了，换成test2:8020，ok。

总结几个命令，日常维护时使用：

#切换NameNode(强制切换主备)，前提是目前在用的NameNode是standby状态，否则失败
hdfs haadmin -transitionToActive --forcemanual namenode47

#查看NameNode运行状态
hdfs haadmin -getServiceState namenode223              

更多查看
$ hdfs haadmin -help
Usage: DFSHAAdmin [-ns <nameserviceId>]
    [-transitionToActive <serviceId> [--forceactive]]
    [-transitionToStandby <serviceId>]
    [-failover [--forcefence] [--forceactive] <serviceId> <serviceId>]
    [-getServiceState <serviceId>]
    [-checkHealth <serviceId>]
    [-help <command>]

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|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
bin/hadoop command [genericOptions] [commandOptions]