執行“hdfs dfs -ls /”出現“Operation category READ is not supported in state standby”報錯解決

問題：

17/07/05 17:15:28 INFO retry.RetryInvocationHandler: Exception while invoking getFileInfo of class ClientNamenodeProtocolTranslatorPB over vm1/192.168.137.121:9000 after 5 fail over attempts. Trying to fail over after sleeping for 19260ms.
java.net.ConnectException: Call From vm1/192.168.137.121 to vm1:9000 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused

解讀

查看報錯信息中，有一個“ConnectionRefused”，初步認爲節點之間連接問題。

然後 jps 查看一下，發現 namenode居然沒有跟着啓動。

癥結

報錯中 vm1 namenode沒有啓動。

解決

hdfs haadmin -getServiceState vm1