java.net.ConnectException: Call From s150/192.168.109.150 to s150:8020 failed on connection excepti

启动hive遇到连接的问题：

Exception in thread "main" java.lang.RuntimeException: java.net.ConnectException: Call From s150/192.168.109.150 to s150:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused
        at org.apache.hadoop.hive.ql.session.SessionState.start(SessionState.java:606)
        at org.apache.hadoop.hive.ql.session.SessionState.beginStart(SessionState.java:549)
        at org.apache.hadoop.hive.cli.CliDriver.run(CliDriver.java:750)
        at org.apache.hadoop.hive.cli.CliDriver.main(CliDriver.java:686)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:497)
        at org.apache.hadoop.util.RunJar.run(RunJar.java:221)
        at org.apache.hadoop.util.RunJar.main(RunJar.java:136)
Caused by: java.net.ConnectException: Call From s150/192.168.109.150 to s150:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused

解决方案：重新启动namenode 

hadoop-daemons.sh start namenode