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