一、异常现象
启动hbase之后，抛出异常，异常信息如下：
master.HMaster: Failed to become active master
hbase java.net.ConnectException: Call From to 9000 failed on connection exception: java.net.ConnectException: Connection refused;
二、异常原因
参考：Hbase: Failed to become active master 的解释：
Can you please check the config "hbase.rootdir". Looks like this config is pointing to NameNode which is in StandBy Node.
Try changing this to point to Active NameNode or change it to value of your config fs.defaultFS in core-site.xml and then the hdfs path.
要保持 hbase-site.xml 中的 hbase.rootdir 的值 与 core-site.xml 中的 fs.default.name 值保持一致，
而在这两个配置文件中的hostname不一致，一个是localhost 一个是rayner。所以出问题了。
三、异常解决
保持所有配置文件中的hostname一致，都为 rayner
四、参考资料
1.Hbase: Failed to become active master