搭建rocketmq单机环境时踩坑。
遇到问题：在使用命令
nohup sh mqnamesrv &
出现如下错误
java.net.UnknownHostException: hadoop03: hadoop03: unknown error
at java.net.InetAddress.getLocalHost(InetAddress.java:1505)
at org.apache.rocketmq.common.BrokerConfig.localHostName(BrokerConfig.java:201)
at org.apache.rocketmq.common.BrokerConfig.(BrokerConfig.java:39)
at org.apache.rocketmq.broker.BrokerStartup.createBrokerController(BrokerStartup.java:101)
at org.apache.rocketmq.broker.BrokerStartup.main(BrokerStartup.java:56)
Caused by: java.net.UnknownHostException: hadoop03: unknown error
at java.net.Inet4AddressImpl.lookupAllHostAddr(Native Method)
at java.net.InetAddress$2.lookupAllHostAddr(InetAddress.java:928)
at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1323)
at java.net.InetAddress.getLocalHost(InetAddress.java:1500)
... 4 common frames omitted
这是由于启动的时候找不到自己的主机名对应的ip地址而造成的，只需要让在/etc/hosts中添加如上配置，就可以了
解决方案：
按如下命令进行操作
在文件中加入标红的映射。注意：在编辑过程中可能会出现权限问题，需要切换root账户
:wq! 保存退出
使用jps命令查看进程，看是NamesrvStartup是否启动过，如果有关闭它
sh mqshutdown namesrv
再次启动mqnamesrv
nohup sh mqnamesrv &
查看日志，问题解决
