Hadoop集群部署后，出现Yarn的节点都是localhost，从而找不到其他的Node下发任务，出现如下的错误。
ipc.Client: Retrying connect to server: 0.0.0.0/0.0.0.0:10020. Already tried 1 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
在Yarn Web UI中和yarn node -list查看，
022-09-30 11:48:54,735 INFO client.DefaultNoHARMFailoverProxyProvider: Connecting to ResourceManager at hadoop2/192.168.56.2:8032
Total Nodes:3
Node-Id Node-State Node-Http-Address Number-of-Running-Containers
localhost:42975 RUNNING localhost:8042 0
localhost:41913 RUNNING localhost:8042 0
localhost:36595 RUNNING localhost:8042 0
搜索到的解决方案是把/etc/hosts中的localhost项给注释掉，但是尝试后发现不能解决问题。
我的服务器系统是CentOS 8 Stream，最后的解决方案是直接改主机名。
hostnamectl set-hostname hadoop1- 修改
/etc/hostname
