原因：因为太懒在主节点启动成功之后直接把它copy了一份，导致的这个错误，因为服务器启动会创建部分文件。
解决：从tar包重新解压一个就ok了。
[o.e.d.z.ZenDiscovery ] [slave1] failed to send join request to master [{master}{BLEigXhhRoOaONB-_LEHlQ}{j9QILYaeTLyZ8_qxWurT8w}{127.0.0.1}{127.0.0.1:9300}{ml.machine_memory=8589934592, ml.max_open_jobs=20, xpack.installed=true, ml.enabled=true}], reason [RemoteTransportException[[master][127.0.0.1:9300][internal:discovery/zen/join]]; nested: IllegalArgumentException[can't add node {slave1}{BLEigXhhRoOaONB-_LEHlQ}{nVq9upw4QL2oaOeVRhrnaw}{127.0.0.1}{127.0.0.1:9301}{ml.machine_memory=8589934592, ml.max_open_jobs=20, xpack.installed=true, ml.enabled=true}, found existing node {master}{BLEigXhhRoOaONB-_LEHlQ}{j9QILYaeTLyZ8_qxWurT8w}{127.0.0.1}{127.0.0.1:9300}{ml.machine_memory=8589934592, xpack.installed=true, ml.max_open_jobs=20, ml.enabled=true} with the same id but is a different node instance]; ]