elasticsearch不能使用root启动问题解决

问题：

　　es安装好之后，使用root启动会报错：can not run elasticsearch as root

[root@iZbp1bb2egi7w0ueys548pZ bin]# ./elasticsearch
[--21T09::,][WARN ][o.e.b.ElasticsearchUncaughtExceptionHandler] [] uncaught exception in thread [main]
org.elasticsearch.bootstrap.StartupException: java.lang.RuntimeException: can not run elasticsearch as root
    at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:) ~[elasticsearch-6.0..jar:6.0.]
    at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:) ~[elasticsearch-6.0..jar:6.0.]
    at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:) ~[elasticsearch-6.0..jar:6.0.]
    at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:) ~[elasticsearch-6.0..jar:6.0.]
    at org.elasticsearch.cli.Command.main(Command.java:) ~[elasticsearch-6.0..jar:6.0.]
    at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:) ~[elasticsearch-6.0..jar:6.0.]
    at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:) ~[elasticsearch-6.0..jar:6.0.]
Caused by: java.lang.RuntimeException: can not run elasticsearch as root
    at org.elasticsearch.bootstrap.Bootstrap.initializeNatives(Bootstrap.java:) ~[elasticsearch-6.0..jar:6.0.]
    at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:) ~[elasticsearch-6.0..jar:6.0.]
    at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:) ~[elasticsearch-6.0..jar:6.0.]
    at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:) ~[elasticsearch-6.0..jar:6.0.]
    ...  more

原因：

　　为了安全不允许使用root用户启动

解决：

　　es5之后的都不能使用添加启动参数或者修改配置文件等方法启动了，必须要创建用户

　　1、创建用户：elasticsearch

[root@iZbp1bb2egi7w0ueys548pZ bin]# adduser elasticsearch

　　2、创建用户密码，需要输入两次

[root@iZbp1bb2egi7w0ueys548pZ bin]# passwd elasticsearch

　　3、将对应的文件夹权限赋给该用户

[root@iZbp1bb2egi7w0ueys548pZ local]# chown -R elasticsearch elasticsearch-6.0.0

　　4、切换至elasticsearch用户

[root@iZbp1bb2egi7w0ueys548pZ etc]# su elasticsearch

　　5、进入启动目录启动 /usr/local/elasticsearch-6.0.0/bin  使用后台启动方式：./elasticsearch -d

[elasticsearch@vmt10003 bin]$ ./elasticsearch -d

　　6、启动后测试

　　输入curl ip:9200,如果返回一个json数据说明启动成功

可能遇到的问题

　　1、启动后访问ip:9200没有显示json

　　

[root@iZbp1bb2egi7w0ueys548qZ ~]# curl 10.132.131.51:
curl: () Failed connect to 10.132.131.51:; Connection refused

　　解决：

　　修改elasticsearch.yml文件，添加

　　network.host: 0.0.0.0

　　再次启动就可以了

[root@iZbp1bb2egi7w0ueys548qZ ~]# curl 10.132.131.51:
{
  "name" : "dMD7fZd",
  "cluster_name" : "elasticsearch",
  "cluster_uuid" : "Cy4a99t2Sw2_hnJ_jtdRgA",
  "version" : {
    "number" : "6.0.0",
    "build_hash" : "8f0685b",
    "build_date" : "2017-11-10T18:41:22.859Z",
    "build_snapshot" : false,
    "lucene_version" : "7.0.1",
    "minimum_wire_compatibility_version" : "5.6.0",
    "minimum_index_compatibility_version" : "5.0.0"
  },
  "tagline" : "You Know, for Search"
}