elasticsearch 设置密码
1.进入到lelasticsearch目录下的config目录，找到elasticsearch.yml文件，在里面添加如下命令并重启：
xpack.security.enabled: true
xpack.license.self_generated.type: basic
xpack.security.transport.ssl.enabled: true
2.执行设置用户名和密码的命令,这里需要为4个用户分别设置密码，elastic, kibana, logstash_system,beats_system:
bin/elasticsearch-setup-passwords interactive
设置密码时出现的：
[es@k8snode2 elasticsearch-7.3.0]$ ./bin/elasticsearch-setup-passwords interactive
Initiating the setup of passwords for reserved users elastic,apm_system,kibana,logstash_system,beats_system,remote_monitoring_user.
You will be prompted to enter passwords as the process progresses.
Please confirm that you would like to continue [y/N]y
Enter password for [elastic]:
Reenter password for [elastic]:
Passwords do not match.
Try again.
Enter password for [elastic]:
Reenter password for [elastic]:
Enter password for [apm_system]:
Reenter password for [apm_system]:
Enter password for [kibana]:
Reenter password for [kibana]:
Enter password for [logstash_system]:
Reenter password for [logstash_system]:
Enter password for [beats_system]:
Reenter password for [beats_system]:
Enter password for [remote_monitoring_user]:
Reenter password for [remote_monitoring_user]:
Changed password for user [apm_system]
Changed password for user [kibana]
Changed password for user [logstash_system]
Changed password for user [beats_system]
Changed password for user [remote_monitoring_user]
Changed password for user [elastic]
其中，用户权限分别如下：
elastic 账号：拥有 superuser 角色，是内置的超级用户。
kibana 账号：拥有 kibana_system 角色，用户 kibana 用来连接 elasticsearch 并与之通信。Kibana 服务器以该用户身份提交请求以访问集群监视 API 和 .kibana 索引。不能访问 index。
logstash_system 账号：拥有 logstash_system 角色。用户 Logstash 在 Elasticsearch 中存储监控信息时使用。
修改密码
curl -H "Content-Type:application/json" -XPOST -u elastic
'http://127.0.0.1:9200/_xpack/security/user/elastic/_password' -d '{ "password" : "123456" }'