elasticsearch正常启动连接后，想设置密码确保安全。

vi elasticsearch.yml，把下面标黄项修改为true

---

# Enable security features
xpack.security.enabled: true

xpack.security.enrollment.enabled: true

# Enable encryption for HTTP API client connections, such as Kibana, Logstash, and Agents
xpack.security.http.ssl:
  enabled: false
  keystore.path: certs/http.p12

# Enable encryption and mutual authentication between cluster nodes
xpack.security.transport.ssl:
  enabled: true
  verification_mode: certificate
  keystore.path: certs/transport.p12
  truststore.path: certs/transport.p12
# Create a new cluster with the current node only
# Additional nodes can still join the cluster later
cluster.initial_master_nodes: ["node-1"]

---

回到bin目录下，找到elasticsearch-setup-passwords

执行命令：./elasticsearch-setup-passwords interactive

接下来出现界面如下：

---

[lin@localhost bin]$./elasticsearch-setup-passwords interactive
******************************************************************************
Note: The 'elasticsearch-setup-passwords' tool has been deprecated. This       command will be removed in a future release.
******************************************************************************

Initiating the setup of passwords for reserved users elastic,apm_system,kibana,kibana_system,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]

---

输入y继续执行，接下来就是让你输入密码，注意后面【】中的内容是用户名，后续用此登陆。

---

Enter password for [elastic]: 
Reenter password for [elastic]: 
Enter password for [apm_system]: 
Reenter password for [apm_system]: 
Enter password for [kibana_system]: 
Reenter password for [kibana_system]: 
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_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]

---

输入密码就按回车，直到出现[lin@localhost bin]$

然后再次登陆ES就会要求你输入用户名和密码了。