背景：将节点设置为1后RED消失。
elasticsearch单个node节点写入数据-CSDN博客
elasticsearch 写入新数据测试（二）-CSDN博客
参数设置如下：
discovery.seed_hosts: ["81.70.16.18"]
cluster.initial_master_nodes: ["node-1"]
gateway.recover_after_nodes: 1
xpack.security.enabled: true
然后重启，设置密码，此时发现RED消失了
./bin/elasticsearch-setup-passwords interactive
Initiating the setup of passwords for reserved users elastic,apm_syste
