1，首先安装nginx

        yum install -y nginx

2，生成密钥文件

        安装htpasswd工具

        yum install -y httpd-tools

        生成密钥文件，prometheus为用户名

        htpasswd -c /etc/nginx/conf.d/passwd prometheus

3，修改nginx配置文件nginx.conf，增加如下内容

    upstream  vmselect {
        server  10.250.5.74:8901 weight=5 ;
        server  10.250.5.75:8902 weight=5 ;
        server  10.250.5.76:8903 weight=5 ;
    }

    server {
        listen 8900;
        server_name _;
        auth_basic "authentication";                # 开启基本认证
        auth_basic_user_file /etc/nginx/conf.d/passwd;      # 密码文件
        location / {
            proxy_pass http://vmselect/select/0/prometheus/;
        }
    }

    upstream vminsert {
        server  10.250.5.74