worker_processes  1;

events {
    worker_connections  1024;
}

http {
    include       mime.types;
    default_type  application/octet-stream;
    sendfile        on;
    keepalive_timeout  65;

    upstream httpds {
      # 被动式健康检查，表示 10s 内发生 5 次失败后标记为不可用，不会再被请求。
      server 192.168.44.102:80 max_fails=5 fail_timeout=10s;
      server 192.168.44.103:80;
    }

    server {
        listen       80;
        server_name  localhost;

        location / {
            # 发生什么错误时去下一台服务器进行失败重试
            proxy_next_upstream error timeout;
            # 失败重试能消耗的时间
            proxy_next_upstream_timeout 15s;
            # 重试的次数，包括第一次请求。
            proxy_next_upstream_tries 5;
            proxy_pass http://httpds;
        }

        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }
    }
}