Nginx 响应 429，但我的配置中没有配置它

Question

我在 AWS elastic beanstalk 上托管了一个 rails 应用程序，并注意到我的 nginx 服务器在 nginx 日志中返回了 429。问题是，我没有看到 limit_req 的定义位置，所以我很难理解为什么我的 nginx 会返回 429。下面是我的 nginx 配置的副本。

sudo nginx -T
nginx: [warn] conflicting server name "localhost" on 0.0.0.0:80, ignored
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful
# configuration file /etc/nginx/nginx.conf:

user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /var/run/nginx.pid;

# Load dynamic modules. See /usr/share/doc/nginx/README.dynamic.
include /usr/share/nginx/modules/*.conf;

events {
    worker_connections 1024;
}

http {
    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    sendfile            on;
    tcp_nopush          on;
    tcp_nodelay         on;
    keepalive_timeout   65;
    types_hash_max_size 2048;

    include             /etc/nginx/mime.types;
    default_type        application/octet-stream;

    # Load modular configuration files from the /etc/nginx/conf.d directory.
    # See http://nginx.org/en/docs/ngx_core_module.html#include
    # for more information.
    include /etc/nginx/conf.d/*.conf;

    index   index.html index.htm;

    server {
        listen       80 ;
        listen       [::]:80 ;
        server_name  localhost;
        root         /usr/share/nginx/html;

        # Load configuration files for the default server block.
        include /etc/nginx/default.d/*.conf;

        location / {
        }

        # redirect server error pages to the static page /40x.html
        #
        error_page 404 /404.html;
            location = /40x.html {
        }

        # redirect server error pages to the static page /50x.html
        #
        error_page 500 502 503 504 /50x.html;
            location = /50x.html {
        }
    }

}

# configuration file /etc/nginx/conf.d/proxy.conf:
client_max_body_size 20M;
large_client_header_buffers 4 32k;

# configuration file /etc/nginx/conf.d/webapp_healthd.conf:
upstream my_app {
  server unix:///var/run/puma/my_app.sock;
}

log_format healthd '$msec"$uri"'
                '$status"$request_time"$upstream_response_time"'
                '$http_x_forwarded_for';

server {
  listen 80;
  server_name _ localhost; # need to listen to localhost for worker tier

  if ($time_iso8601 ~ "^(\d{4})-(\d{2})-(\d{2})T(\d{2})") {
    set $year $1;
    set $month $2;
    set $day $3;
    set $hour $4;
  }

  access_log  /var/log/nginx/access.log  main;
  access_log /var/log/nginx/healthd/application.log.$year-$month-$day-$hour healthd;

  location / {
    proxy_pass http://my_app; # match the name of upstream directive which is defined above
    proxy_set_header Host $host;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
  }

  location /assets {
    alias /var/app/current/public/assets;
    gzip_static on;
    gzip on;
    expires max;
    add_header Cache-Control public;
  }

  location /public {
    alias /var/app/current/public;
    gzip_static on;
    gzip on;
    expires max;
    add_header Cache-Control public;
  }
}