haproxy 背后的 nginx 问题

Question

我正在托管一个 ajax 网站（AngularJS），它的资产/部分驻留在运行 haproxy 后面 nginx 的静态资产服务器上。

我的设置如下：

Web -> Haproxy -> App (custom) and Static (nginx) servers

现在，有时会发生特定资产（HTML 部分）无法加载，或者仅在一次或多次浏览器刷新后才开始加载（Chrome 的网络 devtools 显示该请求处于“待处理”状态）。

我不知道是什么原因造成的，因为资产/部分都在同一个文件夹中，而其他的都加载正常。

以下是 2 个配置，也许你能发现一些可疑之处？
我该如何有效地调试此类问题？

haproxy.cfg.j2：（这是一个 Jinja2 模板，因此不要对模板语法感到困惑）

# requires haproxy 1.5+

global
  log 127.0.0.1 local0
  log 127.0.0.1 local1 notice
  maxconn 4096
  user haproxy
  group haproxy
  daemon


defaults
  log global
  mode http
  maxconn 4096

  # Add x-forwarded-for header
  option forwardfor
  option redispatch
  option dontlognull
  option http-server-close

  timeout connect         5s
  timeout client          30s
  timeout server          30s
  timeout tunnel          15m
  timeout http-keep-alive 1s
  timeout http-request    15s
  timeout queue           30s
  timeout tarpit          60s


frontend public
  mode http

  bind :80
  bind :443 ssl crt /etc/ssl/haproxy.pem

  acl is_app    hdr_end(Host) -i api.example.com api-stage.example.com
  acl is_static hdr_end(Host) -i example.com stage.example.com
  acl is_io     hdr_end(Host) -i example.io stage.example.io
  acl is_ws     hdr(Upgrade)  -i WebSocket

  # Redirect HTTP to HTTPS
  #
  # Make sure we don't redirect WebSocket requests otherwise
  # the browser might complain because of the returned 302 status
  #
  redirect scheme https if !{ ssl_fc } is_app !is_ws
  redirect scheme https if !{ ssl_fc } is_static !is_ws

  # To force example.io on SSL we'd need a 2nd certificate
  #
  # redirect scheme https if !{ ssl_fc } is_io !is_ws

  use_backend bk_notify if is_ws
  use_backend bk_app if is_app
  use_backend bk_files if is_io

  default_backend bk_static


backend bk_static
  reqadd X-Forwarded-Proto:\ https
  balance leastconn
  {% for m in servers.static %}
  server {{ m.name }} {{ m.private_ip_address }}:80 weight 1 maxconn 1024 check
  {% endfor %}


backend bk_app
  reqadd X-Forwarded-Proto:\ https
  balance hdr(Authorization)
  {% for m in servers.app %}
  server {{ m.name }} {{ m.private_ip_address }}:8001 weight 1 maxconn 1024 check
  {% endfor %}


backend bk_notify
  balance leastconn
  {% for m in servers.app %}
  server {{ m.name }} {{ m.private_ip_address }}:8001 weight 1 maxconn 1024 check
  {% endfor %}


backend bk_files
  reqadd X-Forwarded-Proto:\ https
  balance leastconn
  {% for m in servers.app %}
  server {{ m.name }} {{ m.private_ip_address }}:8002 weight 1 maxconn 1024 check
  {% endfor %}


listen stats :1936
  mode http
  stats enable
  stats hide-version
  stats realm Haproxy\ Statistics
  stats uri /
  stats auth iwant:thestats

nginx.conf：

user www-data;
worker_processes 4;
pid /var/run/nginx.pid;

events {
    worker_connections 768;
    # multi_accept on;
}

http {    
    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;

    access_log /var/log/nginx/access.log;
    error_log /var/log/nginx/error.log;

    gzip on;
    gzip_disable "msie6";
    gzip_vary on;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_buffers 16 8k;
    gzip_http_version 1.1;
    gzip_types text/plain text/css application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript;

    server {
        #listen   80; ## listen for ipv4; this line is default and implied
        #listen   [::]:80 default ipv6only=on; ## listen for ipv6

        root /usr/share/nginx/www;
        index index.html index.htm;
        server_name localhost;

        location / {
            try_files $uri $uri/ /index.html;
        }

        # This block will catch static file requests, such as images, css, js
        # The ?: prefix is a 'non-capturing' mark, meaning we do not require
        # the pattern to be captured into $1 which should help improve performance
        location ~* \.(?:ico|css|js|gif|jpe?g|png|woff|eot|ttf|svg)$ {
            expires max;
            add_header Pragma public;
            add_header Cache-Control "public, must-revalidate, proxy-revalidate";
        }

        # Content that should not be cached
        location ~* \.(?:html|htm|txt)$ {
            expires 0;
            add_header Cache-Control "private, must-revalidate, proxy-revalidate";
        }

        # this prevents hidden files (beginning with a period) from being served
        location ~ /\. {
            access_log off;
            log_not_found off;
            deny all;
        }
    }
}