Haproxy 503 服务不可用。没有可用于处理此请求的服务器答案

【问题标题】：Haproxy 503 Service Unavailable . No server is available to handle this requestHaproxy 503 服务不可用。没有可用于处理此请求的服务器
【发布时间】：2016-06-25 04:43:19
【问题描述】：

haproxy 如何处理静态文件，如 .css、.js、.jpeg ？当我使用我的配置文件时，我的浏览器说：

503 服务不可用

没有可用的服务器来处理这个请求。

这是我的配置：

global
  daemon
  group root
  maxconn  4000
  pidfile  /var/run/haproxy.pid
  user root

defaults
  log  global
  option  redispatch
  maxconn 65535
  contimeout 5000
  clitimeout 50000
  srvtimeout 50000
  retries  3
  log 127.0.0.1 local3
  timeout  http-request 10s
  timeout  queue 1m
  timeout  connect 10s
  timeout  client 1m
  timeout  server 1m
  timeout  check 10s


listen dashboard_cluster :8888
  mode http
  stats refresh 5s
  balance roundrobin
  option httpclose
  option tcplog
  #stats realm Haproxy \ statistic
  acl url_static path_beg -i /static
  acl url_static path_end -i .css .jpg .jpeg .gif .png .js
  use_backend static_server if url_static

backend static_server
  mode http
  balance roundrobin
  option httpclose
  option tcplog
  stats realm Haproxy \ statistic
  server controller1 10.0.3.139:80 cookie controller1 check inter 2000 rise 2 fall 5
  server controller2 10.0.3.113:80 cookie controller2 check inter 2000 rise 2 fall 5

我的文件有问题吗？我应该怎么做才能解决这个问题？这个！

【问题讨论】：

标签： haproxy

【解决方案1】：

我认为是什么原因：

没有定义default_backend。 503 将由 HAProxy 发送——这将在日志中显示为 NOSRV。

另一个可能的原因

根据我的经验之一，我收到的 HTTP 503 错误是由于我对相同 IP 和端口 x.x.x.x:80 的 2 个绑定。

frontend test_fe
     bind x.x.x.x:80
     bind x.x.x.x:443 ssl blah

     # more config here

frontend conflicting_fe
     bind x.x.x.x:80

     # more config here

Haproxy 配置检查不会向您发出警告，netstat 不会向您显示 2 个 LISTEN 条目，这就是为什么需要一段时间才能意识到发生了什么。

如果您有 2 个haproxy 服务正在运行，也会发生这种情况。请检查正在运行的进程并终止旧的进程。

【讨论】：

【解决方案2】：

尝试将计时器调大，并检查服务器是否可访问。

来自 HAproxy 文档：

It can happen from many reasons:

The status code is always 3-digit. The first digit indicates a general status :
 - 1xx = informational message to be skipped (eg: 100, 101)
 - 2xx = OK, content is following   (eg: 200, 206)
 - 3xx = OK, no content following   (eg: 302, 304)
 - 4xx = error caused by the client (eg: 401, 403, 404)
 - 5xx = error caused by the server (eg: 500, 502, 503)

  503  when no server was available to handle the request, or in response to
        monitoring requests which match the "monitor fail" condition

  When a server's maxconn is reached, connections are left pending in a queue
  which may be server-specific or global to the backend. In order not to wait
  indefinitely, a timeout is applied to requests pending in the queue. If the
  timeout is reached, it is considered that the request will almost never be
  served, so it is dropped and a 503 error is returned to the client.

如果您在日志中看到 SC：

SC   The server or an equipment between it and haproxy explicitly refused
          the TCP connection (the proxy received a TCP RST or an ICMP message
          in return). Under some circumstances, it can also be the network
          stack telling the proxy that the server is unreachable (eg: no route,
          or no ARP response on local network). When this happens in HTTP mode,
          the status code is likely a 502 or 503 here.

检查 ACL，检查超时...并检查日志，这是最重要的...

【讨论】：