黄兵的个人博客

最近问题的一些总结

2020年1月16日，网站平凡无法访问，体现在输入网址之后很久网页也无法显示。

我以为是国际间的网络问题，之后登录服务器ping国内服务器，延迟在10ms之间，好像没有什么问题。

那只能在程序上存在问题。

回忆了今天下午好像根据这篇文章：How to Set DNS Nameservers on Ubuntu 18.04调整了一下服务器的DNS，主要是服务器有些IP需要反向解析，经常解析出现问题，所以将DNS服务器更改成了1.1.1.1，之后今天下午程序平凡出现问题。

重启服务都很难。

查看了一下日志：

Traceback (most recent call last):
File "/var/SMS_Receive/venv/lib/python3.6/site-packages/flask/app.py", line 2446, in wsgi_app
response = self.full_dispatch_request()
File "/var/SMS_Receive/venv/lib/python3.6/site-packages/flask/app.py", line 1951, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/var/SMS_Receive/venv/lib/python3.6/site-packages/flask/app.py", line 1820, in handle_user_exception
  reraise(exc_type, exc_value, tb)
File "/var/SMS_Receive/venv/lib/python3.6/site-packages/flask/_compat.py", line 39, in reraise
  raise value
File "/var/SMS_Receive/venv/lib/python3.6/site-packages/flask/app.py", line 1949, in full_dispatch_request
  rv = self.dispatch_request()
File "/var/SMS_Receive/venv/lib/python3.6/site-packages/flask/app.py", line 1935, in dispatch_request
  return self.view_functions[rule.endpoint](**req.view_args)
File "/var/SMS_Receive/app/decorators.py", line 40, in decorated_function
  rabbit_mq_util.rabbit_mq_access_records()
File "/var/SMS_Receive/app/rabbit_mq_until.py", line 41, in rabbit_mq_access_records
  conn_broker = pika.BlockingConnection(conn_params)
File "/var/SMS_Receive/venv/lib/python3.6/site-packages/pika/adapters/blocking_connection.py", line 359, in __init__
  self._impl = self._create_connection(parameters, _impl_class)
File "/var/SMS_Receive/venv/lib/python3.6/site-packages/pika/adapters/blocking_connection.py", line 450, in _create_connection
  raise self._reap_last_connection_workflow_error(error)
File "/var/SMS_Receive/venv/lib/python3.6/site-packages/pika/adapters/utils/selector_ioloop_adapter.py", line 564, in _resolve
  self._flags)
File "/usr/lib/python3.6/socket.py", line 745, in getaddrinfo
  for res in _socket.getaddrinfo(host, port, family, type, proto, flags):
Jan 16 18:25:25 VM-0-7-ubuntu gunicorn[24356]: socket.gaierror: [Errno -3] Temporary failure in name resolution

最后出现：[Errno -3] Temporary failure in name resolution，通过这篇文章：python telnet 登录，作者说是DNS解析IP地址错误，那就没错，应该是我设置了DNS服务器，导致解析需要连接到国外解析，解析异常缓慢，同时这里是使用RabbitMQ队列，但是RabbitMQ服务器使用的是国内的域名。

同时，RabbitMQ也是在主线程上进行，导致程序卡死。

最后将DNS配置重新恢复到原来配置，问题解决。

在正式环境中改配置参数需要小心，尤其是系统底层参数，有可能导致上层软件的问题。

黄兵个人博客原创。

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