Nginx - architecture articles proxy Agent process flow

Nginx - architecture articles proxy Agent process flow

Development of upstream services and address upstream server command

Function: Specifies have the server address on a set, which address can be domain name, IP address or unix socket address. Can be added to the port after the domain name or IP address, if not a port, use port 80 by default.

upstream backend  {
  server backend1.example.com weight=5;
  server backend2.example.com:8080;
  server unix:/tmp/backend3;
}
 
server {
  location / {
    proxy_pass  http://backend;
  }
}

General parameters:

• backup: Specifies the backup server service, only when the non-backup server is not available, the request will be forwarded on to the server.
• It indicates that a service station has been off the assembly line, not in service.

Weighted Round-Robin load balancing algorithm

Function: access server instructions specify a weighted polling upstream service.

ip_hash and hash module

Function: The IP address of the client is the key hash algorithm mapped to specific upstream server.

upstream backend {
  ip_hash;
  server   backend1.example.com;
  server   backend2.example.com;
  server   backend3.example.com  down;
  server   backend4.example.com;
}

Variable upstream module provides

The packet sent to the command generator upstream thereof:

proxy_method proxy #请求的方法
proxy_set_header #根据指令修改发往上游的请求，若vaule的值为空字符串，则整个header都不会向上游发送
proxy_pass_request_headers on | off  是否放向上游发送请求
proxy_pass_request_body on | off 是否向上游发送body内容

Receiving a user request packet embodiment thereof:

语法: proxy_buffering on|off
默认值: proxy_buffering on
上下文: http, server, location
该指令开启从后端被代理服务器的响应内容缓冲.
如果缓冲区开启,nginx假定被代理的后端服务器会以最快速度响应,并把内容保存在由指令
client_body_buffer_size 

Establish a connection with the upstream server

proxy_connect_timeout 设置超时时间，响应码为502
proxy_next_upstream 上游连接失败，更换一台服务器
proxy_socket_keepalive 上游连接启用Tcp keepalive

http response to receiving the upstream head

语法: proxy_buffer_size the_size
默认值: proxy_buffer_size 4k/8k
上下文: http, server, location

The instructions set the buffer size, the contents of the response obtained from the back-end server agent, will first read is placed here in response to a small part of this header is usually located inside the response content.

Function is disabled in response to the upstream head

proxy_ignore_headers 某些响应头部可以改变nginx的行为，以禁止它们生效

Back upstream failure processing method:

proxy_next_upstream 

Premise: does not send anything to the client

Configuration

• error
• timeout
• invalid header
• http_
• non_idempotent
• off

–

location / {
      proxy_pass         http://app-proxy;
      proxy_next_upstream error timeout http_500 http_502 http_503 http_504;
      proxy_next_upstream_tries 3;
      proxy_connect_timeout 60s;
      proxy_read_timeout 60s;
      proxy_send_timeout 60s;
      proxy_pass_request_headers      on;
      proxy_set_header   Host             $host:$server_port;
      proxy_set_header   X-Real-IP        $remote_addr;
      proxy_set_header   X-Forwarded-For  $proxy_add_x_forwarded_for;
      set $domain default;
 }