Nginx负载均衡服务器实现会话粘贴

1、 使用Nginx 的ip_hash作为负载均衡服务并支持Session sticky
Nginx可以通过ip_hash实现客户端的请求总是分发到同一个服务器。
因为网站或系统经常是与session有关的，需要用sessionid或cookie来识别用户验证用户。
例如：

upstream  backend  {
    ip_hash;

    server   backend1.example.com max_fails=1  fail_timeout=3600s;
    server   backend2.example.com max_fails=1  fail_timeout=3600s;
    server   backend3.example.com  down;
    server   backend4.example.com max_fails=1  fail_timeout=3600s;
}
server {
    location / {
        proxy_pass  http://backend;
    }
}

fail_timeout：为失败尝试max_fails次数后，暂停分发该服务器的时间

2、 使用nginx sticky第三方模块实现基于cookie的负载均衡
a.nginx sticky 模块工作流程图

b.下载安装nginx sticky
下载地址：http://code.google.com/p/nginx-sticky-module/downloads/list
目前共有2个版本，一个是1.0，一个是1.1，1.0已经寿终正寝了.1.1增加了权重的参数.

安装nginx + sticky模块

# wget http://nginx-sticky-module.googlecode.com/files/nginx-sticky-module-1.1.tar.gz
# tar -xzvf nginx-sticky-module-1.1.tar.gz

# wget http://nginx.org/download/nginx-1.0.6.tar.gz
# tar -czvf nginx-1.0.6
# cd nginx-1.0.6
# ./configure --prefix=/usr/local/nginx-1.0.6 --with-http_stub_status_module --with-http_ssl_module --with-http_realip_module --add-module=../nginx-sticky-module-1.1
# make
# make install

c.配置nginx sticky
nginx 的upstream使用sticky,如下

upstream cluster_test {
     sticky;
     server 192.168.100.209:80;
     server 192.168.100.225:80;
}

配置虚拟主机（以下有配置的可以忽略掉）

server {
        listen        80;
        server_name     test.ttlsa.com;
        index index.jsp;

        access_log /data/logs/nginx/test.ttlsa.com_access.log main;

        set $proxy_pass cluster_test;

        location /
        {
                proxy_pass http://$proxy_pass;
                include proxy.conf;
                add_header Cache-Control no-store;
        }

}

3、使用nginx的map指令根据cookie分流：
a.用nginx的map指令根据cookie分流

map $COOKIE_abcdexpid $group {
  ~*1$	apache001;
  ~*2$	apache002;
  default	root;
}
 
upstream apache001 {
  server 192.168.1.1:8080 weight=1 max_fails=1 fail_timeout=30s;
}
 
upstream apache002 {
  server 192.168.1.2:8080 weight=1 max_fails=1 fail_timeout=30s;
}
 
upstream root {
  server 192.168.1.0:8080 weight=1 max_fails=1 fail_timeout=30s;
}
 
server {
  listen       8080;
  server_name  neoremind.net;
 
  log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
            '$status $body_bytes_sent "$http_referer" "group=$group"'
            '"$http_user_agent" $gzip_ratio $request_time "$http_x_forwarded_for"';
 
  access_log  logs/access_log main;
  error_log   logs/error_log;
 
  location / {
        proxy_pass http://$group;
    proxy_set_header X-Forwarded-For $remote_addr;
    }	
}

b.利用set和if…else… 根据cookie分流

upstream apache001 {
  server 192.168.1.1:8080 weight=1 max_fails=1 fail_timeout=30s;
}
 
upstream apache002 {
  server 192.168.1.2:8080 weight=1 max_fails=1 fail_timeout=30s;
}
 
upstream root {
  server 192.168.1.0:8080 weight=1 max_fails=1 fail_timeout=30s;
}
 
server {
  listen       8080;
  server_name  beidoutest.baidu.com;
 
  #match cookie
  set $group "root";
  if ($http_cookie ~* "abcdexpid=([^;]+)(1$)"){
    set $group apache001;
  }
  if ($http_cookie ~* "abcdexpid=([^;]+)(2$)"){
    set $group apache002;
  }
 
  log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
            '$status $body_bytes_sent "$http_referer" "group=$group"'
            '"$http_user_agent" $gzip_ratio $request_time "$http_x_forwarded_for"';
 
  access_log  logs/access_log main;
  error_log   logs/error_log;
 
  location / {
    proxy_pass http://$group;
    proxy_set_header X-Forwarded-For $remote_addr;
  }
}

c.nginx1.7.2版本后提供的hash方法：

# http context  
upstream backend_hosts {      
hash $cookie_jsessionid consistent;      
server host1.example.com;     
server host2.example.com;     
server host3.example.com; 
}