⑨nginx 负载均衡

upstream 七层负载模块

Syntax: 	upstream name { ... }
Default: 	—
Context: 	http

 Example:

    upstream backend {
        server backend1.example.com weight=5;
        server 127.0.0.1:8080       max_fails=3 fail_timeout=30s;
        server unix:/tmp/backend3;

        server backup1.example.com  backup;
    }

例子：

upstream rongbiz {              --- 指定负载均衡主机信息
            server  10.0.0.7:80;
            server  10.0.0.8:80;
            server  10.0.0.9:80;
        }
       
        server {
            listen        80;
            server_name   www.rongbiz.com;
        location / {
            proxy_pass http://rongbiz;  --- 将请求反向代理发送给哪个集群
            include proxy_params;     
         }
       }

Nginx负载均衡状态配置

后端服务器在负载均衡调度中的状态

状态	概述
down	当前的server暂时不参与负载均衡
backup	预留的备份服务器
max_fails	允许请求失败的次数
fail_timeout	经过max_fails失败后, 服务暂停时间
max_conns	限制最大的接收连接数

测试backup以及down状态

upstream load_pass {
    server 192.168.56.11:8001 down;
    server 192.168.56.12:8002 backup;
    server 192.168.56.13:8003 max_fails=1 fail_timeout=10s;
}

location  / {
    proxy_pass http://load_pass;
    include proxy_params;
}

Nginx负载均衡调度策略

调度算法	概述
轮询	按时间顺序逐一分配到不同的后端服务器(默认)
weight	加权轮询,weight值越大,分配到的访问几率越高
ip_hash	每个请求按访问IP的hash结果分配,这样来自同一IP的固定访问一个后端服务器
url_hash	按照访问URL的hash结果来分配请求,是每个URL定向到同一个后端服务器
least_conn	最少链接数,那个机器链接数少就分发
hash关键数值	hash自定义的key

Nginx负载均衡权重轮询具体配置

upstream load_pass {
    server 192.168.56.11:8001;
    server 192.168.56.12:8002 weight=5;
    server 192.168.56.13:8003;
}

Nginx负载均衡ip_hash具体配置

//如果客户端都走相同代理, 会导致某一台服务器连接过多
upstream load_pass {
    ip_hash;
    server 192.168.56.11:8001;
    server 192.168.56.12:8002;
    server 192.168.56.13:8003;
}
//如果出现通过代理访问会影响后端节点接收状态均衡

Nginx负载均衡url_hash具体配置

upstream load_pass {
    hash $request_uri;
    server 192.168.56.11:8001;
    server 192.168.56.12:8002;
    server 192.168.56.13:8003;
}

//针对三台服务器添加相同文件
/soft/code1/url1.html url2.html url3.html
/soft/code2/url1.html url2.html url3.html
/soft/code3/url1.html url2.html url3.html

nginx四层负载均衡

Nginx负载均衡TCP配置

Nginx四层代理仅能存在于main段

stream {
        upstream ssh_proxy {
                hash $remote_addr consistent;
                server 192.168.56.103:22;
        }
        upstream mysql_proxy {
                hash $remote_addr consistent;
                server 192.168.56.103:3306;
        }
    server {
        listen 6666;
        proxy_connect_timeout 1s;
        proxy_timeout 300s;
        proxy_pass ssh_proxy;
    }
    server {
        listen 5555;
        proxy_connect_timeout 1s;
        proxy_timeout 300s;
        proxy_pass mysql_proxy;
    }
}