场景描述

单机缺点

当量上来后由于单机请求压力大，存在单点故障等问题

负载优点

降低单点故障
提高服务器处理能力
灵活控制请求流量
隐藏真实服务器地址

负载均衡

如下图

Nginx配置

配置如下

#user  nobody;
worker_processes  8;
worker_rlimit_nofile 65535;


events {
    use epoll;
    worker_connections  8192;
}


#http核心
http {
    include       mime.types;
    default_type  application/octet-stream;
    client_max_body_size 10M;
    client_body_buffer_size 256k;

    #日志格式
    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                                        '"$status" $body_bytes_sent "$http_referer" '
                                        '"$http_user_agent" "$http_x_forwarded_for" '
                                        '"$gzip_ratio" $request_time $bytes_sent $request_length';

    access_log  logs/access.log  main;
    sendfile        on;
    keepalive_timeout  65;

    upstream backend{
        server 192.168.1.1 weight=1;
        server 192.168.1.1 weight=1;
    }

    #虚拟服务器
    server {
        listen       80;
        server_name  www.go008.com;


        location / {
            root   html;
            index  index.html index.htm;
            proxy_pass http://backend;
            proxy_redirect off;
            proxy_set_header Host $http_host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header Cookie $http_cookie;
            chunked_transfer_encoding off;
            proxy_pass_header Set-Cookie;
        }

        #error_page  404              /404.html;

        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }
    }
}

白话描述

当用户请求www.go008.com的时候，由于该域名IP地址解析到负载均衡nginx所在服务器
由于虚拟服务器server配置了监听www.go008.com:80
请求被分发到proxy_pass配置的反向代理模块backend
upstream根据配置将请求分发到后端真实服务器