什么是負載均衡？

當一個域名指向多臺web服務器時，添加一臺nginx負載均衡服務器，通過nginx負載均衡即可將來自于客戶端的請求均衡的發送給每臺web服務器，避免單臺服務器負載過高而其余服務器較為空閑的不均衡情況出現

配置nginx負載均衡：

在nginx機器上新建配置文件：

[root@centos02 ~]# vi /etc/nginx/conf.d/test.conf

添加如下內容：

upstream test {  ip_hash;   server 192.168.0.10:80 weight=100;   server 192.168.0.20:80 weight=50; } server {  listen 80;  server_name www.test.com;  location /  {   proxy_pass http://test;   proxy_set_header Host $host;   proxy_set_header X-Real-IP $remote_addr;   proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;  } }

驗證nginx配置并重載：

[root@centos02 ~]# nginx -tnginx: the configuration file /etc/nginx/nginx.conf syntax is oknginx: configuration file /etc/nginx/nginx.conf test is successful[root@centos02 ~]# nginx -s reload

接下來修改客戶端hosts文件將測試的域名www.test.com指向到測試的nginx負載均衡機器的IP即可訪問www.test.com網站。

負載均衡配置示例補充

1.根據請求的文件配置：

upstream aa {       server 192.168.0.10;    server 192.168.0.20;   }upstream bb {     server 192.168.0.100;    server 192.168.0.101; } server {  listen  80;  server_name www.test.com;  location ~ aa.php  {   proxy_pass http://aa/;   proxy_set_header Host $host;   proxy_set_header X-Real-IP  $remote_addr;   proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;  }  location ~ bb.php  {    proxy_pass http://bb/;    proxy_set_header Host $host;    proxy_set_header X-Real-IP  $remote_addr;    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;  }  location /  {    proxy_pass http://bb/;    proxy_set_header Host $host;    proxy_set_header X-Real-IP  $remote_addr;    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;  }}

請求aa.php的，會到aa組，請求bb.php的會到bb組，其他請求全部到bb組，必須要有location / {} ，否則不能正確匹配url

2.根據請求的目錄配置：

upstream aa {       server 192.168.0.10;    server 192.168.0.20;   }upstream bb {     server 192.168.0.100;    server 192.168.0.101; } server {  listen  80;  server_name www.test.com;  location /dir1/  {   proxy_pass http://aa/dir1/;   proxy_set_header Host $host;   proxy_set_header X-Real-IP  $remote_addr;   proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;  }  location /dir2/  {    proxy_pass http://bb/dir2/;    proxy_set_header Host $host;    proxy_set_header X-Real-IP  $remote_addr;    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;  }  location /  {    proxy_pass http://bb/;    proxy_set_header Host $host;    proxy_set_header X-Real-IP  $remote_addr;    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;  }}