【后台开发与系统运维】 Nginx 的反向代理与负载均衡

反向代理与负载均衡

反向代理： 明确知道要访问哪个网站，借助代理网站来访问就是正向代理；第三方服务器为我们提供了访问服务器集群的内容，但我们不知道是哪台服务器提供的内容，这种代理方式称为反向代理。

负载均衡： 建立很多个服务器，这些服务器组成一个服务器集群，当有请求时中间服务器选择一个压力较小的服务器，然后将请求引入该选择的服务器，这样每个服务器压力趋于平衡，这就是负载均衡。负载均衡是通过反向代理来实现的。

---

Nginx 负载均衡的实现

1.新建一个配置文件fzjh.conf中

<code class="hljs avrasm has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">touch fzjh<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.conf</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

2.编辑配置文件

<code class="hljs axapta has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#设置用户</span>user root;<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#工作衍生的进程数 </span>worker_process <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">4</span>;<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#设置最大连接数</span>events{    worker_connections <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2048</span>;}<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#http部分是负载均衡服务器最重要的部分</span>http{    <span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#设置负载均衡服务器待选列表</span>    <span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#test 服务器列表名称</span>    upstream test{        <span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#服务器地址可以是外网的也可以是内网的</span>        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">server</span> <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">192.168</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">.1</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">.1</span>;        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">server</span> <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">192.168</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">.1</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">.2</span>;    }    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">server</span>{        <span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#监听网站的端口</span>        listen:<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">80</span>;        <span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#location /表示 监听网站的是根目录   </span>        location / {            proxy_pass http:<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//test;</span>        }    }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li></ul>

3.加载配置文件

<code class="hljs lasso has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">/usr/<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">local</span>/nginx/sbin/nginx <span class="hljs-attribute" style="box-sizing: border-box;">-c</span> /usr/<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">local</span>/nginx/conf/fzjh<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>conf</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

---

HTTP Upstream 模块

Upstream模块是Nginx服务器的一个重要模块， Upstream模块在实现 在轮询和客户端ip之间实现后端的负载均衡（即轮询算法）。常用指令有：

ip_hash指令 
采用ip_hash指令，如果客户端请求已经访问了服务器A并登陆，那么第二次请求时，会将该请求通过哈希算法自动定位到该后端服务器中，而不是重新分配到别的服务器中。

<code class="hljs axapta has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">user root;worker_process <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">4</span>;events{    worker_connections <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2048</span>;}http{    upstream test{        <span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#设置ip_hash; 将容易个用户引向同一个后端服务器</span>        ip_hash;         <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">server</span> <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">192.168</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">.1</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">.1</span>;        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">server</span> <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">192.168</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">.1</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">.2</span>;    }    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">server</span>{        listen:<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">80</span>;        <span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#location  </span>        location / {            proxy_pass http:<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//test;</span>        }    }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li></ul>

server指定 
server指定主要用于指定服务器名称和参数。

<code class="hljs axapta has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">user root;worker_process <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">4</span>;events{    worker_connections <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2048</span>;}http{    upstream test{        <span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#weight=2 设置服务器权重 默认是1</span>        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">server</span> <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">192.168</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">.1</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">.1</span> weight=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>;        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">server</span> <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">192.168</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">.1</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">.2</span>;    }    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">server</span>{        listen:<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">80</span>;        <span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#location </span>        location / {            proxy_pass http:<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//test;</span>        }    }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li></ul>

upstream指令 
upstream指令主要用于设置一组在peoxy_pass和fastcgi_pass指令中使用代理服务器，默认负载均衡方式为轮询。

---

其他负载均衡的方法

负载均衡的核心就是建立服务器集群，负载均衡的实现分为硬件实现和软件实现两种方式。

优缺点： 
硬件实现：运行效率非常高，但成本也非常高。 
软件实现：运行效率不如硬件，成本也相对低很多。

Nginx就是通过软件的方式。

原文地址：http://blog.csdn.net/yen_csdn/article/details/52216194

【关于我们】

每天名企社招内推（微信公众号：ourpush），专注于国内各大互联网公司社会招聘内推。每天更新最新互联网名企（包括但不限于BAT网易小米京东乐视携程等名企）内推信息，有技术岗、有产品岗、有运营岗、有设计岗、有交互岗、有销售岗，更有其他N多相关岗位！更多内推信息请扫描以下二维码关注查阅。