利用varnish做Discuz论坛的缓存服务器

实验背景：公司有一台BBS服务器，用的是LNMP的架构搭建的。正好手头有一台空闲的虚拟机，于是想着给BBS前端加一台缓存服务器。于是选定了varnish，搜了很多教程，跌跌撞撞的完成了配置。这其中很多配置的作用我也不是十分了解，这里先给出大体的配置，之后有时间会研究一下其中配置的原理和具体作用。

实验系统：CentOS 6.4_x86_64

实验前提：防火墙和selinux都关闭

实验说明：本实验共有2台主机，IP分配如拓扑

实验软件：varnish-3.0.7-1　　varnish-libs-3.0.7-1

下载地址：http://pan.baidu.com/s/1hq8hgoO

实验拓扑：

　　　　　　　　

一、安装并配置varnish

　　1.在70.186上直接使用yum安装：

yum -y install varnish-3.0.-.el6.x86_64.rpm varnish-libs-3.0.-.el6.x86_64.rpm

　　2.编辑/etc/sysconfig/varnish文件：

vim /etc/sysconfig/varnish
------------------------------------------------>
## Alternative , Advanced configuration

VARNISH_VCL_CONF=/etc/varnish/default.vcl                                      //使用的vcl文件
VARNISH_LISTEN_PORT=                                                         //varnish自己监听的端口
VARNISH_ADMIN_LISTEN_ADDRESS=127.0.0.1                                        //admin管理接口使用的ip
VARNISH_ADMIN_LISTEN_PORT=                                                //admin管理接口使用的端口
VARNISH_SECRET_FILE=/etc/varnish/secret                                       //密码文件
VARNISH_MIN_THREADS=                                                        //最小进程数
VARNISH_MAX_THREADS=                                                      //最大进程数
VARNISH_THREAD_TIMEOUT=                                                    //超过此时间回收空闲进程
VARNISH_STORAGE_SIZE=1G                                                      //存储文件大小
VARNISH_STORAGE="malloc,${VARNISH_STORAGE_SIZE}"                             //指明使用存储的类型及文件
VARNISH_TTL=
DAEMON_OPTS="-a ${VARNISH_LISTEN_ADDRESS}:${VARNISH_LISTEN_PORT} \
             -f ${VARNISH_VCL_CONF} \
             -T ${VARNISH_ADMIN_LISTEN_ADDRESS}:${VARNISH_ADMIN_LISTEN_PORT} \
             -t ${VARNISH_TTL} \
             -w ${VARNISH_MIN_THREADS},${VARNISH_MAX_THREADS},${VARNISH_THREAD_TIMEOUT} \
             -u varnish -g varnish \
             -S ${VARNISH_SECRET_FILE} \
             -s ${VARNISH_STORAGE}"

　　3.编辑vcl文件：

vim /etc/varnish/default.vcl
--------------------------------------------------------->
backend default {
  .host = "192.168.90.186";
  .port = "";
}

acl local {
 "localhost";
 "127.0.0.1";
}

 sub vcl_recv {
     if (req.restarts == ) {
     if (req.http.x-forwarded-for) {
         set req.http.X-Forwarded-For =
         req.http.X-Forwarded-For + ", " + client.ip;
     } else {
         set req.http.X-Forwarded-For = client.ip;
     }
     }

     if(req.request == "PURGE") {
       if (!client.ip ~ local) {
         error  "Not Allowed.";
       }
       return (lookup);
     } 

     if (req.request == "GET" && req.url ~ "\.(jpg|png|gif|swf|jpeg|flv|bmp|gz|tgz|bz2|tbz|js|css|ico)$") {
       unset req.http.cookie;
     }

     if (req.request == "GET" && req.url ~ "\.(js|css).*$") {
       unset req.http.cookie;
     }

     if (req.url ~ "^/images") {
       unset req.http.cookie;
     }  

     if (req.request != "GET" &&
       req.request != "HEAD" &&
       req.request != "PUT" &&
       req.request != "POST" &&
       req.request != "TRACE" &&
       req.request != "OPTIONS" &&
       req.request != "DELETE") {
         return (pipe);
     }

     if (req.request != "GET" && req.request != "HEAD") {
         return (pass);
     }

     if (req.http.Authorization || req.http.Cookie) {
         return (pass);
     }

     if (req.request == "GET" && req.url ~ "\.(php)($|\?)") {
         return (pass);
     }

     return (lookup);
 }

 sub vcl_pipe {
     return (pipe);
 }

 sub vcl_pass {
     if (req.request == "PURGE") {
    error  "PURGE on a passed object";
     }
     return (pass);
 }

 sub vcl_hash {
     hash_data(req.url);
     if (req.http.host) {
         hash_data(req.http.host);
     } else {
         hash_data(server.ip);
     }
     return (hash);
 }

 sub vcl_hit {
     if (!obj.ttl > 0s) {
       return (pass);
     }
     if (req.request == "PURGE") {
         purge;
         error  "Purged.";
     }
     return (deliver);
 }

 sub vcl_miss {
     if (req.request == "PURGE") {
    purge;
    error  "Not in cache";
     }
     return (fetch);
 }

 sub vcl_fetch {
     if (beresp.ttl <= 0s ||
         beresp.http.Set-Cookie ||
         beresp.http.Vary == "*") {
          set beresp.ttl =  s;
          return (hit_for_pass);
     }

      if (beresp.http.Pragma ~ "no-cache" ||
          beresp.http.Cache-Control ~ "no-cache" ||
          beresp.http.Cache-Control ~ "private") {
          return (hit_for_pass);
      }

      if (req.request == "GET" && req.url ~ "\.(bmp|jpeg|jpg|png|gif|svg|png|ico|txt|css|js|html|htm)$") {
          unset beresp.http.set-cookie;
          set beresp.ttl = 1h;
      } else {
          set beresp.ttl = 1800s;
      }

     return (deliver);
 }

 sub vcl_deliver {
     if (obj.hits > ) {
    set resp.http.X-Cache = "Hit Via" + " " + server.hostname;
     } else {
        set resp.http.X-Cache = "Miss Via" + " " + server.hostname;
     }
     return (deliver);
 }

 sub vcl_init {
     return (ok);
 }

 sub vcl_fini {
     return (ok);
 }

　　4.启动varnish，查看端口，并打开浏览器测试：

service varnish start
ss -tnl

　　　　

二、访问测试：

　　1.浏览器打开http://192.168.70.186，并随机访问一些内容：

　　　　

　　2.varnish状态查看：

varnishstat

　　　　

　　3.图表查看：

varnishhist

　　　　

　　4.前端客户端用浏览器的F12功能查看缓存是否命中，这里用chrome演示：

　　　　

　　至此，缓存服务器搭建完毕，这其中还会有些问题，今天先粗浅的演示一下，谢谢大家！QQ：82800452