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詳解CentOS 5.8下varnish-2.1.5的安裝配置

Varnish是一款強大的反向代理加速軟件,關於其工作原理可以參考上圖,其具體流程及VCL語法我這裡就不做說明,網上資料多,大家還可以對照參考其官方網站和《Varnish中文權威指南》。

一、安裝CentOS5.8系統環境下的依耐關系

yum install gcc gcc-c++

yum install automake autoconflibtool ncurses-devel libxslt groff pcre-devel pkgconfig libtool -y

二、下載varnish-2.1.5源碼包,並進行編譯安裝。

cd /usr/local/src

wget  http://repo.varnish-cache.org/source/varnish-2.1.5.tar.gz

tar zxvf varnish-2.1.5.tar.gz

cd varnish-2.1.5.

./autogen.sh

#autogen.sh命令是用來檢查軟件的依耐關系是否滿足,如果報錯的話, 則應該如下

正常所示:

+ aclocal

+ libtoolize --copy --force

+ autoheader

+ automake --add-missing --copy --foreign

+ autoconf

繼續編譯安裝:

./configure --prefix=/usr/local/varnish --enable-dependency-tracking --enable-debugging-symbols --enable-developer-warnings -enable-extra-warnings

make && make install && cd ../

三、創建varnish用戶和組,以及varnish緩存文件和日志存放目錄:

/usr/sbin/groupadd varnish

/usr/sbin/useradd -s /sbin/nologin  -g varnish varnish

mkdir -p /data/varnish/{cache,log}

chown  -R varnish:varnish /data/varnish/{cache,log}

四、我的測試環境是兩台Web機器,IP為192.168.1.103(域名為http://www.yuhongchun027.net)的varnish機器對後端IP為192.168.1.104和192.168.1.105的機器進行反向代理加速,其配置文件/usr/local/varnish/etc/varnish/better.vcl如下所示:

backend rserver1
{
.host ="192.168.1.104";
.port = "80";
.probe = {
.timeout = 5s;          #等待多長時間超時
.interval = 2s;          #檢查時間間隔
.window = 10;         #varnish將維持10個sliding windows的結果
.threshold = 8;         #如果是8次.windows檢查是成功的,就宣告後端的Web機器
是健康的
}
}
backend rserver2
{
.host ="192.168.1.105";
.port = "80";
.probe = {
.timeout = 5s;    
.interval = 2s;   
.window = 10;     
.threshold = 8;
}
}
#指定一個名為realserver組,使用random機制,權重越大,分配的訪問越多,可根據
服務器性能來設定;而round-robin(輪詢)機制是不能指定weight的
director realserver random {
{
.backend = rserver1;
.weight = 5;
}
{
.backend = rserver2;
.weight = 6;
}
}
#定義能清理緩存的機器,這裡只允許本機能用purge的方式清理
acl purge {
"localhost";
"127.0.0.1";
}
sub vcl_recv
{
  if (req.http.host ~"^(.*).yuhongchun027.net")
  {     
     set req.backend =realserver; 
  }  
     else
     {     
       error 200 "Nocahce for this domain"; 
     }           
       if (req.request =="PURGE")
         {        
           if (!client.ip ~purge)
             {           
                error 405"Not allowed.";        
             }
          else
             {
                return (pipe);
             }
}
#獲取客戶端真實IP地址
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;       
}
#對HTTP協議中的GET、HEAD請求進行緩存,對POST請求透過,讓其直接訪問後端Web服
務器。之所以這樣配置,是因為POST請求一般是發送數據給服務器的,需要服務器接
收、處理,所以不緩存;
if (req.request !="GET" && req.request != "HEAD")
{        
return (pipe);
}
if (req.http.Expect)
{       
return (pipe);
}
if (req.http.Authenticate|| req.http.Cookie)
{        
return (pass);
}
if (req.http.Cache-Control~ "no-cache")
{       
return (pass);
}
#對JSP或者PHP文件不緩存
if(req.url ~"\.jsp" || req.url ~ "\.php" )
{        
return (pass);
}
else
{
return (lookup);
}
}sub vcl_pipe
{
return (pipe);
}sub vcl_pass
{
return (pass);
}sub vcl_hash
{
set req.hash += req.url;
if (req.http.host)
{  
set req.hash +=req.http.host;
}
else
{ 
set req.hash +=server.ip;
}
  return (hash);
}sub vcl_hit
{
if (req.request =="PURGE")
{ 
set obj.ttl = 0s;      
error 200"Purged.";
}
if (!obj.cacheable)
{  
return (pass);
}
return (deliver);
}sub vcl_miss
{
if (req.request =="PURGE")
{  
error 404 "Not incache.";
}
if (req.http.user-agent ~"spider")
{   
error 503 "Notpresently in cache";
}
     return (fetch);
}
sub vcl_fetch
{
if (req.request =="GET" && req.url ~ "\.(txt|js)$")
{  
set beresp.ttl = 3600s;
}
else
{  
set beresp.ttl = 30d;
}
if (!beresp.cacheable)
{  
return (pass);
}
if (beresp.http.Set-Cookie)
{ 
return (pass);
}
return (deliver);
}
sub vcl_deliver {
 if (obj.hits > 0) {
   set resp.http.X-Cache= "HIT  FROM www.yuhongchun027.net";
 } else {
   set resp.http.X-Cache= "MISS FROM www.yuhongchun027.net";
 }
return (deliver);
}

 

五、啟動varnish的命令很長,如下所示:

/usr/local/varnish/sbin/varnishd -n /data/varnish/cache -f /usr/local/varnish/etc/varnish/better.vcl -a 0.0.0.0:80 -s

file,/data/varnish/varnish_cache.data,8G  -p user=varnish -p group=varnish -p default_ttl=14400 -p thread_pool_max=8000 -p send_timeout=20 -w

5,51200,30 -T 127.0.0.1:3500  -P /usr/local/varnish/var/varnish.pid

驗證其是否生效可以用curl –I命令,如下所示:

[root@localhost cache]# curl -I http://www.yuhongchun027.net/

以下結果顯示varnish緩存已經起作用了:

HTTP/1.1 200 OK

Server: Apache/2.2.3 (CentOS)

Last-Modified: Wed, 28 Aug 2013 16:27:33 GMT

ETag: "10d242-e-776b6740"

Content-Type: text/html; charset=UTF-8

Content-Length: 14

Date: Wed, 21 Aug 2013 17:47:48 GMT

X-Varnish: 1584727079 1584726982

Age: 10101

Via: 1.1 varnish

Connection: keep-alive

X-Cache: HIT  FROM www.yuhongchun027.net

六、如果vcl配置文件發生改動,想要不重啟而直接reload,可以用如下操作,可以在本機上進行telnet操作,連接3500管理端口:

telnet 127.0.0.1 3500

vcl.load newconfig /usr/local/varnish/etc/varnish/better.vcl

200 13

VCL compiled.

vcl.use newconfig

200 0

如果顯示有200字樣,則表示已經正常reload了,newconfig這個名字是自己定義的,熟悉varnish操作的朋友應該也清楚,通過telnet連接本機還可以進行清理緩存。

七、用varnishadm命令來清理緩存,例子如下所示:

清除所有緩存

/usr/local/varnish/bin/varnishadm -T 192.168.1.103:3500 url.purge *$

清除image目錄下所有緩存

/usr/local/varnish/bin/varnishadm -T 192.168.1.103:3500 url.purge /image/

查看最近清除的詳細url列表,可執行如下命令:

/usr/local/varnish/bin/varnishadm –T 192.168.1.103:3500 purge.list

另外,緩存命中率的高低直接說明了varnish的運行狀態和效果,如果緩存率命中率過低,我們應該對varnish配置進行檢查調整來進行提高,查看其命中率命令如下所示:

/usr/local/varnish/bin/varnishstat -n /data/varnish/cache

八、內核優化如下所示:

編輯/etc/sysctl.conf,添加如下選項:

net.ipv4.tcp_syncookies = 1

net.ipv4.tcp_tw_reuse = 1

net.ipv4.tcp_tw_recycle = 1

net.ipv4.ip_local_port_range = 1024 65000

net.ipv4.tcp_max_syn_backlog = 8192

net.ipv4.tcp_max_tw_buckets = 5000

net.ipv4.tcp_max_syn_backlog = 65536

net.core.netdev_max_backlog =  32768

net.core.somaxconn = 32768

net.core.wmem_default = 8388608

net.core.rmem_default = 8388608

net.core.rmem_max = 16777216

net.core.wmem_max = 16777216

net.ipv4.tcp_timestamps = 0

net.ipv4.tcp_synack_retries = 2

net.ipv4.tcp_syn_retries = 2

net.ipv4.tcp_tw_recycle = 1

net.ipv4.tcp_tw_reuse = 1

net.ipv4.tcp_mem = 94500000 915000000 927000000

net.ipv4.tcp_max_orphans = 3276800

執行如下命令,讓改動配置立即生效:

/sbin/sysctl –p

注意:老生常談的ulimit的問題,這個話題說得太多了,這裡實在不想再提了,記得將在/etc/rc.local添加如下內容:

ulimit –SHn 65535

注意:記得在啟動varnish之前將此命令手動執行一遍(最方便的做法是放進經常運行的監控腳本或服務啟動腳本),另外,在工作中發現,CentOS6.X x86_64下更改ulimit跟CentOS5.X x86_64是不同的,這點也請大家注意。以上即為varnish-2.1.5在CentOS5.8 x86_64下的安裝配置過程,記錄下作為工作筆記,方便以後在新機器上部署,年紀大了,起個備忘作用而矣。

本文出自 “撫琴煮酒” 博客,請務必保留此出處http://andrewyu.blog.51cto.com/1604432/1293169

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