varnish開源項目是2006年釋出的第一個版本0.9.距今已經八年多了，此文檔之前也提過varnish還不穩定，那是2007年時候編寫的，現在的varnish已經很健壯。很多門戶網站已經部署了varnish，并且反應都很好，甚至反應比squid還穩定，且效率更高，資源占用更少。相信在反向代理，web加速方面，varnish已經有足夠能力代替squid。
Varnish 的作者Poul-Henning Kamp是FreeBSD（BSD UNIX分支的開發者）的核心開發者之一，他認為現在的計算機比起1975年已經複雜許多。在1975年時，儲存媒介隻有兩種：記憶體與硬碟。但現在計算機系統的記憶體除了主存外，還包括了CPU内的L1、L2，甚至有L3快取。硬碟上也有自己的快取裝置，是以Squid Cache自行處理物件替換的架構不可能得知這些情況而做到最佳化，但作業系統可以得知這些情況，是以這部份的工作應該交給作業系統處理，這就是 Varnish cache設計架構。
一個典型的例子：
挪威大的線上報紙 Verdens Gang 使用3台Varnish代替了原來的12台Squid，性能比以前更好
下邊進行varnish的安裝
varnish官網：https://www.varnish-cache.org
varnish下載下傳：https://www.varnish-cache.org/releases
varnish支援的平台（作業系統）有：
- Debian
- FreeBSD
- Red Hat Enterprise Linux 5/6
- Ubuntu
此處以RHEL6為準測試
varnish已經對RHEL&CentOS支援很好，支援線上yum安裝指令如下：
#rpm --nosignature -i http://repo.varnish-cache.org/redhat/varnish-3.0/el6/noarch/varnish-release-3.0-1.el6.noarch.rpm
rpm直接遠端安裝這個包會生成yum源的配置檔案
#
yum install varnish
#即可安裝varnish chache server
此處我的機器不能連接配接到網際網路，所有采用源碼包安裝
源碼包下載下傳位址：http://repo.varnish-cache.org/source/varnish-3.0.3.tar.gz
RPM包下載下傳位址：http://repo.varnish-cache.org/redhat/varnish-3.0/el6/x86_64/
下邊先說源碼包的安裝：
[[email protected] ~]# cd /usr/src/ && tar -zxvf varnish-3.0.3.tar.gz && cd varnish-3.0.3 #将下載下傳的包mv到 /usr/src然後解包再進入varnish的安裝目錄
[[email protected] varnish-3.0.3]# yum -y install gcc glib gcc-c++ pcre-devel #安裝依賴包為了相容正規表達式
[[email protected] varnish-3.0.3]# ./configure --prefix=/usr/local/varnish #編譯安裝的配置
[[email protected] varnish-3.0.3]# make && make install #編譯和安裝
至此安裝完成，下邊簡單叙述一下rpm包的安裝過程：
擷取包
# wget http://repo.varnish-cache.org/redhat/varnish-3.0/el6/x86_64/varnish-3.0.4-1.el6.x86_64.rpm && wget http://repo.varnish-cache.org/redhat/varnish-3.0/el6/x86_64/varnish-agent-1.16-0.el6.x86_64.rpm && wget http://repo.varnish-cache.org/redhat/varnish-3.0/el6/x86_64/varnish-debuginfo-3.0.4-1.el6.x86_64.rpm && wget http://repo.varnish-cache.org/redhat/varnish-3.0/el6/x86_64/varnish-docs-3.0.4-1.el6.x86_64.rpm && wget http://repo.varnish-cache.org/redhat/varnish-3.0/el6/x86_64/varnish-libs-3.0.4-1.el6.x86_64.rpm && wget http://repo.varnish-cache.org/redhat/varnish-3.0/el6/x86_64/varnish-libs-devel-3.0.4-1.el6.x86_64.rpm
以上包包含動态連結庫包，文檔包，開發依賴包等等
[[email protected] RPMvarnish]# rpm -ivh varnish-debuginfo-3.0.4-1.el6.x86_64.rpm
Preparing... ########################################### [100%]
1:varnish-debuginfo ########################################### [100%]
[[email protected] RPMvarnish]# rpm -ivh varnish-docs-3.0.4-1.el6.x86_64.rpm
Preparing... ########################################### [100%]
1:varnish-docs ########################################### [100%]
[[email protected] RPMvarnish]# rpm -ivh varnish-libs-3.0.4-1.el6.x86_64.rpm
Preparing... ########################################### [100%]
1:varnish-libs ########################################### [100%]
[[email protected] RPMvarnish]# rpm -ivh varnish-libs-devel-3.0.4-1.el6.x86_64.rpm
Preparing... ########################################### [100%]
1:varnish-libs-devel ########################################### [100%]
[[email protected] RPMvarnish]#varnish-agent-1.16-0.el6.x86_64.rpm
Preparing... ########################################### [100%]
1:varnish-libs-devel ########################################### [100%]
如果支援連接配接到網絡的話建議用如下方式安裝：
For RHEL 6 and compatible distributions, use
rpm --nosignature -i http://repo.varnish-cache.org/redhat/varnish-3.0/el6/noarch/varnish-release-3.0-1.el6.noarch.rpm
and then run
yum install varnish
The
--no-signature
is only needed on initial installation, since the Varnish GPG key is not yet in the yum keyring
下邊進行varnish的啟動介紹和簡單的配置：
簡單的配置varnish：
[[email protected] varnish-3.0.3]# cat /etc/varnish/default.vcl
backend webserver {
.host = "127.0.0.1"; //後端伺服器的IP位址或者完全的FQDN名或者hostname
.port = "8000"; //後端伺服器提供服務的端口
}
sub vcl_recv {
if (!req.http.x-forwarded-for) {
set req.http.X-Forwarded-For = client.ip;
}
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.url ~ "\.(jsp|do)($|\?)") {
return (pass);
}
else {
return (lookup);
}
}
sub vcl_pipe {
return (pipe);
}
sub vcl_pass {
return (pass);
}
sub vcl_hash {
hash_data(req.url);
if (req.http.host) {
hash_data(req.http.host);
} else {
hash_data(server.ip);
}
return (hash);
}
sub vcl_hit {
return (deliver);
}
sub vcl_miss {
return (fetch);
}
sub vcl_fetch {
if (beresp.ttl <= 0s ||
beresp.http.Set-Cookie ||
beresp.http.Vary == "*") {
set beresp.ttl = 120 s;
return (hit_for_pass);
}
if (req.request == "GET" && req.url ~ "^/static(.*)$") {
set beresp.ttl = 600s;
}
if (req.request == "GET" && req.url ~ "\.(png|xsl|xml|pdf|ppt|doc|docx|chm|rar|zip|bmp|jpeg|swf|ico|mp3|mp4|rmvb|ogg|mov|avi|wmv|swf|txt|png|gif|jpg|css|js|html|htm)$") {
set beresp.ttl = 1800s;
}
return (deliver);
}
sub vcl_deliver {
if (obj.hits > 0) {
set resp.http.X-Cache = "HIT john.local";
}
else {
set resp.http.X-Cache = "MISS from john.local";
}
return (deliver);
}
****************************************
這是一個簡單的示例性配置檔案筆者
沒有作出詳細的注釋或者解釋，筆者
将會在後邊的博文中漸漸解釋VCL也
就是varnish的配置檔案的寫法
****************************************
啟動varnish服務：
[[email protected] varnish-3.0.3]# /usr/local/varnish/sbin/varnishd -f /etc/varnish/default.vcl -s malloc,1G -T 127.0.0.1:2000 -a 0.0.0.0:80
參數說明：
f: 需要加載的vcl檔案
s:用malloc函數動态排程記憶體，為1G
T:管理端口和監聽位址
a:服務的監聽端口，對外提同服務
簡單的測試：
[[email protected] varnish-3.0.3]# lsof -i:80
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
varnishd 13467 nobody 6u IPv4 25286 0t0 TCP *:http (LISTEN)
[[email protected] varnish-3.0.3]# curl -I http://192.168.0.111
HTTP/1.1 200 OK
Server: Apache/2.2.15 (Red Hat)
Last-Modified: Sun, 11 Aug 2013 11:57:24 GMT
ETag: "248c-1b-4e3aab609ddb4"
Content-Type: text/html; charset=UTF-8
Content-Length: 27
Accept-Ranges: bytes
Date: Sat, 31 Aug 2013 15:00:45 GMT
X-Varnish: 2074431089 2074431086
Age: 48
Via: 1.1 varnish
Connection: keep-alive
X-Cache: HIT john.local //HIT為命中緩存
[[email protected] ~]# curl -I http://192.168.0.111
HTTP/1.1 200 OK
Server: Apache/2.2.15 (Red Hat)
Last-Modified: Sun, 11 Aug 2013 11:57:24 GMT
ETag: "248c-1b-4e3aab609ddb4"
Content-Type: text/html; charset=UTF-8
Content-Length: 27
Accept-Ranges: bytes
Date: Sat, 31 Aug 2013 15:02:43 GMT
X-Varnish: 2074431090
Age: 0
Via: 1.1 varnish
Connection: keep-alive
X-Cache: MISS from john.local //MISS為未命中
VCL寫法将會在下篇博文中詳細剖析
VCL詳解 請移步至：
http://blog.csdn.net/cwg_1992/article/details/10742625
########################################
本文有筆者原創
作者：john
轉載請注明出處
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