Varnish跟Squid都是一款内容加速缓存服务器，我们可以使用它们来对我们的网页内容进行缓存，以此来从某个方面提高用户体验度，提升网站整体的抗压能力。
目前自建的CDN中，有很多都是基于Squid、Varnish等相关缓存软件，经过内部的二次开发实现了更好的内容加速及管理。
那今天我们一起来学习一下Varnish简单的搭建及日常的维护，深入的东西后期分享，跟大家一起来交流。这里直接上Shell脚本自动初始化并安装：
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#!/bin/sh#auto install varnish#2014-07-28 by wugkDIR=/usr/src
CODE=$?VER=$1if [ -z $1 ];then
echo "Usage:{$0 'Version' install |config |start|help } , Example $0 2.1.5 install}"
exit
fiURL=https://repo.varnish-cache.org/source/varnish-${VER}.tar.gz
function install()
{if [ ! -d /usr/local/varnish -o ! -f /etc/init.d/varnishd ];then
cd $DIR ;wget -c $URL
if [ $CODE == '0' ];then
echo "This varnish Files is Download Successed!"
else
echo "This varnish Files is Download Failed!"
fi
useradd -s /sbin/noin varnish
mkdir -p /data/varnish/{cache,}
chown -R varnish.varnish /data/varnish/
tar xzf varnish-${VER}.tar.gz ;cd varnish-${VER} ;/bin/sh autogen.sh ;./configure --prefix=/usr/local/varnish --enable-dependency-tracking --enable-debugging-symbols --enable-developer-warnings -enable-extra-warnings &&make &&make install else echo "This Varnish is exists,Please exit..."
sleep 1
exit 0
fi}function config()
{ if [ ! -d /usr/local/varnish/ -o -f /etc/init.d/varnishd ];then
echo "You can't config varnish ,Please ensure you varnish dir is or not exist..."
exit 0
else
echo "Varnish Already Success Install ,Please Config varnish ......"
fi
mv /usr/local/varnish/etc/varnish/default.vcl /usr/local/varnish/etc/varnish/default.vcl.bak
cat >>/usr/local/varnish/etc/varnish/default.vcl <<EOF
backend server_1{.host ="192.168.149.128";
.port = "8080";
.probe = {.timeout = 5s;.interval = 2s;.window = 8;.threshold = 5;}}backend server_2{.host ="192.168.149.129";
.port = "8080";
.probe = {.timeout = 5s; .interval = 2s; .window = 8; .threshold = 5;}}director rsver random {{.backend = server_1;.weight = 6;}{.backend = server_2;.weight = 6;}}acl purge {"localhost";
"127.0.0.1";
}sub vcl_recv{ if (req.http.host ~"^(.*).tdt.com")
{
set req.backend =rsver;
}
else
{
error 200 "Nocahce for this domain";
}
if (req.request =="PURGE")
{
if (!client.ip ~purge)
{
error 405"Not allowed.";
}
else
{
return (pipe);
}
}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 !="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);
}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 TDTWS Cache Center";
} else {
set resp.http.X-Cache= "MISS FROM TDTWS Cache Center";
}
return (deliver);
}EOFif [ $? == 0 ];then
echo '----------------------------------'
sleep 2
echo "This Varinsh Config Success !!!"
else echo "This Varinsh Config Failed,Please Check Conf!"
fi}function start()
{if [ ! -d /usr/local/varnish -o -f /etc/init.d/varnishd ];then
echo "You can't config varnish ,Please ensure you varnish dir is or not exist..."
exit 0
else count=`ps -ef |grep varnishd|grep -v grep |wc -l`
if [ $count -eq 0 ];then
echo "Varnish Already Success Install ,Now start varnish...."
cat <<EOF
------------------------------------------------------
Start Varnish to listen 0.0.0.0:80.
The Varnish load balancer server1(192.168.149.128 8080).
The Varnish load balancer server1(192.168.149.129 8080).
The Varnish Mgr address to listen 0.0.0.0:8001.
The Varnish Cache DIR /data/varnish/cache .
EOF /usr/local/varnish/sbin/varnishd -n /data/varnish/cache -f /usr/local/varnish/etc/varnish/default.vcl -a 0.0.0.0:80 -s file,/data/varnish/varnish_cache.data,16G -p user=varnish -p group=varnish -p default_ttl=14400 -p thread_pool_max=8000 -p send_timeout=20 -w 5,51200,30 -T 0.0.0.0:8001 -P /usr/local/varnish/var/varnish.pid
if [ $? == 0 ];then
echo "Start varnish ...OK"
fi
else
echo "Warning,This Varnish Service is exist."
fi
fi}case $2 in
install)
install
;;
config)
config
;;
start )
start
;;
* )
echo "Usage:{ Usage $0 version install |config |start|help }"
;;
esac |
Varnish简单测试如下图：
1.第一张图，第一次访问没有命中，去后端服务器取数据，同时在本地缓存一份：（MISS）
2.第二张图，第二次访问，缓存服务器存在，则直接从缓存中返回：（HIT）
实际线上环境中，如果用户访问我们的网站，使用Ctrl+F5刷新，我们的缓存就会失效，因为我们配置文件里面是这么配置的，匹配浏览器头信息：
Pragma no-cache
Cache-Control no-cache
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if (req.http.Cache-Control~ "no-cache")
{return (pass);
} |
只有注释掉这段代码或者设置只允许某个特定的IP，用户通过浏览器按Crtl+F5才不会把缓存给清除。
下面是针对某个特定的IP地址允许刷新：
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acl local {
"192.168.149.128"
}sub vcl_hit { if (!obj.cacheable) {
return (pass);
}
if (client.ip ~ local && req.http.Pragma ~ "no-cache") {
set obj.ttl = 0s;
return (pass);
}
return (deliver);
} |
由于时间的原因，文章就暂时写到这里，更多深入的东西继续分享，文章引用煮酒哥的配置，非常感谢。欢迎大家一起讨论。
http://yuhongchun.blog.51cto.com/1604432/1293169
本文转自 wgkgood 51CTO博客，原文链接:http://blog.51cto.com/wgkgood/1531694