CentOS 5.8 下如何安裝配置 Varnish-2.1.5 ？
原創(chuàng)【51CTO原創(chuàng)稿件】Varnish是一款強(qiáng)大的反向代理加速軟件，關(guān)于其工作原理可以參考下圖，其具體流程及VCL語法我這里就不做說明，網(wǎng)上資料多，大家還可以對(duì)照參考其官方網(wǎng)站和《Varnish中文權(quán)威指南》：
一、安裝CentOS5.8系統(tǒng)環(huán)境下的依耐關(guān)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，并進(jìn)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(guān)系是否滿足，如果報(bào)錯(cuò)的話， 則應(yīng)該如下正常所示：
- + aclocal
- + libtoolize --copy --force
- + autoheader
- + automake --add-missing --copy --foreign
- + autoconf
繼續(xù)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(chuàng)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(huán)境是兩臺(tái)Web機(jī)器，IP為192.168.1.103（域名為http://www.yuhongchun027.net）的varnish機(jī)器對(duì)后端IP為192.168.1.104和192.168.1.105的機(jī)器進(jìn)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(shí)間超時(shí)
- .interval = 2s; #檢查時(shí)間間隔
- .window = 10; #varnish將維持10個(gè)sliding windows的結(jié)果
- .threshold = 8; #如果是8次.windows檢查是成功的，就宣告后端的Web機(jī)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(gè)名為realserver組，使用random機(jī)制，權(quán)重越大，分配的訪問越多，可根據(jù)服務(wù)器性能來設(shè)定；而round-robin（輪詢）機(jī)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(jī)器，這里只允許本機(jī)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(shí)IP地址
- if(req.http.x-forwarded-for)
- {
- set reqreq.http.X-Forwarded-For =
- req.http.X-Forwarded-For "," client.ip;
- }
- else
- {
- set req.http.X-Forwarded-For =client.ip;
- }
#對(duì)HTTP協(xié)議中的GET、HEAD請求進(jìn)行緩存，對(duì)POST請求透過，讓其直接訪問后端Web服務(wù)器。之所以這樣配置，是因?yàn)镻OST請求一般是發(fā)送數(shù)據(jù)給服務(wù)器的，需要服務(wù)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(duì)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)$")
- {
- set beresp.ttl = 3600s;
- }
- else
- {
- set beresp.ttl = 30d;
- }
- if (!beresp.cacheable)
- {
- return (pass);
- }
- if (beresp.http.Set-Cookie)
- {
- return (pass);
- }
- return (deliver);
- }
- sub vcl_deliver {
- if (obj.hits > 0) {
- set resp.http.X-Cache= "HIT FROM www.yuhongchun027.net";
- } else {
- set resp.http.X-Cache= "MISS FROM www.yuhongchun027.net";
- }
- return (deliver);
- }
五、啟動(dòng)varnish的命令很長，如下所示：
| /usr/local/varnish/sbin/varnishd -n /data/varnish/cache -f /usr/local/varnish/etc/varnish/better.vcl -a 0.0.0.0:80 -s file,/data/varnish/varnish_cache.data,8G -p user=varnish -p group=varnish -p default_ttl=14400 -p thread_pool_max=8000 -p send_timeout=20 -w 5,51200,30 -T 127.0.0.1:3500 -p /usr/local/varnish/var/varnish.pid |
驗(yàn)證其是否生效可以用curl -I命令，如下所示：
- [root@localhost cache]# curl -I http://www.yuhongchun027.net/
- HTTP/1.1 200 OK
- Server: Apache/2.2.3 (CentOS)
- Last-Modified: Wed, 28 Aug 2013 16:27:33 GMT
- ETag: "10d242-e-776b6740"
- Content-Type: text/html; charset=UTF-8
- Content-Length: 14
- Date: Wed, 21 Aug 2013 17:47:48 GMT
- X-Varnish: 1584727079 1584726982
- Age: 10101
- Via: 1.1 varnish
- Connection: keep-alive
- X-Cache: HIT FROM www.yuhongchun027.net
六、如果vcl配置文件發(fā)生改動(dòng)，想要不重啟而直接reload，可以用如下操作，可以在本機(jī)上進(jìn)行telnet操作，連接3500管理端口：
- telnet 127.0.0.1 3500
- vcl.load newconfig /usr/local/varnish/etc/varnish/better.vcl
- 200 13
- VCL compiled.
- vcl.use newconfig
- 200 0
如果顯示有200字樣，則表示已經(jīng)正常reload了，newconfig這個(gè)名字是自己定義的，熟悉varnish操作的朋友應(yīng)該也清楚，通過telnet連接本機(jī)還可以進(jìn)行清理緩存。
七、用varnishadm命令來清理緩存，例子如下所示：
清除所有緩存：
- /usr/local/varnish/bin/varnishadm -T 192.168.1.103:3500 url.purge *$
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(xì)url列表，可執(zhí)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(yùn)行狀態(tài)和效果，如果緩存率命中率過低，我們應(yīng)該對(duì)varnish配置進(jìn)行檢查調(diào)整來進(jìn)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(nèi)核優(yōu)化如下所示：
編輯/etc/sysctl.conf，添加如下選項(xiàng)：
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(zhí)行如下命令，讓改動(dòng)配置立即生效：
- /sbin/sysctl -p
注意：老生常談的ulimit的問題，這個(gè)話題說得太多了，這里實(shí)在不想再提了，記得將
- ulimit -SHn 65535
放在/etc/rc.local里即可，記得在啟動(dòng)varnish之前將此命令手動(dòng)執(zhí)行一遍，另外，在工作中發(fā)現(xiàn)，CentOS6.x x86_64下更改ulimit跟CentOS5.x x86_64略有不同，這點(diǎn)也請大家注意。
以上即為varnish-2.1.5在CentOS5.8下的安裝配置過程，記錄下作為工作筆記，年紀(jì)大了，起個(gè)備忘作用而矣。
個(gè)人博客：http://andrewyu.blog.51cto.com
微博地址：http://weibo.com/yuhongchun027
【聲明】本文作者：余洪春(撫琴煮酒)，英文名Andrew.Yu。在51CTO系統(tǒng)頻道首發(fā)，轉(zhuǎn)載請注明作者和出處。
