什么是varnish缓存代理？如何安装和配置？

varnish缓存代理

varnish 缓存是 web 应用加速器，同时也作为 http 反向缓存代理。你可以安装 varnish 在任何 http 的前端，同时配置它缓存内容。与传统的 squid 相比，varnish 具有性能更高、速度更 快、管理更加方便等诸多优点。

varnish 完整配置实例 1、拓扑环境 Varnish:192.168.31.250 Web01:192.168.31.83 Web02:192.168.31.141 配置 web01、web02 做为后端服务器（过程略） 确保 varnish 服务器能正常访问 web01、web02 Varnish 缓存代理服务器配置：

安装 varnish
1、安装依赖关系的软件包（注：使用 centos 在线 yum 源）

[root@varnish ~]# yum -y install autoconf automake libedit-devel libtool ncurses-devel pcre-devel   pkgconfig python-docutils python-sphinx

2、安装 varnish
Varnish 的官方网址为 http://varnish-cache.org，可以在这里下载最新版本的软件。
下载地址：https://www.varnish-cache.org/content/varnish-cache-403
注意：Varnish 网站有时会被墙。
Git 下载：git clone https://github.com/varnish/Varnish-Cache /var/tmp/
解压，进入解压目录编译安装：

[root@varnish ~]# tar zxf varnish-4.0.3.tar.gz [root@varnish ~]# cd varnish-4.0.3/ [root@varnish varnish-4.0.3]# export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig

注：
./autogen.sh
如果从 Git 库下载的安装包时才需要运行，用于生成 configure 编译文件。
配置：

[root@varnish varnish-4.0.3]# ./configure

注：不指定安装路径，默认是安装在/usr/local 目录下
编译、安装

[root@varnish varnish-4.0.3]# make && make install

复制 vcl 文件（在编译安装目录下），如果安装目录里没有 default.vcl 文件。
复制到安装目录的/usr/local/var/varnish/目录下（当然并无必需要求在哪个目录，因为正式
启动时还得指定这个文件的目录）
[root@varnish varnish-4.0.3]# cp etc/example.vcl /usr/local/var/varnish/default.vcl

配置default.vcl

[root@varnish varnish-4.0.3]#  vim /usr/loacl/var/varnish/default.vcl vcl 4.0; import directors; import std; probe backend_healthcheck {    .url="/";    .interval = 5s;    .timeout = 1s;    .window = 5;    .threshold = 3; } backend web_app_01 {    .host = "192.168.164.10";   #要改    .port = "80";    .first_byte_timeout = 9s;    .connect_timeout = 3s;    .between_bytes_timeout = 1s;    .probe = backend_healthcheck; } backend web_app_02 {    .host = "192.168.164.20";  #要改    .port = "80";    .first_byte_timeout = 9s;    .connect_timeout = 3s;    .between_bytes_timeout = 1s;    .probe = backend_healthcheck; } acl purgers {    "127.0.0.1";    "localhost";    "192.168.164.0/24";           #添加网段 } sub vcl_init {    new web = directors.round_robin();    web.add_backend(web_app_01);    web.add_backend(web_app_02); } sub vcl_recv { set req.backend_hint = web.backend(); if (req.method == "PURGE") {    if (!client.ip ~ purgers) {    return (synth(405, "Not Allowed.")); } return (purge); } if (req.method != "GET" &&req.method != "HEAD" && req.method != "PUT" && req.method != "POST" && req.method != "TRACE" && req.method != "OPTIONS" && req.method != "PATCH" && req.method != "DELETE") { return (pipe); } if (req.method != "GET" && req.method != "HEAD") { return (pass); } if (req.url ~ "\.(php|asp|aspx|jsp|do|ashx|shtml)($|\?)") { return (pass); } if (req.http.Authorization) { return (pass); } if (req.http.Accept-Encoding) { if (req.url ~"\.(bmp|png|gif|jpg|jpeg|ico|gz|tgz|bz2|tbz|zip|rar|mp3|mp4|ogg|swf|flv)$") { unset req.http.Accept-Encoding; } elseif (req.http.Accept-Encoding ~ "gzip") { set req.http.Accept-Encoding = "gzip"; } elseif (req.http.Accept-Encoding ~ "deflate") { set req.http.Accept-Encoding = "deflate"; } else { unset req.http.Accept-Encoding; } } if (req.url ~"\.(css|js|html|htm|bmp|png|gif|jpg|jpeg|ico|gz|tgz|bz2|tbz|zip|rar|mp3|mp4|ogg|swf|flv)($|\?)") { unset req.http.cookie; return (hash); } if (req.restarts == 0) { if (req.http.X-Forwarded-For) { set req.http.X-Forwarded-For = req.http.X-Forwarded-For + ", " + client.ip; } else { set req.http.X-Forwarded-For = client.ip; } } return (hash); } sub vcl_hash { hash_data(req.url); if (req.http.host) { hash_data(req.http.host); } else { hash_data(server.ip); } return (lookup); } sub vcl_hit {    if (req.method == "PURGE") {    return (synth(200, "Purged."));    }    return (deliver); } sub vcl_miss { if (req.method == "PURGE") { return (synth(404, "Purged.")); } return (fetch); } sub vcl_deliver { if (obj.hits > 0) { set resp.http.X-Cache = "HIT"; set resp.http.X-Cache-Hits = obj.hits; } else { set resp.http.X-Cache = "MISS"; } unset resp.http.X-Powered-By; unset resp.http.Server; unset resp.http.X-Drupal-Cache; unset resp.http.Via; unset resp.http.Link; unset resp.http.X-Varnish; set resp.http.xx_restarts_count = req.restarts; set resp.http.xx_Age = resp.http.Age; set resp.http.hit_count = obj.hits; unset resp.http.Age; return (deliver); } sub vcl_pass { return (fetch); } sub vcl_backend_response { set beresp.grace = 5m; if (beresp.status == 499 || beresp.status == 404 || beresp.status == 502) { set beresp.uncacheable = true; } if (bereq.url ~ "\.(php|jsp)(\?|$)") { set beresp.uncacheable = true; } else { if (bereq.url ~ "\.(css|js|html|htm|bmp|png|gif|jpg|jpeg|ico)($|\?)") { set beresp.ttl = 15m; unset beresp.http.Set-Cookie; } elseif (bereq.url ~ "\.(gz|tgz|bz2|tbz|zip|rar|mp3|mp4|ogg|swf|flv)($|\?)") { set beresp.ttl = 30m; unset beresp.http.Set-Cookie; } else { set beresp.ttl = 10m; unset beresp.http.Set-Cookie; } } return (deliver); } sub vcl_purge { return (synth(200,"success")); } sub vcl_backend_error { if (beresp.status == 500 || beresp.status == 501 || beresp.status == 502 || beresp.status == 503 || beresp.status == 504) { return (retry); } } sub vcl_fini { return (ok); }

**启动 varnish** [root@varnish ~]# /usr/local/sbin/varnishd -f /usr/local/var/varnish/default.vcl -s malloc,200M -a 0.0.0.0:80 [root@varnish ~]# netstat -anpt | grep 80