Varnish配置，Error 503解决之道

首先，说说Varnish的配置方法。 Varnish的启动需要配置文件（*.vcl）,以及其他一些启动参数配合（具体参数在此略去不谈，man一下会看到一切）。我安装的是Varnish-2.0.4 整个安装过程如下： #./configure –prefix=/usr/local/varnish –enable-developer-waring –enable-debugging-sybmbles –enable-werror #make #make install 编译安装完成，然后就需要启动它，我写的启动文件如下： ###Start.sh###### #!/bin/sh #file:start.sh date -u /usr/local/varnish/sbin/varnishd -a 173.26.100.206:80 -s file,/cache/varnish/V,1024m -f /usr/local/varnish/etc/varnish/default.vcl -p thread_pool_max=1500 -p thread_pools=5 -p listen_depth=512 -p client_http11=on -p connect_timeout = 1s -p send_timeout = 20s 以下是deault.vcl配置 ######defualt.vcl######## backend default { .host = “173.26.100.206″; .port = “81″; } #Below is a commented-out copy of the default VCL logic. If you #redefine any of these subroutines, the built-in logic will be #appended to your code. sub vcl_recv { if (req.request != “GET” && req.request != “HEAD” && req.request != “PUT” && req.request != “POST” && req.request != “TRACE” && req.request != “OPTIONS” && req.request != “DELETE”) { /* Non-RFC2616 or CONNECT which is weird. */ return (pipe); } if (req.request != “GET” && req.request != “HEAD”) { /* We only deal with GET and HEAD by default */ return (pass); } if (req.http.Authorization || req.http.Cookie) { /* Not cacheable by default */ return (pass); } return (lookup); } sub vcl_pipe { # Note that only the first request to the backend will have # X-Forwarded-For set. If you use X-Forwarded-For and want to # have it set for all requests, make sure to have: # set req.http.connection = “close”; # here. It is not set by default as it might break some broken web # applications, like IIS with NTLM authentication. 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 (!obj.cacheable) { return (pass); } return (deliver); } sub vcl_miss { return (fetch); } sub vcl_fetch { if (!obj.cacheable) { return (pass); } if (obj.http.Set-Cookie) { return (pass); } set obj.prefetch = -30s; return (deliver); } sub vcl_deliver { return (deliver); } sub vcl_discard { /* XXX: Do not redefine vcl_discard{}, it is not yet supported */ return (discard); } sub vcl_prefetch { /* XXX: Do not redefine vcl_prefetch{}, it is not yet supported */ return (fetch); } sub vcl_timeout { /* XXX: Do not redefine vcl_timeout{}, it is not yet supported */ return (discard); } sub vcl_error { set obj.http.Content-Type = “text/html; charset=utf-8″; synthetic {” "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> Error “} obj.status ” ” obj.response {” “} obj.response {” Guru Meditation: XID: “} req.xid {” Varnish “}; return (deliver); } 如此配置，运行./Start.sh启动Varnish监听本机80端口，backend为Apache监听的81端口。问题出现了，通过81端口访问，正常响应，浏览器获得正确页面；访问81端口，出现503 error。 对于这个问题在网上搜了很多方法试图解决，比较多的办法是在配置文件里修改添加 backend default { .host = “173.26.100.206″; .port = “81″; ###下面三行为新加配置 .connect_timeout = 1s; .first_byte_timeout = 5s; .between_bytes_timeout = 2s; } 事实上并不奏效，自己摸索良久，偶然将start.sh中一些启动选项去掉，结果发现可以正常响应了。 新的启动文件如下： ####Start.sh##### #!/bin/sh #file:start.sh date -u /usr/local/varnish/sbin/varnishd -a 173.26.100.206:80 -s file,/cache/varnish/V,1024m -f /usr/local/varnish/etc/varnish/default.vcl -p thread_pool_max=1500 -p thread_pools=5 -p listen_depth=512 -p client_http11=on 去掉了connect_timeout和send_timeout，相当于使用系统默认配置。 结果一切归于正常，Varnish又一次表现出高速的http代理能力。