varnish 503 的配置（需改进）

# This is a basic VCL configuration file for varnish.  See the vcl(7)# man page for details on VCL syntax and semantics.# # Default backend definition.  Set this to point to your content# server.#  #webserver1_13 backend webserver1 {    .host = "192.168.0.13";    .port = "12113";    .probe = {.url = "/index.html";        .interval = 10s;        .timeout = 10s;.window = 5;        .threshold = 4;    }    .connect_timeout = 600s;    .first_byte_timeout = 600s;    .between_bytes_timeout = 600s; } #webserver2_14 backend webserver2 {    .host = "192.168.0.14";    .port = "12113";    .probe = {        .url = "/index.html";        .interval = 10s;        .timeout = 10s;        .window = 5;        .threshold = 4;    }    .connect_timeout = 600s;    .first_byte_timeout = 600s;    .between_bytes_timeout = 600s; } #webserver_13_14 director webserver round-robin {{.backend = webserver1;#.weight = 5;}{.backend = webserver2;#.weight = 5;} } #allow clean cache control acl purge {        "localhost";        "127.0.0.1";        "192.168.7.10"; }# # 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.http.host ~ "(.*)xxxx.xxx.com") { set req.http.host = "xxxx.xxx.com";      }#      if ((req.http.host ~ "^xxxx.xxx.com") && (req.restarts == 0)) {         set req.backend = webserver;#      }#      elseif (req.restarts == 1) {#         set req.backend = webserver2;#      }     if (req.request == "PURGE") {if (!client.ip ~ purge) {error 405 "Not allowed.";        }return (lookup);     }     #real IP     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; }     }     #gzip,need zlib-devel     if (req.http.Accept-Encoding) {if (req.http.Accept-Encoding ~ "gzip") {set req.http.Accept-Encoding = "gzip";}elseif (req.http.Accept-Encoding ~ "deflate") {set req.http.Accept-Encoding = "deflate";}else {remove req.http.Accept-Encoding;}     }     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);      }      if (req.request == "GET" && req.url ~ "\.(jpg|png|gif|swf|jpeg|m3u8|mp4|flv|ts)$") {unset req.http.cookie;      }            return (lookup); }  sub vcl_pipe {     # Note that only the first request to the backend will have     # X-Forwarded-For set.  If you use X-Forwarded-For and want to     # have it set for all requests, make sure to have:     # set bereq.http.connection = "close";     # here.  It is not set by default as it might break some broken web     # applications, like IIS with NTLM authentication.     return (pipe); }  sub vcl_pass {     return (pass); }#  sub vcl_hash {     hash_data(req.url);     if (req.http.host) {         hash_data(req.http.host);     } else {         hash_data(server.ip);     }     return (hash); }#  sub vcl_hit {     if (req.request == "PURGE") {set obj.ttl = 0s;error 200 "Purged.";     }     return (deliver); }#  sub vcl_miss {     if (req.request == "PURGE") {error 404 "Not in cache.";     }set req.http.host = "miss";     return (fetch); }#  sub vcl_fetch {      #Define what state into the restart model      if (beresp.status == 500 || beresp.status == 501 || beresp.status == 502 || beresp.status == 503 || beresp.status == 504) {set req.http.host = "status";set beresp.saintmode = 10s;return (restart);      }       #The definition does not contain the cache HTTP header request      if (beresp.http.Pragma ~ "no-cache" || beresp.http.Cache-Control ~ "no-cache" || beresp.http.Cache-Control ~ "private") {return (hit_for_pass);     }      #Define different content cache time      if (req.request == "GET" && req.url ~ "\.(css|js|html|htm)$") {set beresp.ttl = 7d;      }      if (req.request == "GET" && req.url ~ "\.(gif|jpg|jpeg|bmp|tiff|tif|ico|img|bmp|wmf)$") {set beresp.ttl = 10d;      }      if (!req.backend.healthy) {set req.grace = 1m;      }      else {set req.grace = 30s;      }      if (beresp.ttl <= 0s ||         beresp.http.Set-Cookie ||         beresp.http.Vary == "*") { /*  * Mark as "Hit-For-Pass" for the next 2 minutes  */ set beresp.ttl = 120 s; return (hit_for_pass);      }      return (deliver); }#  sub vcl_deliver {     #set resp.http.x-hits = obj.hits;set resp.http.x-hits = req.restarts;set resp.http.x-hits = req.http.host;     if (obj.hits > 0) {set resp.http.X-Cache = "HIT";     }     else {set resp.http.X-Cache = "MISS";     }     return (deliver); }#  sub vcl_error {     set obj.http.Content-Type = "text/html; charset=utf-8";     set obj.http.Retry-After = "5";     synthetic {" <?xml version="1.0" encoding="utf-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html>   <head>     <title>"} + obj.status + " " + obj.response + {"</title>   </head>   <body>     <h1>Error "} + obj.status + " " + obj.response + {"</h1>     <p>"} + obj.response + {"</p>     <h3>Guru Meditation:</h3>     <p>XID: "} + req.xid + {"</p>     <hr>     <p>Varnish cache server</p>   </body> </html> "};     return (deliver); }# # sub vcl_init {# return (ok);# }# # sub vcl_fini {# return (ok);# }