Apache-2.2

為什麼 Varnish 不記憶體？

  • October 13, 2012

我正在對我的 Ubuntu 伺服器上的 Varnish 3.x 設置進行故障排除。我通過基於命名的虛擬主機在盒子上設置的兩個站點上執行 Drupal 7。在嘗試讓 Varnish 與 Drupal 一起玩之前，我試圖將 Varnish 從記憶體中轉換為 PNG。

這是我從curl -IPNG 文件的請求中獲得的標頭：

HTTP/1.1 200 OK
Server: Apache/2.2.22 (Ubuntu)
Last-Modified: Sun, 07 Oct 2012 21:18:59 GMT
ETag: "a57c2-3850-4cb7ea73db6c0"
Accept-Ranges: bytes
Content-Length: 14416
Cache-Control: max-age=1209600
Expires: Thu, 25 Oct 2012 22:55:14 GMT
Content-Type: image/png
Accept-Ranges: bytes
Date: Thu, 11 Oct 2012 22:55:14 GMT
X-Varnish: 1766703058
Age: 0
Via: 1.1 varnish
Connection: keep-alive
X-Varnish-Cache: MISS

以下是同一文件的標頭，但繞過了 Varnish（埠 8080）：

HTTP/1.1 200 OK
Date: Sat, 13 Oct 2012 13:16:17 GMT
Server: Apache/2.2.22 (Ubuntu)
Last-Modified: Sun, 07 Oct 2012 21:18:59 GMT
ETag: "a57c2-3850-4cb7ea73db6c0"
Accept-Ranges: bytes
Content-Length: 14416
Cache-Control: max-age=1209600
Expires: Sat, 27 Oct 2012 13:16:17 GMT
Content-Type: image/png

這是我正在使用的 Varnish VCL 文件（這是為 Drupal 設計的預設 VCL 配置）：

# Default backend definition.  Set this to point to your content
# server.
#
backend default {
 .host = "127.0.0.1";
 .port = "8080";
}

# Respond to incoming requests.
sub vcl_recv {
 # Use anonymous, cached pages if all backends are down.
 if (!req.backend.healthy) {
   unset req.http.Cookie;
 }

 # Allow the backend to serve up stale content if it is responding slowly.
 set req.grace = 6h;

 # Pipe these paths directly to Apache for streaming.
 #if (req.url ~ "^/admin/content/backup_migrate/export") {
 #  return (pipe);
 #}

 # Do not cache these paths.
 if (req.url ~ "^/status\.php$" ||
     req.url ~ "^/update\.php$" ||
     req.url ~ "^/admin$" ||
     req.url ~ "^/admin/.*$" ||
     req.url ~ "^/flag/.*$" ||
     req.url ~ "^.*/ajax/.*$" ||
     req.url ~ "^.*/ahah/.*$") {
      return (pass);
 }

 # Do not allow outside access to cron.php or install.php.
 #if (req.url ~ "^/(cron|install)\.php$" && !client.ip ~ internal) {
   # Have Varnish throw the error directly.
 #  error 404 "Page not found.";
   # Use a custom error page that you've defined in Drupal at the path "404".
   # set req.url = "/404";
 #}

 # Always cache the following file types for all users. This list of extensions
 # appears twice, once here and again in vcl_fetch so make sure you edit both
 # and keep them equal.
 if (req.url ~ "(?i)\.(pdf|asc|dat|txt|doc|xls|ppt|tgz|csv|png|gif|jpeg|jpg|ico|swf|css|js)(\?.*)?$") {
   unset req.http.Cookie;
 }

 # Remove all cookies that Drupal doesn't need to know about. We explicitly 
 # list the ones that Drupal does need, the SESS and NO_CACHE. If, after 
 # running this code we find that either of these two cookies remains, we 
 # will pass as the page cannot be cached.
 if (req.http.Cookie) {
   # 1. Append a semi-colon to the front of the cookie string.
   # 2. Remove all spaces that appear after semi-colons.
   # 3. Match the cookies we want to keep, adding the space we removed 
   #    previously back. (\1) is first matching group in the regsuball.
   # 4. Remove all other cookies, identifying them by the fact that they have
   #    no space after the preceding semi-colon.
   # 5. Remove all spaces and semi-colons from the beginning and end of the 
   #    cookie string. 
   set req.http.Cookie = ";" + req.http.Cookie;
   set req.http.Cookie = regsuball(req.http.Cookie, "; +", ";");    
   set req.http.Cookie = regsuball(req.http.Cookie, ";(SESS[a-z0-9]+|SSESS[a-z0-9]+|NO_CACHE)=", "; \1=");
   set req.http.Cookie = regsuball(req.http.Cookie, ";[^ ][^;]*", "");
   set req.http.Cookie = regsuball(req.http.Cookie, "^[; ]+|[; ]+$", "");

   if (req.http.Cookie == "") {
     # If there are no remaining cookies, remove the cookie header. If there
     # aren't any cookie headers, Varnish's default behavior will be to cache
     # the page.
     unset req.http.Cookie;
   }
   else {
     # If there is any cookies left (a session or NO_CACHE cookie), do not
     # cache the page. Pass it on to Apache directly.
     return (pass);
   }
 }
}

# Set a header to track a cache HIT/MISS.
sub vcl_deliver {
 if (obj.hits > 0) {
   set resp.http.X-Varnish-Cache = "HIT";
 }
 else {
   set resp.http.X-Varnish-Cache = "MISS";
 }
}

# Code determining what to do when serving items from the Apache servers.
# beresp == Back-end response from the web server.
sub vcl_fetch {
 # We need this to cache 404s, 301s, 500s. Otherwise, depending on backend but 
 # definitely in Drupal's case these responses are not cacheable by default.
 if (beresp.status == 404 || beresp.status == 301 || beresp.status == 500) {
   set beresp.ttl = 10m;
 }

 # Don't allow static files to set cookies. 
 # (?i) denotes case insensitive in PCRE (perl compatible regular expressions).
 # This list of extensions appears twice, once here and again in vcl_recv so 
 # make sure you edit both and keep them equal.
 if (req.url ~ "(?i)\.(pdf|asc|dat|txt|doc|xls|ppt|tgz|csv|png|gif|jpeg|jpg|ico|swf|css|js)(\?.*)?$") {
   unset beresp.http.set-cookie;
 }

 # Allow items to be stale if needed.
 set beresp.grace = 6h;
}

# In the event of an error, show friendlier messages.
sub vcl_error {
 # Redirect to some other URL in the case of a homepage failure.
 #if (req.url ~ "^/?$") {
 #  set obj.status = 302;
 #  set obj.http.Location = "http://backup.example.com/";
 #}

 # Otherwise redirect to the homepage, which will likely be in the cache.
 set obj.http.Content-Type = "text/html; charset=utf-8";
 synthetic {"
<html>
<head>
 <title>Page Unavailable</title>
 <style>
   body { background: #303030; text-align: center; color: white; }
   #page { border: 1px solid #CCC; width: 500px; margin: 100px auto 0; padding: 30px; background: #323232; }
   a, a:link, a:visited { color: #CCC; }
   .error { color: #222; }
 </style>
</head>
<body onload="setTimeout(function() { window.location = '/' }, 5000)">
 <div id="page">
   <h1 class="title">Page Unavailable</h1>
   <p>The page you requested is temporarily unavailable.</p>
   <p>We're redirecting you to the <a href="/">homepage</a> in 5 seconds.</p>
   <div class="error">(Error "} + obj.status + " " + obj.response + {")</div>
 </div>
</body>
</html>
"};
 return (deliver);
}

我每次都得到一個 MISS 和 0 歲。如果我理解正確，這意味著文件沒有從 Varnish 的記憶體中返回。我的 Varnish 配置有問題嗎？

更新：

正如建議的那樣，我從一個基本的 VCL 文件開始，但每次我仍然會失敗。VCL 配置為：

# Default backend definition.  Set this to point to your content
# server.
#
backend default {
 .host = "127.0.0.1";
 .port = "8080";
}

# Respond to incoming requests.
sub vcl_recv {
 unset req.http.Cookie;
}

# Set a header to track a cache HIT/MISS.
sub vcl_deliver {
 if (obj.hits > 0) {
   set resp.http.X-Varnish-Cache = "HIT";
 }
 else {
   set resp.http.X-Varnish-Cache = "MISS";
 }
}

# Code determining what to do when serving items from the Apache servers.
# beresp == Back-end response from the web server.
sub vcl_fetch {
 unset beresp.http.set-cookie;
}

我正在繼續排除故障。

好吧，它變成了超級簡單的東西，我不敢相信我錯過了：我在網站上使用了 Apache 基本授權，看起來 Varnish 預設情況下在看到授權標頭時返回一個通行證。

您需要在負責 drupal 虛擬主機的 httpd.conf 中包含以下行。

Header unset ETag

另外，我建議你去/使用：Varnish HTTP Accelerator Integration | drupal.org

引用自：https://serverfault.com/questions/437549

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