Cache updating not working for me

[nick tailor]

Sweet. One more question.

Currently. I'm testing my varnish environment, everything seems to be
working fine except one thing. I would like my cache to update every 30
seconds if the backend is healthy and serve stale content if the backend
goes down.

The content is served perfectly when the backend is down, however the cache
is not updating every 30 seconds if the backend is healthy. Could someone
have a look at my config below and tell me what I'm missing?

Please and thank you

=====================================
# Define the internal network subnet.
# These are used below to allow internal access to certain files while not
# allowing access from the public internet.
acl internal {
  "192.10.0.0"/24;
}

# Define the list of backends (web servers).
# Port 80 Backend Servers
backend web1 { .host = "testing.com"; .probe = { .url = "/"; .interval =
5s; .timeout = 1s; .window = 5;.threshold = 3; }}
backend web2 { .host = "testing.com"; .probe = { .url = "/"; .interval =
5s; .timeout = 1s; .window = 5;.threshold = 3; }}

# Port 443 Backend Servers for SSL
backend web1_ssl { .host = "testing.com"; .port = "443"; .probe = { .url =
"/"; .interval = 5s; .timeout = 5s; .window = 5;.threshold = 3; }}
backend web2_ssl { .host = "testing.com"; .port = "443"; .probe = { .url =
"/"; .interval = 5s; .timeout = 5s; .window = 5;.threshold = 3; }}

# Define the director that determines how to distribute incoming requests.
director default_director round-robin {
  { .backend = web1; }
  { .backend = web2; }
}

director ssl_director round-robin {
  { .backend = web1_ssl; }
  { .backend = web2_ssl; }
}

# Respond to incoming requests.
sub vcl_recv {
  # Allow the backend to serve up stale content if it is responding slowly.
 if (req.backend.healthy) {

        set req.grace = 30s;

 } else {
                set req.grace = 5h;
        }
}


# Code determining what to do when serving items from the Apache servers.
sub vcl_fetch {
  # Allow items to be stale if needed.
  set beresp.grace = 6h;
  set beresp.ttl = 12h;
}

# Respond to incoming requests.
sub vcl_recv {
  # Set the director to cycle between web servers.
  if (server.port == 443) {
    set req.backend = ssl_director;
  }
  else {
   set req.backend = default_director;
  }

  # 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;

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

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

  # 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";
  }

  # Handle compression correctly. Different browsers send different
  # "Accept-Encoding" headers, even though they mostly all support the same
  # compression mechanisms. By consolidating these compression headers into
  # a consistent format, we can reduce the size of the cache and get more
hits.=
  # @see: http:// varnish.projects.linpro.no/wiki/FAQ/Compression
  if (req.http.Accept-Encoding) {
    if (req.http.Accept-Encoding ~ "gzip") {
      # If the browser supports it, we'll use gzip.
      set req.http.Accept-Encoding = "gzip";
    }
    else if (req.http.Accept-Encoding ~ "deflate") {
      # Next, try deflate if it is supported.
      set req.http.Accept-Encoding = "deflate";
    }
    else {
      # Unknown algorithm. Remove it and send unencoded.
      unset req.http.Accept-Encoding;
    }
  }

  # Always cache the following file types for all users.
  if (req.url ~
"(?i)\.(png|gif|jpeg|jpg|ico|swf|css|js|html|htm)(\?[a-z0-9]+)?$") {
    unset req.http.Cookie;
  }

  # Remove all cookies that Drupal doesn't need to know about. ANY remaining
  # cookie will cause the request to pass-through to Apache. For the most
part
  # we always set the NO_CACHE cookie after any POST request, disabling the
  # Varnish cache temporarily. The session cookie allows all authenticated
users
  # to pass through as long as they're logged in.
  if (req.http.Cookie) {
    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]+|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);
    }
  }
}

# Routine used to determine the cache key if storing/retrieving a cached
page.
sub vcl_hash {
  # Include cookie in cache hash.
  # This check is unnecessary because we already pass on all cookies.
  # if (req.http.Cookie) {
  #   set req.hash += req.http.Cookie;
  # }
}

# Code determining what to do when serving items from the Apache servers.
sub vcl_fetch {
  # Don't allow static files to set cookies.
  if (req.url ~
"(?i)\.(png|gif|jpeg|jpg|ico|swf|css|js|html|htm)(\?[a-z0-9]+)?$") {
    # beresp == Back-end response from the web server.
    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);
}
===================================

Cheers

Nick Tailor
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