#
# Customized VCL file for serving up a Drupal site with multiple back-ends.
#
# For more information on this VCL, visit the Lullabot article:
# http://www.lullabot.com/articles/varnish-multiple-web-servers-drupal
#
# 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 = "192.10.0.1"; .probe = { .url = "/status.php"; .interval = 5s; .timeout = 1s; .window = 5;.threshold = 3; }}
backend web2 { .host = "192.10.0.2"; .probe = { .url = "/status.php"; .interval = 5s; .timeout = 1s; .window = 5;.threshold = 3; }}
# Port 443 Backend Servers for SSL
backend web1_ssl { .host = "192.10.0.1"; .port = "443"; .probe = { .url = "/status.php"; .interval = 5s; .timeout = 1 s; .window = 5;.threshold = 3; }}
backend web2_ssl { .host = "192.10.0.2"; .port = "443"; .probe = { .url = "/status.php"; .interval = 5s; .timeout = 1 s; .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 {
# 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 {"
Page Unavailable
Page Unavailable
The page you requested is temporarily unavailable.
We're redirecting you to the homepage in 5 seconds.