Varnish config for WordPress

~$ cat /etc/apt/sources.list.d/varnish.list
deb http://repo.varnish-cache.org/debian/ wheezy varnish-3.0
~$ apt-get update
~$ apt-get install varnish

backend default {
    .host = "127.0.0.1";
    .port = "8080";
}
 
# Who is allowed to purge?
acl purgers {
    "localhost";
    "88.151.240.193"; # Change this by the ip address(es) from where you would want to perform PURGE operations
}
 
sub vcl_recv {
 
    if (req.request == "PURGE") {
        if (!client.ip ~ purgers) {
	    error 405 "You are not allowed to purge";
	}
	    return(lookup);
    }
 
    # Set proxied ip header to original remote address
        set req.http.X-Forwarded-For = client.ip;
 
    # If the backend fails, keep serving out of the cache for 30m
        set req.grace = 30m;
 
    # Remove has_js and Google Analytics cookies
        set req.http.Cookie = regsuball(req.http.Cookie, "(^|;\s*)(__[a-z]+|__utm*|has_js)=[^;]*", "");
 
    # Remove a ";" prefix, if present.
    set req.http.Cookie = regsub(req.http.Cookie, "^;\s*", "");
 
    # Remove empty cookies.
    if (req.http.Cookie ~ "^\s*$") {
            unset req.http.Cookie;
    }
 
    # remove double // in urls,
        set req.url = regsuball( req.url, "//", "/"      );
 
    # Normalize Accept-Encoding
    if (req.http.Accept-Encoding) {
        if (req.url ~ "\.(jpg|png|gif|gz|tgz|bz2|tbz|mp3|ogg)$") {
            # No point in compressing these
            remove req.http.Accept-Encoding;
        } elsif (req.http.Accept-Encoding ~ "gzip") {
            set req.http.Accept-Encoding = "gzip";
        } elsif (req.http.Accept-Encoding ~ "deflate") {
            set req.http.Accept-Encoding = "deflate";
        } else {
            # unknown algorithm
            remove req.http.Accept-Encoding;
        }
    }
 
    # Remove cookies for static files
    if (req.url ~ "\.(gif|jpg|jpeg|swf|css|js|flv|mp3|mp4|pdf|ico|png|tif|tiff|mp3|htm|html)(\?.*|)$") {
        unset req.http.cookie;
        return(lookup);
    }
 
    # Disable caching for backend parts
    if ( req.url ~ "^/[^?]+/wp-(login|admin)" || req.url ~ "^/wp-(login|admin)" || req.url ~ "preview=true" ) {
        return(pass);
    }
 
    # always pass through posted requests and those with basic auth
    if ( req.request == "POST" || req.http.Authorization ) {
        return (pass);
    }
 
    # Strip cookies for cached content
    unset req.http.Cookie;
    return(lookup);
 
}
 
sub vcl_fetch {
 
    # If the backend fails, keep serving out of the cache for 30m
    set beresp.grace = 30m;
    set beresp.ttl = 48h;
 
    # Remove some unwanted headers
    unset beresp.http.Server;
    unset beresp.http.X-Powered-By;
 
    # Respect the Cache-Control=private header from the backend
    if (beresp.http.Cache-Control ~ "private") {
        set beresp.http.X-Cacheable = "NO:Cache-Control=private";
    } elsif (beresp.ttl < 1s) { 	
        set beresp.ttl   = 5s;
 	set beresp.grace = 5s;
 	set beresp.http.X-Cacheable = "YES:FORCED";
    } else {
 	set beresp.http.X-Cacheable = "YES";
    }
 
    # Don't cache responses to posted requests or requests with basic auth
    if ( req.request == "POST" || req.http.Authorization ) {
         return (hit_for_pass);
    }
 
    # Cache error pages for a short while
    if( beresp.status == 404 || beresp.status == 500 || beresp.status == 301 || beresp.status == 302 ){
         set beresp.ttl = 1m;
         return(deliver);
    }
 
    # Do not cache non-success response
    if( beresp.status != 200 ){
    return(hit_for_pass);
    }
 
    return(deliver); }
 
sub vcl_deliver {
 
    # Add debugging headers to cache requests
    if (obj.hits > 0) {
        set resp.http.X-Cache = "HIT";
    }
    else {
        set resp.http.X-Cache = "MISS";
    }
 
}
 
sub vcl_error {
 
    # Try connecting to apache 3 times before giving up
    if (obj.status == 503 && req.restarts < 2) {
        set obj.http.X-Restarts = req.restarts;
        return(restart);
    }
    if (obj.status == 301) {
        set obj.http.Location = req.url;
        set obj.status = 301;
        return(deliver);
    }
 
}
 
sub vcl_hit {
 
    if (req.request == "PURGE"){
	set obj.ttl = 0s;
	error 200 "Varnish cache has been purged for this object.";
    }
 
}
 
sub vcl_miss {
 
    if (req.request == "PURGE") {
	error 404 "Object not in cache.";
    }
 
}

~$ vi /etc/apache2/ports.conf
...
NameVirtualHost *:8080
Listen 8080
...
 
~$ vi /etc/apache2/sites-enabled/dimitrieu
 
...
 
~$ vi /etc/default/varnish
...
DAEMON_OPTS="-a :80 \
             -T localhost:6082 \
             -f /etc/varnish/default.vcl \
             -S /etc/varnish/secret \
             -s malloc,256m"
...
 
~$ /etc/init.d/apache2 restart
~$ /etc/init.d/varnish restart

# Make sure OpenVZ does not use up all memory
ulimit -s 2048