Install Varnish

Added on May 18th, 2012 and marked as caching install varnish webserver

Install varnish:

apt-get install varnish

An example Varnish config file /etc/varnish/default.vcl, taken from Daniel Miessler:

backend default {
    .host = "localhost";
    .port = "8080";
}

acl purge {
    "localhost";
}

sub vcl_recv {
    if (req.request == "PURGE") {
        if (!client.ip ~ purge) {
            error 405 "Not allowed.";
        }
        return(lookup);
    }

    if (req.url ~ "^/$") {
        unset req.http.cookie;
    }
}

sub vcl_hit {
    if (req.request == "PURGE") {
        set obj.ttl = 0s;
        error 200 "Purged.";
    }
}

sub vcl_miss {
    if (req.request == "PURGE") {
        error 404 "Not in cache.";
    }

    if (!(req.url ~ "wp-(login|admin)")) {
        unset req.http.cookie;
    }

    if (req.url ~ "^/[^?]+.(jpeg|jpg|png|gif|ico|js|css|txt|gz|zip|lzma|bz2|tgz|tbz|html|htm)(?.|)$") {
        unset req.http.cookie;
        set req.url = regsub(req.url, "?.$", "");
    }

    if (req.url ~ "^/$") {
        unset req.http.cookie;
    }
}

sub vcl_fetch {
    if (req.url ~ "^/$") {
        unset beresp.http.set-cookie;
    }

    if (!(req.url ~ "wp-(login|admin)")) {
        unset beresp.http.set-cookie;
    }
}

Starting Varnish

By default Varnish listens on port 6081 and uses localhost:6082 as its administration. We want to use Varnish as a replacement for the default webserver, so we must change 6081 into 80. Open /etc/default/varnish, find DAEMON_OPTS and make sure it is defined as:

DAEMON_OPTS="-a :80
             -T localhost:6082
             -f /etc/varnish/default.vcl
             -S /etc/varnish/secret
             -s malloc,256m"

Since Varnish is going to run on port 80, you need to change the nginx configuration to run on a different port:

listen 8080;

Start Varnish with the following command (also restart nginx):

service varnish start
service nginx restart

Varnish for WordPress

Purge Varnish

Useful commands

Background information