Example VCL for Supercharging Content Delivery presentation

default.vcl

#
# This is an example VCL file for Varnish.
#
# It does not do anything by default, delegating control to the
# builtin VCL. The builtin VCL is called when there is no explicit
# return statement.
#
# See the VCL chapters in the Users Guide at https://www.varnish-cache.org/docs/
# and http://varnish-cache.org/trac/wiki/VCLExamples for more examples.

# Marker to tell the VCL compiler that this VCL has been adapted to the
# new 4.0 format.
vcl 4.0;

import directors;

# Health check
probe health_check {
    .url = "/";
    .timeout = 1s;
    .interval = 5s;
}

acl purge {
	"127.0.0.1";
	"45.55.163.206";
}

# Default backend definition. Set this to point to your content server.
backend server1 {
    .host = "45.55.140.8";
	.probe = health_check;
}
backend server2 {
    .host = "45.55.163.196";
	.probe = health_check;
}
backend server3 {
    .host = "45.55.163.193";
	.probe = health_check;
}

sub vcl_init {
    new vdir = directors.round_robin();
    vdir.add_backend(server1);
    vdir.add_backend(server2);
    vdir.add_backend(server3);
}

sub vcl_recv {
    # Happens before we check if we have this in cache already.
    #
    # Typically you clean up the request here, removing cookies you don't need,
    # rewriting the request, etc.
    if (req.method == "PURGE") {
        if (!client.ip ~ purge) {
            return(synth(403,"Forbidden"));
        }
        return(purge);
    }

	set req.backend_hint = vdir.backend();

    if (req.url ~ "wp-admin|wp-login") {
        return (pass);
    }

    unset req.http.cookie;
}

sub vcl_backend_response {
    # Happens after we have read the response headers from the backend.
    #
    # Here you clean the response headers, removing silly Set-Cookie headers
    # and other mistakes your backend does.
    if (bereq.url ~ ".png$|.gif$|.jpg$") {
        set beresp.ttl = 8h;
    }

    if (!beresp.http.Cache-Control) {
        set beresp.ttl = 5m;
    }

    if (beresp.status == 200 && beresp.http.content-length == "0") {
        return(retry);
    }

	set beresp.grace = 1h;
}

sub vcl_deliver {
    # Happens when we have all the pieces we need, and are about to send the
    # response to the client.
    #
    # You can do accounting or modifying the final object here.
    if (obj.hits > 0) {
        set resp.http.X-Cache = "HIT";
    } else {
        set resp.http.X-Cache = "MISS";
    }
}