Using varnish as a cache for more than one website

[Davies Matt J A (LCSS)]

Thanks Marcus

I got there in the end with the documentation, wonderful stuff :-)

backend a {
  .host = "machinename";
  .port = "80";
}

backend b {
  .host = "machinename";
  .port = "8082";
}

#
#Below is a commented-out copy of the default VCL logic.  If you
#redefine any of these subroutines, the built-in logic will be
#appended to your code.
#
sub vcl_recv {
    if (req.http.host == "a.com") {
      set req.backend = a;
    }
    
    if (req.http.host == "b.com") {
      set req.backend = b;
    }

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

sub vcl_fetch {
    if (req.url ~ "^/") {
        unset obj.http.set-cookie;
        set obj.ttl = 600s;
    }
}


BTW, is it good form to reply to the list or the person who replied?  Told you I was green :-)

Matt


On 29 Jun 2010, at 11:23, Marcus Smith wrote:

> Davies Matt J A (LCSS) wrote:
>> Hello everyone
>> 
>> What is the best practice way of setting up varnish to act as a cache
>> for more than one web site?
>> 
>> I can see I can make multiple backend, and I've read that I can run
>> multiple instances of varnish, I'm just wondering what is the best
>> practice way?
>> 
>> One thing I can't quite get my head around is how do I tell varnish
>> which incoming URL to serve with which backend, or instance.
>> 
>> Scenario
>> 
>> I've got our DNS boys to point a.com and b.com at our varnish server,
>> which is going to act as a cache for both sites, both sites being
>> very different and needing different rules.  Rules that may collide
>> also.
>> 
>> If I use the multiple instance route, how do associate an instance
>> with an incoming URL?
> 
> With a single instance of varnish, having defined your back ends, you
> might for example do something like this:
> 
> 
> sub vcl_recv {
> 	if (req.http.host == "a.com") {
> 		set req.backend = backend-A;
> 		# More site-specific rules here
> 		}
> 
> 	elsif (req.http.host ~ "(www\.)?b\.com") {
> 		set req.backend = backend-B;
> 		# More site-specific rules here
> 		}
> 
> 	# More sites here
> 
> 	else {
> 		error 404 "Unknown host!";
> 	}
> }
> 
> 
> best wishes,
> Marcus
> 
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