Multiple instances of varnish

Hettwer, Marian mhettwer at
Fri May 6 09:54:16 CEST 2011

On 05.05.11 19:00, "david raistrick" <drais at> wrote:

>On Thu, 5 May 2011, Mike Franon wrote:
>> I am trying to see if there is a way with using a single instance
>> 1)  Varnish using VCL to recognize that it is a bot
>> 2)  If it is a bot request, varnish will then use a different backend.
>Sure.  You don't need multiple varnishes for this.
>Define your backend, create a rule that matches on the headers you're
>matching on, set the backend.
>I don't have anything that matches on user agents (which is what I assume
>you're looking at on the F5), and I'm not going to look at the docs to
>find out how to match on them, but an example that does the same thing

If the F5 is able to recognize a bot, let it just insert a custom http
header (X-F5-Found-Bot or something like that) and later match in vcl_recv
on this header.

Pretty much like this:

sub vcl_recv {
 if (req.http.X-F5-Found-Bot) {
  set req.backend = backendforbots;


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