Detecting health of Backend in Director in VCL

[Chris Davies]

On Jul 14, 2011, at 9:05 AM, Shibashish wrote:
> On Thu, Jul 14, 2011 at 6:30 PM, Chris Davies <isp at daviesinc.com> wrote:
> I've got a director set up with three nodes, and I can see how to check the health of the director, but, is there any method to check the health of a particular backend in the director?
> 
> Each backend host is checked with its own probe...
> 
> .probe = { 
>                 .url = "/probe.cgi";
>                 .timeout = 34 ms; 
>                 .interval = 1s; 
>                 .window = 10;
>                 .threshold = 8;
>         }
> 
> More at https://www.varnish-cache.org/trac/wiki/BackendPolling

And in VCL, how do I tell the health of the backend within a director?