Varnish round-robin loadbalancing with Virtualhost (Namebased)
Norberto Meijome
numard at gmail.com
Sat Aug 31 15:49:48 CEST 2013
Bind to different ports?
On 31/08/2013 12:00 AM, "Tharanga Abeyseela" <tharanga.abeyseela at gmail.com>
wrote:
> That is my requirement !!!. i'm using the same IP address for both hosts,
> and need to do the load-balancing between two servers. thats what i wanted
> to know, Actually i'm playing with different varnish configs :) on my
> virtual box., thought to give this config a try....but that didnt work. it
> is working perfectly with different IP's, or IP based Vhosts.
> Thanks Thierry for the response.
> cheers,
> Tharanga
>
>
> On Fri, Aug 30, 2013 at 10:46 PM, MAGNIEN, Thierry <
> thierry.magnien at sfr.com> wrote:
>
>> Hi,
>>
>> I think I understood the point :
>> - you have 2 backends hosted under the same IP address : www.backend1.comand
>> www.backend2.com
>> - your varnish server gets requests (for example) for www.frontend.com
>> - you want requests to be load-balanced between your 2 backends BUT this
>> would need the bereq.host to be rewritten to either www.backend1.com or
>> www.backend2.com
>> - BUT you can't do this in your VCL because you don't know which backend
>> will be selected.
>>
>> In fact, this would need the director to rewrite the host header once the
>> real backend has been selected, which I don't think is possible.
>>
>> Anyway, I still wonder why the hell you need varnish for this, where a
>> HAProxy would certainly do the trick ;-)
>>
>> Regards,
>> Thierry
>>
>>
>> De : varnish-misc-bounces+thierry.magnien=sfr.com at varnish-cache.org[mailto:
>> varnish-misc-bounces+thierry.magnien=sfr.com at varnish-cache.org] De la
>> part de Per Buer
>> Envoyé : vendredi 30 août 2013 13:36
>> À : Tharanga Abeyseela
>> Cc : Varnish misc
>> Objet : Re: Varnish round-robin loadbalancing with Virtualhost (Namebased)
>>
>> Hi Tharanga,
>>
>> You seem not to understand. Varnish will just pass the host header in the
>> request to the backend you specify. Looking at the VCL you provided you put
>> both the backends into one director. This is probably not what you want to
>> do.
>>
>> Try removing the director. Name the directors xxx and yyy and have the
>> VCL look like.
>>
>> sub vcl_recv {
>> if (req.http.host ~ "xxx.com") {
>> req.backend = xxx;
>> } else if (..
>>
>> }
>> Also the next bit doesn't make sense:
>> if (req.request)
>> {
>> return(pass);
>> }
>>
>> }
>>
>> On Fri, Aug 30, 2013 at 10:42 AM, Tharanga Abeyseela <
>> tharanga.abeyseela at gmail.com> wrote:
>> Hi,
>>
>> Actually i tried that link, still it is not working. it should work for a
>> ip based virtual host, but namebased virtual host is not working.
>> becuase main request coming to varnish/80 and varnish should redirect the
>> traffic to the backend server based on my round-robin director. when you
>> resolve dns for those two hosts (xxx.com and yyy.com) it reuturns the
>> same IP. that is 192.168.0.100. But there should be a way to send the
>> host-header to apache. Not sure how it works here. But when i use different
>> server (192,168.0.200/ zzz.com) it works without any issue, it
>> roundrobin the traffic. This is an issue with namebased virtualhost.
>> varnish recevie the traffic (cluster.com is my varnish server), then it
>> use it vcl to redirect based on my round-robin setting. but how it can send
>> the traffic to the correct virtualhost. because it gets only the same IP
>> address from the DNS. I managed to change the default behaviour by
>> forcefully setting the host-header as follows to my other
>> virtualhost(yyy..com)
>> set.req.host="yyy.com" ;
>> then all request went to yyy.com instead of xxx.com. but what i want is
>> a round-robin fashio...to send traffic. first req to xxx.com/ 2nd req to
>> yyy.com and so on..
>>
>> I was trying to find some resourses on the net, stackoverflow etc..but no
>> luck yet.
>>
>> Thanks again for your help
>> Cheers,
>> Tharanga
>>
>> On Fri, Aug 30, 2013 at 5:05 PM, Per Buer <perbu at varnish-software.com>
>> wrote:
>> Hi Tharanga,
>>
>> You seem to be a bit confused about how the directors and backends work
>> in Varnish. Please read this:
>>
>>
>> https://www.varnish-cache.org/docs/trunk/users-guide/vcl-backends.html#backends-and-virtual-hosts-in-varnish
>>
>> Note that the .host property of the backend has NOTHING to do with the
>> virtual host.
>>
>> On Fri, Aug 30, 2013 at 2:02 AM, Tharanga Abeyseela <
>> tharanga.abeyseela at gmail.com> wrote:
>> Hi Per,
>> Thanks for the reply. Actually my set up looks like this.
>>
>> cluster.com - 192.168.0.200 (varnish/port 80)
>> xxx.com - 192.168.0.100 (apache,namebased vhost/8080 - backendname -
>> website)
>> yyy.com - 192.168.0.100 (apache,namebased vhost/8080 -backendname - api)
>> cluster.com is the varnish server and front-end connections coming to
>> this and rewrite to other defined back-ends (round-robin based balancing)
>>
>>
>>
>> backend website {
>> .host = "xxx.com";
>> .port = "8080";
>>
>> }
>> backend api {
>> .host = "yyy.com";
>> .port = "8080";
>>
>> }
>>
>> director clust round-robin {
>> { .backend = api; }
>> { .backend = website; }
>>
>> }
>>
>> sub vcl_recv {
>> set req.backend = clust;
>> if (req.request)
>> {
>> return(pass);
>> }
>>
>> }
>>
>> when i hit the cluster.com , it is always going to xxx.com, but what i
>> need to do is first request go to xxx.com second request yyy.com and so
>> on...when i add another server (different host/different IP say
>> 192.168.0.111/zzz.com, and a different backend) , it goes like this
>> first request - xxx.com
>> second request - xxxx.com
>> third request - zzz.com
>>
>> but i can change the default behavior by setting up set req.host =
>> yyy.com and then it will goes to
>> first request - yyy.com
>> second request - yyy.com
>> third request - zzz.com
>> this is something to do with the host-header forwarding to the correct
>> back-end. how should i add that functionality to the vcl_recv ?
>> appreciate your help on this, this is working perfectly with other
>> servers (different servers, not with namebased vhosts)
>> cheers,
>> Tharanga
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> On Thu, Aug 29, 2013 at 11:58 PM, Per Buer <perbu at varnish-software.com>
>> wrote:
>> Hi mate,
>>
>> On Thu, Aug 29, 2013 at 3:17 PM, Tharanga Abeyseela <
>> tharanga.abeyseela at gmail.com> wrote:
>> (..)
>>
>> But how should i send host-headers to varnish to redirect to the correct
>> server, This is always going to xxx.com.
>>
>> You don't. :-)
>>
>> You need to dispatch the request to the right backend in vcl_recv and
>> have the backend handle that host. You could start rewriting the host in
>> vcl_recv, but I would advise against it.
>>
>> So, if you have two vhosts handled by "website" you just set that as the
>> backend in vcl_recv.
>>
>> --
>>
>> Per Buer
>> CTO | Varnish Software AS
>> Phone: +47 958 39 117 | Skype: per.buer
>> We Make Websites Fly!
>>
>> Winner of the Red Herring Top 100 Europe Award 2013
>>
>>
>>
>>
>>
>>
>>
>> --
>>
>> Per Buer
>> CTO | Varnish Software AS
>> Phone: +47 958 39 117 | Skype: per.buer
>> We Make Websites Fly!
>>
>> Winner of the Red Herring Top 100 Europe Award 2013
>>
>>
>>
>>
>>
>>
>>
>> --
>>
>> Per Buer
>> CTO | Varnish Software AS
>> Phone: +47 958 39 117 | Skype: per.buer
>> We Make Websites Fly!
>>
>> Winner of the Red Herring Top 100 Europe Award 2013
>>
>>
>>
>>
>
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