Multi varnish setup and purging

[Eliezer Croitoru]

This is a bit old but I still have interest in this topic.

I am running a HA varnish with 3 hosts and I am not using the ban method 
but a regular PURGE with one url per request.
The way I do that for multiple hosts is via a custom reverse proxy(I 
will publish it later)that I have written in GOlang which has a list of 
back-end servers and which "broadcast"(ie sending each host a single 
request) to all the back-ends.
It will do that in the background so the application will just receive a 
200 response fast and the logs will show any signs of errors.

Since I have never used the ban option I cannot tell you if it meets 
your goals.
If you have solved this issue somehow then I will be happy to hear about 
the solution you have implemented.

Thanks,
Eliezer

On 13/08/2015 08:18, Andy Fase wrote:
> Hi there
> We're in the process of taking our 3.0.X single varnish instance into a
> HA multi
> varnish setup.
> My plan for caching was to initially use a hash director to pass
> requests from
> whatever the incoming varnish instance is to a specific one (based on
> the URL)
> so that the cache for a given URL will only be kept in one place.
> Hence the flow would be
> Varnish -> varnish -> backend
> However our overall application makes heavy use of wildcard purging via
> the ban
> command. As each URL in a wildcard ban could be on different varnish
> instances I
> don't see how this could actually work?
> Does anyone have any experience in supporting purging multiple varnish
> servers
> while supporting wildcard purges without having to get the application
> to send
> separate purge requests to all varnish instances?
> I was thinking of maybe a round robin director with all varnish instances
> defined as backends and some vcl to actually do the ban but return a
> error (to
> the calling varnish instance) so that the ban gets sent to all varnish
> instances
> (because each of them return an error after the ban)
> Any thoughts appreciated
> Cheers Andy
>
>
> _______________________________________________
> varnish-misc mailing list
> varnish-misc at varnish-cache.org
> https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
>