Re: Caching OSM tiles - how to not overload backends?
Hello,
@tranxene50 if implementing a vmod can be very challenging, using haproxy
can be a great solution here. Please refer to this blog post:
https://www.haproxy.com/fr/blog/four-examples-of-haproxy-rate-limiting/ (or
in french ;)
https://www.haproxy.com/fr/blog/four-examples-of-haproxy-rate-limiting/ ).
The very first step is about setting a maximum connections number and a
queuing. Using haproxy as your backend would require low engineering and a
minimum overage.
Regards,
Le lun. 15 juin 2020 à 20:02, Dridi Boukelmoune a écrit :
> On Sun, Jun 14, 2020 at 2:32 AM tranxene50
> wrote:
> >
> > Hello!
> >
> > Please forgive my bad English, I live in France.
> >
> > Summary: how to cache - with Varnish - Open Street Map PNG images
> without overloading OSM tiles servers?
> >
> > The question seems related to Varnish backends and ".max_connections"
> parameter.
> >
> > A far as I know, if ".max_connections" is reached for a backend, Varnish
> sends 503 http errors.
> >
> > I understand the logic but would it be possible to queue these incoming
> requests and wait until the selected backend is really available?
> >
> > backend a_tile {
> > .host = "a.tile.openstreetmap.org";
> > .port = "80";
> > .max_connections = 2;
> > }
> >
> > If Varnish have, let's say 100 incoming requests in 1 second, how can I
> handle this "spike" without overloading the backend?
> >
> > All my google searches were "dead ends" so I think the question is
> poorly formulated.
> >
> > Note 1 : using [random|round_robin] directors could be a temporary
> solution
> > Note 2 : libvmod-dynamic is great but does not limit backend
> simultaneous connexions
> >
> > Many thanks for your help!
>
> Bonsoir,
>
> Unfortunately we don't have any sort of queuing on the backend side,
> so besides implementing your own backend transport from scratch in a
> VMOD there is currently no solution.
>
> Cordialement,
> Dridi
> ___
> varnish-misc mailing list
> varnish-misc@varnish-cache.org
> https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
>
___
varnish-misc mailing list
varnish-misc@varnish-cache.org
https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
Re: Caching OSM tiles - how to not overload backends?
On Sun, Jun 14, 2020 at 2:32 AM tranxene50
wrote:
>
> Hello!
>
> Please forgive my bad English, I live in France.
>
> Summary: how to cache - with Varnish - Open Street Map PNG images without
> overloading OSM tiles servers?
>
> The question seems related to Varnish backends and ".max_connections"
> parameter.
>
> A far as I know, if ".max_connections" is reached for a backend, Varnish
> sends 503 http errors.
>
> I understand the logic but would it be possible to queue these incoming
> requests and wait until the selected backend is really available?
>
> backend a_tile {
> .host = "a.tile.openstreetmap.org";
> .port = "80";
> .max_connections = 2;
> }
>
> If Varnish have, let's say 100 incoming requests in 1 second, how can I
> handle this "spike" without overloading the backend?
>
> All my google searches were "dead ends" so I think the question is poorly
> formulated.
>
> Note 1 : using [random|round_robin] directors could be a temporary solution
> Note 2 : libvmod-dynamic is great but does not limit backend simultaneous
> connexions
>
> Many thanks for your help!
Bonsoir,
Unfortunately we don't have any sort of queuing on the backend side,
so besides implementing your own backend transport from scratch in a
VMOD there is currently no solution.
Cordialement,
Dridi
___
varnish-misc mailing list
varnish-misc@varnish-cache.org
https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
Re: varnish node without gcc
Hi, Just to add a detail here, you can have a look at "varnishadm param.show cc_command" to see how varnish transforms the C into a shared object. -- Guillaume Quintard On Mon, Jun 15, 2020 at 6:26 AM Dridi Boukelmoune wrote: > On Mon, Jun 15, 2020 at 12:29 PM wrote: > > > > Hi, > > > > is it possible to compile the final merged vcl configuration in a pre > > step and then pushing it to the frontend nodes? So, no vcl config and > > gcc on the frontend. Just a bin blob and a restart of the service. > > It is technically possible to pass a blob around, but Varnish insists > on compiling VCL locally. > > > Can this "compile while restart" activity splitted into to seprated > > ones? Is that possible? > > There is no restart involved, VCL is meant to be loadable on the fly. > > Dridi > ___ > varnish-misc mailing list > varnish-misc@varnish-cache.org > https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc > ___ varnish-misc mailing list varnish-misc@varnish-cache.org https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
Re: varnish node without gcc
On Mon, Jun 15, 2020 at 12:29 PM wrote: > > Hi, > > is it possible to compile the final merged vcl configuration in a pre > step and then pushing it to the frontend nodes? So, no vcl config and > gcc on the frontend. Just a bin blob and a restart of the service. It is technically possible to pass a blob around, but Varnish insists on compiling VCL locally. > Can this "compile while restart" activity splitted into to seprated > ones? Is that possible? There is no restart involved, VCL is meant to be loadable on the fly. Dridi ___ varnish-misc mailing list varnish-misc@varnish-cache.org https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
varnish node without gcc
Hi, is it possible to compile the final merged vcl configuration in a pre step and then pushing it to the frontend nodes? So, no vcl config and gcc on the frontend. Just a bin blob and a restart of the service. Can this "compile while restart" activity splitted into to seprated ones? Is that possible? -- Thanks, Leon ___ varnish-misc mailing list varnish-misc@varnish-cache.org https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
