Hi, You will have to define a probe, otherwise Varnish will consider the backend to be healthy by default. You would then be able to manually make it sick, but for automatic health, you need probing.
Kind regards, -- Guillaume Quintard On Sat, Jul 4, 2020 at 8:47 AM hamidreza hosseini <[email protected]> wrote: > Thanks for your answer, > I read yor blog post, you wrote there that fallback director will check > the health status of the servers and it will choose one of them that is > healthy(First one) , so by this explanation i dont need to define the prob > for my backends to understand that my backends are healthy or not, is it > true? > is this config file enough for my purpose? > " > import directors; > > backend alpha1 { .host = "192.168.0.101"; } > backend alpha2 { .host = "192.168.0.201"; } > backend err { .host = "192.168.0.150"; } > > sub vcl_int { > new alpha_rr = directors.round_robin(); > alpha_rr.add_backend(alpha1); > alpha_rr.add_backend(alpha2); > > new alpha_fb = directors.fallback(); > alpha_fb.add_backend(alpha_rr.backend()); > alpha_fb.add_backend(err); > } > " > Best Regards > ------------------------------ > *From:* Guillaume Quintard <[email protected]> > *Sent:* Saturday, July 4, 2020 8:11 AM > *To:* hamidreza hosseini <[email protected]> > *Cc:* [email protected] <[email protected]> > *Subject:* Re: solution for Active/Passive Backend > > Hi, > > You want to use probes and the fallback director. > > Relevant documentation: > to define a probe: > https://varnish-cache.org/docs/6.4/reference/vcl.html?highlight=probe#probes > to attach it to backends: > https://varnish-cache.org/docs/6.4/reference/vcl.html?highlight=probe#backend-definition > the fallback director: > https://varnish-cache.org/docs/6.4/reference/vmod_directors.html?highlight=fallback#directors-fallback > > i also wrote these blog posts a long time ago, but they are still valid: > https://info.varnish-software.com/blog/backends-load-balancing > https://info.varnish-software.com/blog/backends-load-balancing-part-2 > > The first one goes through probes, and the second one explores directors, > including the fallback one. > > Hope that helps > > -- > Guillaume Quintard > > > On Sat, Jul 4, 2020 at 7:14 AM hamidreza hosseini <[email protected]> > wrote: > > Hi, > I want to have 2 or 3 backends in the Varnish config file but just one of > them workes as an active backend and whenever my active backend failed , > the second backend become active and respond the requests. (In other hand, > I dont want to have two backend for responding clients and just one of them > works at the same time, and it check the health status of my active backend > , whenever it is was unhealthy , varnish switch to the second or third > backend.) > Best Regards. > _______________________________________________ > varnish-misc mailing list > [email protected] > https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc > >
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