[dnsdist] Backend Questions

Klaus Darilion klaus.darilion at nic.at
Wed Nov 2 12:38:10 UTC 2022

(resent to the list)

Hi Remi!

> On 07/10/2022 10:53, Klaus Darilion via dnsdist wrote:
> > We use dnsdist with 1 single backend server (PDNS). So if this backend
> > is overloaded, dnsdist will detect the backend as DOWN. Hence, the only
> > server for this backend pool down. How will dnsdist behave if all
> > servers for a backend pool are down? Will it stop senden queries to the
> > backend, or will it still send queries to the DOWN server as there is no
> > UP server available?
> All of the built-in load balancing policies will stop forwarding queries
> when all the servers in the selected pool are down. It would be possible
> to write a custom load-balancing in Lua that does not do that, of
> course, but I don't think that's what you want in that case.
> > So it may be useful to disable healthchecks completely. How can this be
> > done?
> You can force a server in the "up" state using the 'setUp()' method, see
> [1].

Shouldn't newServer(...healthCheckMode='UP') also work? In my case it does not work. 
I have set healthCheckMode='UP' but:
showServers show status as "up" whereas after setUp() the status is "UP". And it still does helathchecks and status goes "down" if the backend is down.

What is wrong? The docs? Am I misinterpreting the docs? Bug?


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