[dnsdist] Backend Questions
remi.gacogne at powerdns.com
Fri Oct 7 09:17:39 UTC 2022
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
You can force a server in the "up" state using the 'setUp()' method, see
> My current config is a few years old tested with dnsdist 1.3. These
> days, dnsdist was faster when I added the listen port multiple times,
> and also add the single backend server multiple times, to have more
> receiver threads. For example:
> Is it still (dnsdist 1.6/1.7) useful/necessary to add listenSockets and
> Backendserver multiple times to improve performance?
I'm afraid so, yes. We have been thinking about a better syntax/design
for spawning multiple threads without having to duplicate the lines, but
haven't settled on and implemented a new syntax yet. Ideally we would
like to avoid breaking compatibility with existing setups, both for the
configuration files and for the metrics, but we might have to make a
breaking change in a new major version.
PowerDNS.COM BV - https://www.powerdns.com/
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