[dnsdist] Question on backend selection

[Mailing Lists]

My preferred way to achieve this (which will ensure during periods of unexpectedly high QPS this will not result in queries being sent to backend03/backend04):

newServer({name="backend01",pool="primary",...})
newServer({name="backend02",pool="primary",...})
newServer({name="backend03",pool="secondary",...})
newServer({name="backend04",pool="secondary",...})

addAction(PoolAvailableRule("primary"), PoolAction("primary"))
addAction(PoolAction("secondary"))

________________________________
From: dnsdist <dnsdist-bounces at mailman.powerdns.com> on behalf of Daniel Stirnimann via dnsdist <dnsdist at mailman.powerdns.com>
Sent: Wednesday, 2 June 2021 16:28
To: Tom <lists at verreckte-cheib.ch>; dnsdist at mailman.powerdns.com <dnsdist at mailman.powerdns.com>
Subject: Re: [dnsdist] Question on backend selection

Hello Tom,

This might come very close to what you are looking for:

newServer({name="backend01",order=1, qps=5000,...})
newServer({name="backend02",order=1, qps=5000,...})
newServer({name="backend03",order=2, qps=5000,...})
newServer({name="backend04",order=2, qps=5000,...})

setServerPolicy(firstAvailable)

"The firstAvailable policy, picks the first available server that has
not exceeded its QPS limit, ordered by increasing ‘order’. If all
servers are above their QPS limit, a server is selected based on the
leastOutstanding policy. For now this is the only policy using the QPS
limit."
https://dnsdist.org/guides/serverselection.html

Daniel


On 02.06.21 09:19, Tom via dnsdist wrote:
> Hi list
>
> Using dnsdist 1.5.2 with four configured backend servers
> (backend01-backend04).
>
> Is there a way to configure dnsdist to use backend03 and backend04 only,
> if backend01 and backend02 are not answering on the healthcheck? Or
> better: use backend03 or backend04 only if backend01 or backend02 are down.
>
> Any hints?
>
> Thank you.
> Kind regards,
> Tom
> _______________________________________________
> dnsdist mailing list
> dnsdist at mailman.powerdns.com
> https://mailman.powerdns.com/mailman/listinfo/dnsdist
>
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