[dnsdist] dnsdist 1.4 and Debian Buster

[Remi Gacogne]

Hi Chris,

On 8/8/19 9:14 AM, Chris wrote:
> I have put a copy of the configs here, the two 'conf-d' named files live
> in /etc/dnsdist/dnsdist.conf.d:

Thanks a lot, your help is very much appreciated!

> Sorry if its a bit hard to read, I created a puppet module which takes
> the data from a more human friendly yaml file.

That's actually one of the most readable configuration I have seen in a
while, don't worry ;-)

> Also if it helps, I don't think I mentioned it before but the query load
> I have on different instances varies, there are a couple of instances
> that get basically no queries as they are for IP's that are not
> allocated yet. Those instances don't have a problem at the same time,
> they continue to work as normal.

That's very weird, I don't see anything unusual in your configuration,
the backtrace seems to indicate that all threads are working as
expected, and I even see some UDP queries being received and forwarded
in the strace (albeit very few, you can spot them easily by looking for
"recvmsg resumed" with grep).

Would you mind providing a 'lsof -n -p <pid of dnsdist>' while it's
stuck? Would you by any chance be able to do a strace when it's stuck,
while at the same time sending a few UDP queries to it, ideally with an
easily recognizable qname like "why-is-dnsdist-not-responding.to.this." ?
Do you collect some metrics via prometheus? I don't see a carbon export,
you might want to send some metrics to our public metronome server [1]
for a while, just from one box, we might some spot something there.

Also, apart from Debian being upgraded from Stretch to Buster and
dnsdist from 1.3.x to 1.4.0-beta2, did anything else change in your setup?

[1]: https://metronome1.powerdns.com

Best regards
-- 
Remi Gacogne
PowerDNS.COM BV - https://www.powerdns.com/

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