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Bump...</div>
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I am personally interested in this as well. I'm trying to something similar albeit on a smaller scale.</div>
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-Mike</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> dnsdist <dnsdist-bounces@mailman.powerdns.com> on behalf of Rais Ahmed via dnsdist <dnsdist@mailman.powerdns.com><br>
<b>Sent:</b> Wednesday, March 23, 2022 5:01 PM<br>
<b>To:</b> dnsdist@mailman.powerdns.com <dnsdist@mailman.powerdns.com><br>
<b>Subject:</b> [dnsdist] dnsdist[29321]: Marking downstream IP:53 as 'down'</font>
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<div class="PlainText">Hi,<br>
Thanks for reply...!<br>
<br>
We have configured setMaxUDPOutstanding(65535) and still we are seeing backend down, logs are showing frequently as below.<br>
<br>
Timeout while waiting for the health check response from backend 192.168.1.1:53<br>
Timeout while waiting for the health check response from backend 192.168.1.2:53<br>
<br>
Please have a look at below dnsdist configuration and help us to find misconfiguration (16 Listeners & 8+8 backends added as per vCPUs available (2 Socket x 8 Cores):<br>
<br>
controlSocket('127.0.0.1:5199')<br>
setKey("")<br>
<br>
---- Listen addresses<br>
addLocal('192.168.0.1:53', { reusePort=true })<br>
addLocal('192.168.0.1:53', { reusePort=true })<br>
addLocal('192.168.0.1:53', { reusePort=true })<br>
addLocal('192.168.0.1:53', { reusePort=true })<br>
addLocal('192.168.0.1:53', { reusePort=true })<br>
addLocal('192.168.0.1:53', { reusePort=true })<br>
addLocal('192.168.0.1:53', { reusePort=true })<br>
addLocal('192.168.0.1:53', { reusePort=true })<br>
addLocal('192.168.0.1:53', { reusePort=true })<br>
addLocal('192.168.0.1:53', { reusePort=true })<br>
addLocal('192.168.0.1:53', { reusePort=true })<br>
addLocal('192.168.0.1:53', { reusePort=true })<br>
addLocal('192.168.0.1:53', { reusePort=true })<br>
addLocal('192.168.0.1:53', { reusePort=true })<br>
addLocal('192.168.0.1:53', { reusePort=true })<br>
addLocal('192.168.0.1:53', { reusePort=true })<br>
<br>
---- Back-end server<br>
newServer({address='192.168.1.1', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=1})<br>
newServer({address='192.168.1.1', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=2})<br>
newServer({address='192.168.1.1', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=3})<br>
newServer({address='192.168.1.1', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=4})<br>
newServer({address='192.168.1.1', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=5})<br>
newServer({address='192.168.1.1', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=6})<br>
newServer({address='192.168.1.1', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=7})<br>
newServer({address='192.168.1.1', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=8})<br>
newServer({address='192.168.1.2', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=9})<br>
newServer({address='192.168.1.2', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=10})<br>
newServer({address='192.168.1.2', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=11})<br>
newServer({address='192.168.1.2', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=12})<br>
newServer({address='192.168.1.2', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=13})<br>
newServer({address='192.168.1.2', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=14})<br>
newServer({address='192.168.1.2', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=15})<br>
newServer({address='192.168.1.2', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=16})<br>
<br>
setMaxUDPOutstanding(65535)<br>
<br>
---- Server Load Balancing Policy<br>
setServerPolicy(leastOutstanding)<br>
<br>
---- Web-server<br>
webserver('192.168.0.1:8083')<br>
setWebserverConfig({acl='192.168.0.0/24', password='Secret'})<br>
<br>
---- Customers Policy<br>
customerACLs={'192.168.1.0/24'}<br>
setACL(customerACLs)<br>
<br>
pc = newPacketCache(300000, {maxTTL=86400, minTTL=0,<br>
temporaryFailureTTL=60, staleTTL=60, dontAge=false})<br>
getPool(""):setCache(pc)<br>
<br>
setVerboseHealthChecks(true)<br>
<br>
Servers Specs are as below:<br>
Dnsdist LB Server Specs: 16 vCPUs, 16 GB RAM, Virtio NIC (10G) with 16 Multiqueues.<br>
Backend bind9 servers Specs: 16 vCPUs, 16GM RAM, Virtio NIC (10G) with 16 Multiqueues.
<br>
<br>
We are trying to handle 500K qps (will increase hardware specs, If required) or with above specs atleast 100K qps.<br>
<br>
<br>
Regards,<br>
Rais <br>
<br>
-----Original Message-----<br>
From: dnsdist <dnsdist-bounces@mailman.powerdns.com> On Behalf Of dnsdist-request@mailman.powerdns.com<br>
Sent: Wednesday, March 23, 2022 5:00 PM<br>
To: dnsdist@mailman.powerdns.com<br>
Subject: dnsdist Digest, Vol 79, Issue 3<br>
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Today's Topics:<br>
<br>
1. dnsdist[29321]: Marking downstream IP:53 as 'down' (Rais Ahmed)<br>
2. Re: dnsdist[29321]: Marking downstream IP:53 as 'down'<br>
(Remi Gacogne)<br>
<br>
<br>
----------------------------------------------------------------------<br>
<br>
Message: 1<br>
Date: Tue, 22 Mar 2022 23:00:25 +0000<br>
From: Rais Ahmed <rais.ahmed@tes.com.pk><br>
To: "dnsdist@mailman.powerdns.com" <dnsdist@mailman.powerdns.com><br>
Subject: [dnsdist] dnsdist[29321]: Marking downstream IP:53 as 'down'<br>
Message-ID:<br>
<PAXPR08MB70737E4E1CCEFC4A7F61E1E6A0179@PAXPR08MB7073.eurprd08.prod.outlook.com><br>
<br>
Content-Type: text/plain; charset="us-ascii"<br>
<br>
Hi,<br>
<br>
We have configured dnsdist instance to handle around 500k QPS, but we are seeing downstream down frequently once QPS reached above 25k. below are the logs which we found to relative issue.<br>
<br>
dnsdist[29321]: Marking downstream server1 IP:53 as 'down'<br>
dnsdist[29321]: Marking downstream server2 IP:53 as 'down'<br>
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------------------------------<br>
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Message: 2<br>
Date: Wed, 23 Mar 2022 10:32:22 +0100<br>
From: Remi Gacogne <remi.gacogne@powerdns.com><br>
To: Rais Ahmed <rais.ahmed@tes.com.pk>, "dnsdist@mailman.powerdns.com"<br>
<dnsdist@mailman.powerdns.com><br>
Subject: Re: [dnsdist] dnsdist[29321]: Marking downstream IP:53 as<br>
'down'<br>
Message-ID: <5a95cbeb-7c82-9bc1-0b4c-8726f814432e@powerdns.com><br>
Content-Type: text/plain; charset=UTF-8; format=flowed<br>
<br>
Hi,<br>
<br>
> We have configured dnsdist instance to handle around 500k QPS, but we > are seeing downstream down frequently once QPS reached above 25k. below > are the logs which we found to relative issue.<br>
><br>
> dnsdist[29321]: Marking downstream server1 IP:53 as 'down'<br>
><br>
> dnsdist[29321]: Marking downstream server2 IP:53 as 'down'<br>
<br>
You might be able to get more information about why the health-checks are failing by adding setVerboseHealthChecks(true) to your configuration.<br>
<br>
It usually happens because the backend is overwhelmed and needs to be tuned to handle the load, but it might also be caused by a network issue, like a link reaching its maximum capacity, or by dnsdist itself being overwhelmed and needing tuning (like increasing
the number of<br>
newServer() directives, see [1]).<br>
<br>
[1]: <br>
<a href="https://dnsdist.org/advanced/tuning.html#udp-and-incoming-dns-over-https">https://dnsdist.org/advanced/tuning.html#udp-and-incoming-dns-over-https</a><br>
<br>
Best regards,<br>
--<br>
Remi Gacogne<br>
PowerDNS.COM BV - <a href="https://www.powerdns.com/">https://www.powerdns.com/</a><br>
<br>
<br>
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