Hi, Thanks for reply...! We have configured setMaxUDPOutstanding(65535) and still we are seeing backend down, logs are showing frequently as below.
Timeout while waiting for the health check response from backend 192.168.1.1:53 Timeout while waiting for the health check response from backend 192.168.1.2:53 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): controlSocket('127.0.0.1:5199') setKey("") ---- Listen addresses addLocal('192.168.0.1:53', { reusePort=true }) addLocal('192.168.0.1:53', { reusePort=true }) addLocal('192.168.0.1:53', { reusePort=true }) addLocal('192.168.0.1:53', { reusePort=true }) addLocal('192.168.0.1:53', { reusePort=true }) addLocal('192.168.0.1:53', { reusePort=true }) addLocal('192.168.0.1:53', { reusePort=true }) addLocal('192.168.0.1:53', { reusePort=true }) addLocal('192.168.0.1:53', { reusePort=true }) addLocal('192.168.0.1:53', { reusePort=true }) addLocal('192.168.0.1:53', { reusePort=true }) addLocal('192.168.0.1:53', { reusePort=true }) addLocal('192.168.0.1:53', { reusePort=true }) addLocal('192.168.0.1:53', { reusePort=true }) addLocal('192.168.0.1:53', { reusePort=true }) addLocal('192.168.0.1:53', { reusePort=true }) ---- Back-end server newServer({address='192.168.1.1', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=1}) newServer({address='192.168.1.1', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=2}) newServer({address='192.168.1.1', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=3}) newServer({address='192.168.1.1', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=4}) newServer({address='192.168.1.1', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=5}) newServer({address='192.168.1.1', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=6}) newServer({address='192.168.1.1', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=7}) newServer({address='192.168.1.1', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=8}) newServer({address='192.168.1.2', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=9}) newServer({address='192.168.1.2', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=10}) newServer({address='192.168.1.2', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=11}) newServer({address='192.168.1.2', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=12}) newServer({address='192.168.1.2', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=13}) newServer({address='192.168.1.2', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=14}) newServer({address='192.168.1.2', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=15}) newServer({address='192.168.1.2', maxCheckFailures=3, checkInterval=5, weight=4, qps=40000, order=16}) setMaxUDPOutstanding(65535) ---- Server Load Balancing Policy setServerPolicy(leastOutstanding) ---- Web-server webserver('192.168.0.1:8083') setWebserverConfig({acl='192.168.0.0/24', password='Secret'}) ---- Customers Policy customerACLs={'192.168.1.0/24'} setACL(customerACLs) pc = newPacketCache(300000, {maxTTL=86400, minTTL=0, temporaryFailureTTL=60, staleTTL=60, dontAge=false}) getPool(""):setCache(pc) setVerboseHealthChecks(true) Servers Specs are as below: Dnsdist LB Server Specs: 16 vCPUs, 16 GB RAM, Virtio NIC (10G) with 16 Multiqueues. Backend bind9 servers Specs: 16 vCPUs, 16GM RAM, Virtio NIC (10G) with 16 Multiqueues. We are trying to handle 500K qps (will increase hardware specs, If required) or with above specs atleast 100K qps. Regards, Rais -----Original Message----- From: dnsdist <dnsdist-boun...@mailman.powerdns.com> On Behalf Of dnsdist-requ...@mailman.powerdns.com Sent: Wednesday, March 23, 2022 5:00 PM To: dnsdist@mailman.powerdns.com Subject: dnsdist Digest, Vol 79, Issue 3 Send dnsdist mailing list submissions to dnsdist@mailman.powerdns.com To subscribe or unsubscribe via the World Wide Web, visit https://mailman.powerdns.com/mailman/listinfo/dnsdist or, via email, send a message with subject or body 'help' to dnsdist-requ...@mailman.powerdns.com You can reach the person managing the list at dnsdist-ow...@mailman.powerdns.com When replying, please edit your Subject line so it is more specific than "Re: Contents of dnsdist digest..." Today's Topics: 1. dnsdist[29321]: Marking downstream IP:53 as 'down' (Rais Ahmed) 2. Re: dnsdist[29321]: Marking downstream IP:53 as 'down' (Remi Gacogne) ---------------------------------------------------------------------- Message: 1 Date: Tue, 22 Mar 2022 23:00:25 +0000 From: Rais Ahmed <rais.ah...@tes.com.pk> To: "dnsdist@mailman.powerdns.com" <dnsdist@mailman.powerdns.com> Subject: [dnsdist] dnsdist[29321]: Marking downstream IP:53 as 'down' Message-ID: <paxpr08mb70737e4e1ccefc4a7f61e1e6a0...@paxpr08mb7073.eurprd08.prod.outlook.com> Content-Type: text/plain; charset="us-ascii" Hi, 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. dnsdist[29321]: Marking downstream server1 IP:53 as 'down' dnsdist[29321]: Marking downstream server2 IP:53 as 'down' -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mailman.powerdns.com/pipermail/dnsdist/attachments/20220322/2befd6e2/attachment-0001.htm> ------------------------------ Message: 2 Date: Wed, 23 Mar 2022 10:32:22 +0100 From: Remi Gacogne <remi.gaco...@powerdns.com> To: Rais Ahmed <rais.ah...@tes.com.pk>, "dnsdist@mailman.powerdns.com" <dnsdist@mailman.powerdns.com> Subject: Re: [dnsdist] dnsdist[29321]: Marking downstream IP:53 as 'down' Message-ID: <5a95cbeb-7c82-9bc1-0b4c-8726f8144...@powerdns.com> Content-Type: text/plain; charset=UTF-8; format=flowed Hi, > 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. > > dnsdist[29321]: Marking downstream server1 IP:53 as 'down' > > dnsdist[29321]: Marking downstream server2 IP:53 as 'down' You might be able to get more information about why the health-checks are failing by adding setVerboseHealthChecks(true) to your configuration. 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 newServer() directives, see [1]). [1]: https://dnsdist.org/advanced/tuning.html#udp-and-incoming-dns-over-https Best regards, -- Remi Gacogne PowerDNS.COM BV - https://www.powerdns.com/ ------------------------------ Subject: Digest Footer _______________________________________________ dnsdist mailing list dnsdist@mailman.powerdns.com https://mailman.powerdns.com/mailman/listinfo/dnsdist ------------------------------ End of dnsdist Digest, Vol 79, Issue 3 ************************************** _______________________________________________ dnsdist mailing list dnsdist@mailman.powerdns.com https://mailman.powerdns.com/mailman/listinfo/dnsdist