[resolver] more than 1024 concurrent queries from 127.0.0.1:60796

Help!
1

When using the haproxy as docker swarm loadbalancer, following this example: https://www.haproxy.com/blog/haproxy-on-docker-swarm-load-balancing-and-dns-service-discovery/

It works, but on the nodes where haproxy is running the logs are complaining about DNS the number of concurrent DNS queries:

Mar 03 14:53:37 server1 env[880]: time="2022-03-03T14:53:37.333838162+01:00" level=error msg="[resolver] more than 1024 concurrent queries from 127.0.0.1:43874"
Mar 03 14:53:41 server1 env[880]: time="2022-03-03T14:53:41.340168712+01:00" level=error msg="[resolver] more than 1024 concurrent queries from 127.0.0.1:34287"
Mar 03 14:53:49 server1 env[880]: time="2022-03-03T14:53:49.359534246+01:00" level=error msg="[resolver] more than 1024 concurrent queries from 127.0.0.1:46246"
Mar 03 14:53:53 server1 env[880]: time="2022-03-03T14:53:53.363898081+01:00" level=error msg="[resolver] more than 1024 concurrent queries from 127.0.0.1:44218"
Mar 03 14:53:57 server1 env[880]: time="2022-03-03T14:53:57.379037667+01:00" level=error msg="[resolver] more than 1024 concurrent queries from 127.0.0.1:48512"
Mar 03 14:54:01 server1 env[880]: time="2022-03-03T14:54:01.385777693+01:00" level=error msg="[resolver] more than 1024 concurrent queries from 127.0.0.1:46361"
Mar 03 14:54:13 server1 env[880]: time="2022-03-03T14:54:13.397559970+01:00" level=error msg="[resolver] more than 1024 concurrent queries from 127.0.0.1:50449"
Mar 03 14:54:17 server1 env[880]: time="2022-03-03T14:54:17.445595460+01:00" level=error msg="[resolver] more than 1024 concurrent queries from 127.0.0.1:38100"
Mar 03 14:54:21 server1 env[880]: time="2022-03-03T14:54:21.378573392+01:00" level=error msg="[resolver] more than 1024 concurrent queries from 127.0.0.1:60210"
Mar 03 14:54:25 server1 env[880]: time="2022-03-03T14:54:25.382760283+01:00" level=error msg="[resolver] more than 1024 concurrent queries from 127.0.0.1:35228"
Mar 03 14:54:29 server1 env[880]: time="2022-03-03T14:54:29.386742360+01:00" level=error msg="[resolver] more than 1024 concurrent queries from 127.0.0.1:58273"

That does seem a lot of DNS queries in a minute which are not related to “real” proxy traffic.

Does anybody recognizes this? and is there a solution?
Going back to a static haproxy config solves the problem as well, but still where do these massive number of DNS requests come from?

2

There is actually not a lot of information in this post that we could use to troubleshoot your issue.

I suggest you start by sharing output of haproxy -vv, your configuration, haproxy logs, and a traffic capture of the local dns traffic on 127.0.0.1.