Hello Bartosz, On Fri, 13 Nov 2020 at 10:08, Bartosz <bartosz-hapr...@unreachablehost.net> wrote: > > Are we really the only ones with this issue? Has no one else seen this > change in behaviour? Or otherwise have any idea where it's coming from? > > Or at least confirm whether they do or don't see the same behaviour.
I don't think you can setup sockets this way, I think this is an incorrect configuration leading to undefined behavior. The fact the behavior then changes across different kernels is not a surprise. I'd suggest you run haproxy with noreuseport [1] temporarily, and check if your kernel refuses to bind() to those IP's - it likely will. This indicates an unsupported configuration (by your kernel, not by haproxy). Lukas [1] https://cbonte.github.io/haproxy-dconv/2.0/configuration.html#noreuseport
