Hi Marco, On Wed, Nov 27, 2019 at 08:38:03AM +0100, Marco Corte wrote: > Hello! > > I see a strange behaviour of the DNS resolution on version 2.0.9 and 2.0.10, > but I do not know since when this happens. > > On Ubuntu 18.04, I set up haproxy to use the local DNS service provided by > systemd. > Actually I see that haproxy tries to resolve the names every second. > The resolution is successful, the TTL in the answer is 1800s or longer.
It's the interval of your server checks. The resolution is sent at the same frequency as the checks. The reason is that in environments using dynamic server addresses, you definitely need to check your address at the same frequency you care for the server's availability. In addition, in some fast-recycling environments (AWS used to be like this, I don't know if it's still the case), when you shut down your server, it was possible that its IP address was reassigned so fast that the server didn't even have the time to appear dead, and the traffic could continue to be delivered to someone else's server! If it bothers you (I don't really see why), you can increase the "inter" value on your servers to check them less often and as such refresh their address less often. Hoping this helps, Willy