dnsdist - threads vs multiple listeners

[victoredvardsson]

Hello,

I have been looking through the dnsdist documentation and hope someone can provide clarity on this topic.
Historically, if you wanted to handle more traffic, my understanding is that you would add multiple addLocal() statements for the same IP.

Now with the YAML configuration, you can set the number of threads for a listener, but there is also an option to add multiple listeners for the same IP.

My question is: does adding X number of threads to a listener give me the same result as adding multiple listeners to the same IP? Are there any drawbacks to either approach?

Reference: https://www.dnsdist.org/reference/yaml-settings.html#bindconfiguration

[rgacogne]

My question is: does adding X number of threads to a listener give me the same result as adding multiple listeners to the same IP?

Yes. There is a slight difference for DoT and DoH frontends because with threads the underlying TLS context is shared between all frontends, while there is one separate TLS context per frontend if you declare multiple frontends. This should be completely transparent for most users.

Are there any drawbacks to either approach?

I find the threads approach cleaner but other than that and the slight different noted above, nope :)