Usage of 'local' plugin in coredns

Question

As I am new to coredns configurations in kubernetes and I'm trying to explore plugins provided by coredns in kubernetes. I see a plugin named local which will respond with a reply to local requests. But I could not understand a use-case where this plugin will be exactly useful for. Can someone explain with an example how it can be make use of?

Thanks in advance!!!

Answer 1

As the author of the local plugin for CoreDNS explains, localhost.<searchpath> queries are hitting coredns, which is wrong. So, he wrote this plugin to intercept localhost.<'domain'> queries and return the correct response.

From the official CoreDNS github web page:

local will respond with a basic reply to a "local request". Local request are defined to be names in the following zones: localhost, 0.in-addr.arpa, 127.in-addr.arpa and 255.in-addr.arpa and any query asking for localhost.<domain>.

With local enabled any query falling under these zones will get a reply. This prevents the query from "escaping" to the internet and putting strain on external infrastructure.

You can check the code of the local plugin here. I don't see similar to the unbound local-zone nodefault functionality there.

See all in-tree plugins for CoreDNS here.