Can NS-type queries be supported ?

[barmettlerl]

From the README.md

Currently only supports A-type queries, all other queries result in NODATA responses.

We have k8gb setup with multiple clusters. And we'd like to configure it in a way that we can do zone delegation to coredns instance per region. like dev.example.com can do zone delegation to region1.dev.example.com. And the Coredns responsible for the zone region1.dev.example.com should be the one in region1.

For this to work, coredns needs to support NS-type queries.

I've checked the Coredns, externaldns, k8gb - setup, but externaldns does only support coredns with etcd backend (which we'd like to avoid)

[barmettlerl]

Actually I managed to provide NS support by using the coredns file plugin. I added the file plugin before the usage of the k8gb_crd plugin and provided it with the necessary NS entries:

Corefile for coredns-crd-plugin for west.example.ch:

    west.example.ch:5353 {
        errors
        health
        ready
        prometheus 0.0.0.0:9153
        file /etc/coredns/zones/db.west.example.ch {
          # Optional: You might want to enable secondary transfers if this is a secondary NS
          # transfer from 1.2.3.4 # IP of primary NS
        }
        forward . /etc/resolv.conf
        k8s_crd {
            filter k8gb.absa.oss/dnstype=local
            negttl 300
            loadbalance weight
        }
    }

    example.ch:5353 {
      errors
      health
      ready
      prometheus 0.0.0.0:9153
      file /etc/coredns/zones/db.example.ch {
        # Optional: You might want to enable secondary transfers if this is a secondary NS
        # transfer from 1.2.3.4 # IP of primary NS
      }
      forward . /etc/resolv.conf
      k8s_crd {
          filter k8gb.absa.oss/dnstype=local
          negttl 30
          loadbalance weight
      }
    }

/etc/coredns/zones/db.west.example.ch:

    $TTL 3600
    @ IN SOA  west.example.ch.  (
                                    2025061901 ; Serial: {{- now | date "20060102" }}01 - INCREMENT THIS ON CHANGES!
                                    7200       ; Refresh (2 hours)
                                    3600       ; Retry (1 hour)
                                    1209600    ; Expire (2 weeks)
                                    3600       ; Minimum (1 hour)
                                    )
            IN NS   ns1.west.example.ch.

    ns1     IN A     <WEST COREDNS IP>

/etc/coredns/zones/db.example.ch:

    $TTL 3600
    @ IN SOA example.ch. (
                                    2025061901 ; Serial: {{- now | date "20060102" }}01 - INCREMENT THIS ON CHANGES!
                                    7200
                                    3600
                                    1209600
                                    3600
                                    )
            IN NS   ns1.example.ch.
            IN NS   ns2.example.ch.

    ns1     IN A    <WEST COREDNS IP>
    ns2     IN A    <NORTH COREDNS IP>

    west IN NS ns1.west.example.ch.
    west IN A <WEST COREDNS IP>

    north IN NS ns1.north.example.ch.
    north IN A <NORTH COREDNS IP>

Note: the coredns ip is the Ip of the service type loadbalancer

[ytsarev]

@barmettlerl that's a nice one! Would you be willing to contribute the related piece to k8gb.io documentation?