I'm teaching Propellor how to configure primary DNS servers, including generating their zone files. It turns out that the complete configuration for this will look like so:

            & Dns.primary hosts "olduse.net"
                    ( Dns.mkSOA "ns1.kitenet.net" 100
                            [ NS (AbsDomain "ns1.kitenet.net")
                            , MX 0 (AbsDomain "kitenet.net")
                            ]
                    )

Where are the IP addresses, you may be wondering? Surely that config should say what the address of olduse.net is, and probably also include some subdomains.

No :) Propellor has a neater way. The addresses and subdomains are configured as properties of the hosts that constitute the domain.

    , host "branchable.com"
            & ipv4 "66.228.46.55"
            & cname "olduse.net" -- not really a CNAME, but I have not found a better word
    , host "diatom.kitenet.net"
            & ipv4 "107.170.31.195"
            & JoeySites.oldUseNetServer hosts
               `requires` cname "nntp.olduse.net"

I did not write this expecting to be able to leave out the SOA addresses like that. It just happened. A very happy accident.